Chapter 6: Anchored Masonry Veneer Systems

Chapter 6: Anchored Masonry Veneer Systems2020-02-22T03:52:33-07:00
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Fig. 6-1 Isabella Bird Community School in Denver, CO
(Mason Contractor: Dels Masonry, GC: Golden Triangle Construction Inc., Architect: Humphries Poli Architects)

The anchored masonry veneer wall systems in this guide consist of an anchored masonry veneer with concrete masonry unit (CMU), concrete, light-gauge steel stud framing, or wood framing backup wall structures. While many wall system variations and products may apply to these backup wall types and/or veneer options, this chapter focuses on preferred anchored masonry veneer systems and alternative products that have demonstrated success within Colorado and southern Wyoming. The typical components of these systems are described in Table 6-1. 

All systems described in this chapter are appropriate for low- and mid-rise residential or commercial buildings. Additionally, the CMU, concrete, and light-gauge steel framing backup wall systems are appropriate for high-rise residential or commercial buildings. 

Typical wall system details that illustrate the design concepts for CMU, steel stud-framed, and wood-framed backup wall structures are included at the end of this chapter. A concrete backup wall structure is not included within these details; however, it would be similar to those shown for a CMU backup wall.

Building Enclosure Control Layers

As noted in Chapter 3, an above-grade wall system provides control of liquid water, air, heat, and water vapor to serve as an effective and durable environmental separator. Control of these elements, specific to the general design of masonry wall systems, is provided by the following surface and control layer systems and/ or materials:

  • The water-shedding surface, comprising the cladding, flashing, and enclosure penetration components 
  • The water control layer, comprising the water-resistive barrier (WRB) system 
  • The air control layer, comprising the air barrier system 
  • The thermal control layer, comprising thermal insulation and other low-conductivity materials 
  • The vapor control layer, comprising vapor-retarding materials

For a summary of the relationship between building enclosure loads, control layers, and associated systems and materials, refer to Chapter 3. 

Table 6-1 illustrates the water-shedding surface and control layer locations for anchored masonry veneer with various backup wall structures. The control layers shown are specific to the types of air barrier system, WRB system, thermal insulation, and vapor control materials selected for representation and discussion within this chapter. The water-shedding surface and control layers are also shown on typical system details provided adjacent to each detail at the end of this chapter.

Water-Shedding Surface

The water-shedding surface reduces the water load on the enclosure. 

As shown in Table 6-1 the anchored masonry veneer cladding, including both mortar joints and masonry veneer units, is the primary water-shedding surface of the wall system. Additional wall system components include flashings and drip edges, sealant joints, and fenestration systems. 

To promote water shedding at the masonry veneer face, mortar joints are installed with a tooled concave (preferred) or “V” shape. The water-shedding surface is most effective when free of gaps except where providing drainage and/or ventilation. Movement joints and joints around fenestrations and penetrations are recommended to be continuously sealed with backer rod and sealant or counterflashed with a sheet-metal flashing to deflect wind-driven rain and shed water away from the air cavity. 

Water Control Layer

The water control layer is a continuous control layer designed and installed to act as the innermost boundary for water intrusion. In the anchored veneer wall system, the water-resistive barrier (WRB) system provides the function of water control along with flashings and wall penetrations (e.g., windows and doors). 

At the field-of-wall area of the anchored masonry veneer, the WRB system includes a WRB field membrane and accessories such as fluid-applied and flexible flashing membranes, sheetmetal flashings, sealants, tapes, and fasteners. To be effective, these materials must be continuous and shingle-lapped to promote a continuous drainage plane and water-shedding ability. Where flashing components exist within the system, such as at floor line and base-of-wall conditions, the back leg of the sheet-metal flashing is shingle-lapped into the WRB field membrane to drain water at the face of the WRB system and to the exterior of the masonry veneer. 

Where the WRB system is also part of the air barrier system, it will be sealed for airtightness using tapes, sealants, gaskets, and other components.

A WRB system generally has the following properties: 

  • Water-resistive – Resistant to the passage of liquid water when applied to a vertical, drained surface 
  • Durable – Durable and resistant to moisture, microbial growth, and wind pressures in addition to ultraviolet (UV) exposure either during installation or as anticipated during the building service life 
  • Compatible – Known chemical and adhesion compatibility with all accessory products such as self-adhered flashing membranes, fluid-applied membranes, sealants, and tapes 
  • Vapor permeable (i.e., transmits water vapor) – Such that the WRB system does not contribute to the development of condensation within the system that could damage enclosure layers or other elements 
  • Airtight – The air barrier is sealed for airtightness using tapes, sealants, gaskets and other components where the WRB system also performs as the air barrier system (i.e., the air barrier and WRB system)

WRB system components may also be required to comply with combustibility requirements set forth by the authority having jurisdiction. 

For the anchored masonry veneer wall systems discussed in this chapter, the WRB system is either:

  1.  The exterior facer of rigid board insulation and self-adhered or fluid-applied flashing materials, as depicted on the CMU wall and concrete backup wall in Table 6-1. This WRB system type is also applicable to a steel stud-framed backup wall. 
  2. A self-adhered sheet- or fluid-applied membrane installed over the wall sheathing and self-adhered or fluid-applied flashing materials, as depicted on a steel stud-framed backup wall in Table 6-1. This WRB system is also applicable to a CMU, concrete, or wood-frame back up wall. 
  3. A mechanically attached membrane and self-adhered or fluid-applied flashing materials, as depicted on a wood-framed backup wall in Table 6-1. This WRB system is typically not used on concrete or CMU backup walls due to the difficulty of temporarily attaching the membrane to the substrate. This WRB system may be used for low-rise steel stud-framed backup wall systems. This system is often avoided for a steel stud-framed backup wall system on higher rise applications due to the likelihood for construction-phase damage from high wind exposures.

The WRB system may also be a 2-part spray-applied closed-cell polyurethane foam insulation product with self-adhered flashing membranes. This approach is most common on concrete, CMU, or steel stud-framed backup walls. 

Table 6-2 summarizes common air barrier and WRB systems used with anchored masonry veneer systems. 

Masonry veneer anchors penetrate the WRB system and should be sealed as required by the WRB system manufacturer’s installation requirements. Typically, plate anchors are bed in a compatible sealant or fluid-applied flashing product or are attached through a self-adhered membrane patch, whereas screw anchors with gasketing washers are typically not required to be sealed. Where a ladder eye-wire masonry veneer attachment method is used, this guide recommends a fluid-applied WRB system; seal each wire penetration through the membrane with sealant, with a fluid-applied flashing material, or with a liberal application of fluid-applied field membrane as recommended by the membrane manufacturer. 

In many instances, the WRB system will also function as the air barrier system. In this case, the WRB system is required to have the performance properties of an air barrier system and to be continuously taped and/or sealed to control air flow.

Vapor Permeance

The vapor permeance of the WRB system (or air barrier and WRB system) is important to consider when selecting a system for water control. The vapor permeance of the WRB system must be considered relative to the vapor permeance of the other field-of-wall components (e.g., exterior wall sheathing, insulation type, insulation locations in wall, etc.). 

Vapor permeance classes and their corresponding vapor transmission rates are described in Chapter 3 on page 21. General guidance for Colorado- and southern Wyoming-based systems described in this guide are as follows:

CMU/Concrete

CMU and concrete wall backup systems are almost always insulated to the exterior of the wall; thus, the vapor permeance class of the WRB system may be of any class. 

Steel Stud-Framed and Wood-Framed

For steel stud-framed and wood-framed backup wall systems the WRB system may have a: 

  • Class IV vapor permeance properties regardless of the placement of insulation relative to the WRB system. Where used without exterior insulation or with a vapor permeable exterior insulation material (e.g., semi-rigid mineral fiber), this class provides the greatest opportunity for the wall system to dry to the exterior. This drying can be beneficial during the service life of the building and also helps relieve construction-related moisture that may be present. 
  • Class III vapor permeance properties when carefully evaluated against other system material properties and the thermal control layer.
  • Class I or II vapor permeance properties when at least half the wall system’s total nominal insulation R-value is exterior of the WRB system. For this case, the WRB system will also function as the vapor control layer and a separate vapor retarder membrane at the interior of the wall system may be omitted; however, should be confirmed with local jurisdictional requirements. The recommendation to provide half the wall system’s total nominal insulation R-value exterior of the WRB system is generally applicable to most projects occurring within Colorado and southern Wyoming. This value may need to be increased to 2 ⁄3 of the wall system’s total nominal R-value for some projects, particularly those located at higher elevations with colder temperatures (Climate Zone 7) or those expected to have greater than usual interior relative humidity conditions.
Table 6-2
*Sheathing membrane products (i.e., loose-laid sheets, self-adhered membrane, and fluid-applied membrane) are available in a range of permeance classes. In Colorado and southern Wyoming, typically these air and water control layers function as the vapor control layer when the membrane is a Class 1 or Class 2 vapor permeance. In this instance, these membranes should typically only be used when ½ of the wall’s total R-value of insulation is located outboard of this membrane.
**Refer to page 21 for the properties of each control layer. Systems listed can only perform as the control layer indicated when these properties are met.

Air Control Layer

The air control layer comprises of the air barrier system and is responsible for controlling the flow of air through the building enclosure, either inward or outward. Air flow is significant because it impacts heat flow (space conditioning), water vapor transport, and condensation on cold surfaces. Refer to Chapter 3 for a discussion regarding the air control layer and properties of the air barrier system. 

For the anchored masonry veneer systems shown in this guide, the air barrier system is the same as the WRB system (i.e., the air barrier and WRB system). The air barrier system must be continuous and fully taped and/or sealed to resist air flow; whereas the WRB system is not required to be continuously sealed to be effective, merely shingle-lapped. 

For anchored masonry wall systems, there are many types of air barrier systems available on the market today. Different types of air barrier system options are included in Table 6-2.

Vapor Control Layer

The vapor control layer retards or greatly reduces the flow of water vapor across the enclosure. Unlike the other control layers presented in this guide, the vapor control layer is not always necessary, nor is it always required to be continuous; the location and/or the physical properties of other materials within the assembly, including the wall sheathing, insulation, and air barrier and WRB system can also affect the need for or necessary properties of the vapor control layer.

CMU/Concrete

For CMU and concrete backup wall systems the insulated sheathing option shown in this chapter’s details provides a foil-faced backer (Class 1 permeance) on the interior face of the insulated sheathing and serves as the vapor control layer. 

Where a self-adhered sheet or fluid-applied WRB system is applied directly to the exterior face of the CMU or concrete (similar to the steel stud-framed wall system details shown in this chapter), a vapor control layer is not necessary; the risk of condensation development or damage to the structure due to outward vapor drive and condensation is unlikely because the system’s thermal insulation is located exterior of the wall structure and the air barrier and WRB system.

Steel Stud-Framed/Wood-Framed

For steel stud-framed and wood-framed backup walls, refer to Section 1405.3 of the governing International Building Code.1 Typical vapor retarder products include PVA vapor-retarding primer, asphalt-coated kraft paper, polyethylene sheet, or a polyamide film membrane.

Shelf Angle Flashing Options

In the shelf angle flashing options on this page the brick coursing changes when it meets the shelf angle. A sheet-metal flashing with hemmed drip edge and a compressible backer rod and sealant joint remain visible for the final installation. Weeps and/ or vents are located within the head joint of the first courses above and below the shelf angle. The projected hem of the drip edge diverts water from the wall cavity and from the veneer above to minimize runoff onto the wall areas below, minimizing staining and increasing the long-term durability of the cladding. The sheet-metal flashing or drip plate used within these options can compensate for construction tolerances within the wall framing, floor slab, and shelf angle. These options may be used with either a continuous shelf angle or standoff shelf angle design.

Fig. 6-2 Flexible membrane
Fig. 6-2 Flexible membrane

Option 1: Flexible Flashing Membrane

A flexible nonadhered flashing membrane is used to drain the wall cavity to the face of the veneer. The membrane is terminated with a termination bar at the top and shingle-lapped into the WRB field membrane. The nonadhered flashing membrane is held back approximately 1 inch from the face of the masonry to ensure it is not visible. The flashing membrane is sealed at the top of the termination bar to the prestrip membrane behind the shelf angle, at laps, and at its termination on the veneer. The nonadhered flashing membrane shown in this option is a cost-effective flashing option.

Fig. 6-3 Self-adhered membrane
Fig. 6-3 Self-adhered membrane

Option 2: Self-Adhered Flashing Membrane

A flexible self-adhered flashing membrane is used to drain the wall cavity to the face of the veneer. The membrane is adhered to the prestrip membrane behind the shelf angle and is shingle-lapped into the WRB field membrane. The self-adhered flashing membrane is terminated under the sheet-metal drip plate and approximately 1 inch from the face of the shelf angle. Typically, a high-temperature self-adhered membrane product is used to minimize the risk of “bleed-out” should the membrane be installed on top of the drip plate (see Fig. 6-7). The self-adhered flashing membrane in this option is adhered to the substrate and does not typically require further sealing at laps or terminations.

Fig. 6-4 Two-piece sheet-metal flashing
Fig. 6-4 Two-piece sheet-metal flashing

Option 3: Two-Piece Sheet-Metal Flashing

A two-piece sheet-metal flashing (typically formed from stainless steel) is used to drain the wall cavity to the face of the veneer. The sheet-metal flashing is shingle-lapped into the WRB field membrane. The sheet-metal flashing laps are sealed or soldered. This option eliminates the need for a separate flexible flashing membrane and provides a robust flashing material. The use of the two-piece profile allows the sheet-metal flashing below the course to float in or out as needed to compensate for construction tolerances without requiring significant modifications to the profile throughout the length of the wall.

In the shelf angle flashing options in this section, the brick coursing does not change when it meets the shelf angle; a lipped brick overhangs the face of the shelf angle. In the options depicted, either a sanded sealant joint or sheet-metal drip edge remain visible for the final installation. Weeps and/or vents are located within the head joint of the first courses above the flashing membrane and below the shelf angle. The use of a lipped brick is more sensitive to construction tolerances within the wall framing, floor slab, and shelf angle. If the shelf angle projects too far forward, it may be difficult to install the lipped brick without disruption to the plane of the veneer. These options may be used with either a continuous shelf angle or standoff shelf angle design.

Fig. 6-2 Flexible membrane
Fig. 6-2 Flexible membrane

Option 4: Flexible Flashing Membrane – Lipped Brick

A flexible nonadhered flashing membrane is used to drain the wall cavity to the face of the veneer. The membrane is terminated with a termination bar at the top and shingle-lapped into the WRB field membrane. The nonadhered flashing membrane laps onto the top of the first course of masonry and is held back approximately 1 inch from the face of the veneer to ensure it is not visible. The flashing membrane is sealed at the top of the termination bar to the prestrip membrane behind the shelf angle, at laps, and at its termination on the veneer. The cavity behind the first course of masonry on the shelf angle is grouted solid. This option does not provide a means to deflect water away from the veneer face and may encourage staining or efflorescence to develop.

Fig. 6-6 Self-adhered membrane with lipped brick
Fig. 6-6 Self-adhered membrane with lipped brick

Option 5: Self-Adhered Flashing Membrane – Lipped Brick

A flexible self-adhered flashing membrane is used to drain the wall cavity to the face of the veneer. The membrane is adhered to the prestrip membrane behind the shelf angle and is shingle-lapped into the WRB field membrane. The self-adhered flashing membrane is terminated under the sheet-metal drip plate. Typically, a high-temperature self-adhered membrane product is used to minimize the risk of “bleed-out” should the membrane be installed on top of the drip plate (see Fig. 6-7). The self-adhered flashing membrane in this option is adhered to the substrate and does not require further sealing at laps or terminations. The projected hem of the drip edge diverts water from the wall cavity and from the veneer above to minimize runoff onto the wall areas below, minimizing staining and increasing the long-term durability of the cladding; however, it can be difficult to form at inside and outside wall corner transitions.

Fig. 6-7 Example of self-adhered membrane “bleed-out” from a self-adhered flashing membrane at a shelf angle detail
Fig. 6-7 Example of self-adhered membrane “bleed-out” from a self-adhered flashing membrane at a shelf angle detail

Legend

  1. Self-adhered sheet- or fluid-applied air barrier and WRB field membrane
  2. Self-adhered sheet- or fluid-applied air barrier and WRB prestrip flashing or membrane
  3. Mortar collection mesh
  4. Hot-dipped galvanized steel shelf angle support
  5. Vent/weep at maximum 24 inches on-center
  6. Sheet-metal flashing with hemmed drip edge
  7. Sealant over backer rod
  8. Flexible non-adhered masonry flashing fastened to substrate with termination bar
  9. Transitional sheet-metal flashing over sheet-metal drip flashing
  10. Non-shrink grout
  11. Lipped brick, see Fig. 6-8
  12. Termination bar and sealant
* Size joint for project specific movement.
Fig. 6-8 Typical lipped brick dimensions
Fig. 6-8 Typical lipped brick dimensions

Anchored Masonry Veneer Penetrations

As with most exterior cladding materials, penetrations through masonry systems are common. Service penetrations, temporary scaffold tie-back supports, or structural penetrations, such as knife plate connections as shown in Fig. 6-9, are a common method of supporting balcony structures, building signage, and canopies. These penetrations are typically anchored to the building structure and penetrate the air and water control layers as shown in Fig. 6-10; they may also penetrate the thermal control layer. In anchored masonry veneer applications, the veneer and wall structure move independent of one another. This movement must be accounted for in the design while maintaining continuity of the water-shedding surface and the air and water control layers.

Fig. 6-9 Typical knife plate
Fig. 6-9 Typical knife plate penetrations through an anchored masonry veneer. Exterior sealants joint around the knife plate penetration and across the floor line transition, along with final cleaning, have not yet been performed.
Fig. 6-10 Typical structural knife plate
Fig. 6-10 Typical structural knife plate penetrations flashed with a foil-faced self-adhered flashing membrane similar to the sequence in Fig. 6-11. Also visible is a preformed penetration boot for a pipe penetration.

Water, Air, and Thermal Control Layer Considerations

Penetrations through the air and water control layers need to be detailed to prevent water intrusion and air leakage and to allow for an unobstructed drainage pathway around the penetration. Two common practices for detailing around penetrations are shown in the flashing sequences in Fig. 6-11 and Fig. 6-12: a self-adhered flashing membrane and a fluid-applied flashing membrane, both applied around and onto the penetration. Pre-formed, gasketed boots may also be used and are typically detailed similarly to Fig. 6-12.

Although Fig. 6-11 and Fig. 6-12 show a knife plate penetration, the flashing sequences may be used for most discreet penetrations through the masonry veneer. Large penetrations through the veneer (e.g., continuous steel channel supports, unit exhaust vents, etc.) may require alterations to the sequence, such as a sheet-metal head flashing, to ensure adequate cladding support and unobstructed drainage at the face of the WRB system.

While detailing around penetrations is important, continuity of the air and water control layer at the penetration is equally important. This may require sealing holes and wire penetrations within electrical boxes or installing sealant between sleeves and pipes. 

Penetrations extending through thermal insulation layers should also be evaluated on a case-by-case basis for thermal bridging effects and condensation potential. These risks can be minimized by using lower-conductivity penetration materials (e.g., PVC in lieu of steel for sleeves or pipes).

Differential Movement

When designing and detailing penetrations that project through an anchored masonry veneer, differential movement between the backup wall structure and veneer needs to be accommodated. Anticipate expansion of a clay masonry veneer and shrinkage of concrete and wood-framed structures. Additionally, weight applied to some connections (e.g., a balcony placed on a knife plate connection after the masonry veneer is in place) can introduce movement; thus, sealant joints between the masonry and penetration are designed for both compression and tension.

Sequencing

This guide recommends that penetrations through the water, air, and thermal control layers or masonry veneer are secured before the mason contractor begins work. Preplanning penetration locations and detailing can avoid schedule delays and cladding removals due to out-of sequence installations.
Fig. 6-11 Sheet-applied membrane flashing sequence
Fig. 6-11 Sheet-applied membrane flashing sequence

Sheet-Applied Air Barrier and WRB System – Flashing Sequence

  1. Framed wall sheathing (shown) or backup wall structure face (e.g., CMU) 
  2. Hot-dipped galvanized knife plate (shown) or other penetration secured to structure 
  3. Air barrier and WRB target sheet, notched around penetration 
  4. Air barrier and WRB field membrane, lapped below target sheet 
  5. Air barrier and WRB tape (typically not required with self-adhered air barrier and WRB systems) 
  6. Self-adhered flashing membrane, fit tightly onto penetration
  1. Continuous sealant at flashing membrane leading edges around penetration 
  2. Air barrier and WRB field membrane
  3. Continuous air barrier and WRB tape (typically not required with selfadhered air and WRB systems) 
  4. Masonry veneer 
  5. Continuous sealant over backer rod around penetration, size joint for project specific movement
Fig. 6-12 Fluid-applied membrane flashing sequence
Fig. 6-12 Fluid-applied membrane flashing sequence

Fluid-Applied Air Barrier and WRB System – Flashing Sequence

  1. Framed wall sheathing (shown) or backup wall structure face (e.g., CMU) 
  2. Hot-dipped galvanized knife plate (shown), or other penetration, secured to structure 
  3. Air barrier and WRB field membrane 
  4. Air barrier and WRB flashing membrane over field membrane and onto penetration 
  1. Exterior insulation, tight to penetration
  2. Masonry veneer
  3. Continuous sealant over backer rod around penetration, size joint for project specific movement

Thermal Control Layer

The thermal control layer controls heat flow and assists with controlling water vapor (e.g., condensation risk). The insulation in this chapter’s system is either exterior of the backup wall structure or within stud-framed cavities. At transition details, the thermal control layer also includes insulation at framed parapet cavities, roof assembly, underslab, and foundation elements. Windows and doors that penetrate the above-grade wall are also part of the thermal control layer. 

Where insulation is located exterior of the wall structure, this placement provides the following benefits: 

  1. Allows for the exterior insulation to extend across floor lines, which can be a large source of heat loss—especially for mass floor line conditions. 
  2. Keeps the structure warm and reduces the risk that condensation may develop inboard of the air barrier and WRB system. 
  3. Protects the air barrier and WRB system from both extreme temperature cycles and damage during veneer installation. 

For additional discussion on the thermal control layer, refer to Chapter 3. Chapter 8 can be referred to for additional discussion on wall system thermal performance and insulation types as well as energy code compliance strategies.

CMU/Concrete

For CMU and concrete backup wall systems the exterior insulation is the primary material that forms the thermal control layer. Interior insulation is acceptable but should be carefully selected and detailed to ensure that condensation risk (due to either vapor drive or air leakage condensation) is not increased. Refer to Chapter 7 for additional discussion on insulating interior of the CMU wall structure. In Colorado and southern Wyoming, the exterior insulation may be moisture-tolerant rigid board insulation (e.g., polyisocyanurate or XPS), closed-cell spray foam insulation, expanded polystyrene (EPS) or semi-rigid mineral fiber board insulation as shown in Fig. 6-13.

Fig. 6-13 Fluid-applied air barrier and WRB system. The field membrane is depicted over a concrete backup wall face. Exterior semi-rigid mineral fiber insulation, double-eye and pintle plate ties, and a CMU veneer are also shown.
Fig. 6-13 Fluid-applied air barrier and WRB system. The field membrane is depicted over a concrete backup wall face. Exterior semi-rigid mineral fiber insulation, double-eye and pintle plate ties, and a CMU veneer are also shown.

Steel Stud-Framed

For steel stud-framed backup wall systems, the framed cavity insulation and exterior insulation are the primary materials that form the thermal control layer for steel stud-framed walls. 

Cavity insulation is typically fiberglass or mineral fiber batt insulation product, or it may be spray foam insulation in some cases. Steel stud framing bridges cavity insulation and can significantly reduce the actual thermal performance (i.e., effective R-value) of the insulation. The high conductivity of steel can reduce cavity insulation R-values by 40 to 60%. Thus, exterior insulation is common in steel stud-framed backup wall systems. 

Where insulated sheathing is used as shown in Fig. 6-14, the exterior insulation may be moisture-tolerant rigid board insulation (e.g., polyisocyanurate or XPS). Closed-cell spray foam insulation rated for exterior wall cavity applications may also be appropriate.

Fig. 6-14 Insulated sheathing with water-resistive facer and fluidapplied flashing membrane over a steel stud-framed backup wall structure.
Fig. 6-14 Insulated sheathing with water-resistive facer and fluidapplied flashing membrane over a steel stud-framed backup wall structure.

Wood-Framed

The wall cavity insulation and the lower-conductivity wood framing that bridge this insulation form the thermal control layer in the wood-framed backup wall system. Exterior insulation may also be used with this system to improve thermal performance. 

Although masonry is defined as a noncombustible cladding material, the use of a combustible air barrier and WRB system or foam plastic insulation within a wall cavity can trigger fire propagation considerations and requirements. Depending on the local jurisdiction, IBC Section 1403.51 (regarding vertical and lateral flame propagation as it relates to a combustible WRB system) may require acceptance criteria for NFPA 285.2 Also address IBC Chapter 26 provisions when using foam plastic insulation within a wall cavity.

Exterior Sheathing

Exterior sheathing is often used outboard of the framed backup wall systems for anchored masonry veneer wall systems. 

CMU/Concrete

For CMU and concrete backup wall systems, the use of sheathing is not typical and air barrier and WRB systems or insulation products are applied directly to the CMU or concrete face.

Steel Stud-Framed

For steel stud-framed backup wall systems, a faced gypsum-based sheathing that is resistant to organic growth and moisture is most common. 

Some rigid board insulation systems that also serve as the air barrier and WRB system are attached directly over the face of steel stud-framed walls and may not require exterior sheathing.

Wood-Framed

For wood-framed backup wall systems, the exterior sheathing is typically a wood or faced gypsum product and is designated by structural requirements. Where wood products are used, plywood is generally recommended for its moisture tolerance. Where gypsum board is used, a glass mat reinforced facer in lieu of a paper-faced product is recommended for resistance to organic growth as well as its moisture resistance.

Fig. 6-15 Typical anchored masonry veneer with steel stud-framed backup wall structure. Exterior insulation and the air cavity are visible behind the veneer. A mortar collection net exists at the base of the wall.
Fig. 6-15 Typical anchored masonry veneer with steel stud-framed backup wall structure. Exterior insulation and the air cavity are visible behind the veneer. A mortar collection net exists at the base of the wall.

Water Deflection and Drainage

The anchored masonry veneer is expected to shed most water it is exposed to; however, some moisture is expected to penetrate the cladding and enter the air cavity behind the veneer. This moisture is drained through the air cavity and exits the cladding system where cross-cavity flashings and weeps are provided. A typical anchored masonry veneer wall cavity, at the base of the wall, is shown in Fig. 6-15.

Flashings

Flashings are used throughout anchored masonry veneer wall systems and are most commonly found above and below penetrations, at parapet copings, at base-of-wall transitions, and at floor line transitions. Typical flashings used within anchored masonry veneer wall systems are depicted throughout the details located at the end of this chapter. A general discussion regarding masonry flashings is provided in Chapter 4, while a discussion specific to floor line flashing detailing is provided on pages 63–64.

Drainage and Ventilation

Although the minimum air cavity depth per TMS 402-163 is 1 inch, this guide recommends a 2-inch air cavity depth between the anchored masonry veneer and exterior insulation (or sheathing) to provide sufficient drainage and ventilation behind the cladding. This larger air cavity depth minimizes the risk that mortar droppings will block the cavity and provides a construction tolerance for framing and veneer components. A 1-inch cavity may be considered where a strict quality control program is implemented to ensure mortar droppings are not allowed to collect within the cavity and where backup wall structure and veneer alignment does not encroach on the 1-inch dimension. Where the air cavity is reduced, which commonly occurs at fenestration rough openings with return brick (refer to Detail 6-10 at the end of this chapter), this guide recommends a compressible free-draining filler. Semi-rigid mineral fiber insulation may be appropriate where additional thermal insulation may benefit the enclosure detailing; mortar collection net material may be considered when thermal insulation exterior of the sheathing is not needed. Mortar should not be packed within these cavities. 

The air cavity is either vented with vents located at the bottom course of the wall section at veneer bearing locations or the cavity may also be ventilated by locating vents at the top and bottom coursing of each wall section. Both vented and ventilated anchored masonry veneer systems are used in Colorado and southern Wyoming. Ventilated systems provide more air flow behind the anchored masonry veneer and benefit assembly drying, which can increase long-term durability of the masonry veneer, of the wall sheathing, and of the components within the air cavity. 

As a best practice, weeps are located within the head joints at the bottom course of the anchored masonry veneer at veneer-bearing locations. In an anchored masonry veneer wall system, weeps drain moisture that may enter the air cavity behind the veneer. Where open cellular- or mesh-type weeps are used, weeps may also serve as vents (i.e., weep vents).

Fig. 6-16 Cellular weep vents at an anchored masonry veneer. Weep vents extend into the mortar bed joint to allow water within the air cavity to drain to the exterior.
Fig. 6-16 Cellular weep vents at an anchored masonry veneer. Weep vents extend into the mortar bed joint to allow water within the air cavity to drain to the exterior.

This guide recommends that weeps and vents are spaced at a maximum of 24 inches on-center (e.g., every two to three masonry units) and are filled with a cellular product that fills the head joint of a standard brick unit. Masons within Colorado and southern Wyoming generally do not prefer mesh filler products for weeps or vents. Additionally, this guide recommends avoiding weep tubes at vent locations because they provide far less ventilation and are easily blocked with mortar, insects, and other debris. Where top vents provide a ventilated veneer, this guide recommends that weeps are staggered from any vents located in courses below. During installation, it is important that weeps extend into the bed joint of the masonry veneer to facilitate drainage as shown in Fig. 6-16.

This guide recommends mortar collection nets at all veneer-bearing locations to prevent mortar from blocking the air cavity and weeps. Generally, a trapezoidal open-weave moisture-tolerant net is used.

Structural Considerations

In the anchored masonry veneer wall systems in this guide, the CMU, concrete, steel stud-framed, and wood-framed backup walls provide the primary structure of the wall system. It is the responsibility of the Designer of Record to ensure that all structural elements of the backup wall and veneer are designed to meet project-specific loads and local governing building codes. Details at the end of this chapter demonstrate generic placement of the reinforced elements and supports/anchors for diagrammatic purposes only.

Masonry Anchors

Masonry anchors (i.e., masonry ties) are used to connect the veneer to the backup wall structure. They are designed to resist the out-of-plane loads applied to the wall, typically wind and seismic. At the same time, anchors must be flexible to allow the veneer to move in-plane relative to the backup wall. Table 6-4 describes common anchor types and their applications.

Building codes provide prescriptive requirements for masonry anchors secured to concrete or masonry that include spacing, size, placement, and anchor type. These requirements are summarized in Table 6-3 and are based on TMS 402-163 provisions for adjustable anchors. Use of these prescriptive requirements is limited to anchored masonry veneer systems with a weight less than 40 psf, with a cavity depth no more than 6 5/8 inches, and where the ASCE-74 wind velocity pressure (qz) is less than 55 psf. Wall systems that exceed these criteria require the design professional to evaluate the building loads and materials and rationally design the anchorage system accordingly. Most masonry anchor manufacturers have empirical test data available to support the use of their anchorage systems when the cavity depth or load exceeds these criteria.

Table 6-3 also includes prescriptive spacing requirements for anchored masonry veneers for special requirements for Seismic Design Categories D, E, and F and high-wind zones with velocity pressures (qz) between 40 and 55 psf. These higher seismicity and wind speed areas are common to some parts of Colorado and southern Wyoming and are dependent on the geography and building occupancy category. Refer to local building code requirements to ensure seismicity and wind speed criteria are properly evaluated for the building occupancy and site conditions. To prevent pull-out or push-through of the anchor, TMS 402-163 requires ties be embedded a minimum of 1 1 ⁄2 inches into the veneer, with at least 5 ⁄8-inch mortar or grout cover at the outside face. The mortar bed thickness is to be at least twice the thickness of the anchor. To prevent excess movement between connecting parts of adjustable anchor systems, the clearance between components is limited to a maximum 1⁄16 of an inch. The vertical offset of adjustable pintle-type ties may not exceed 1 1⁄4 inches. For steel stud-framed wall systems, TMS 402-163 requires that masonry anchors are fastened directly to the steel stud framing through the exterior sheathing with minimum #10 corrosion-resistant screws (0.190-inch shank diameter). They should not be fastened to the sheathing alone.

For wood-framed wall systems, TMS 402-163 requires fastening masonry ties directly to the wood framing through the exterior sheathing. Masonry anchors are not to be fastened to the sheathing alone. The code requires 8d common nails or fasteners with equivalent or greater pull-out strength. For framed backup wall systems, while the code may allow a horizontal anchor spacing up to 32 inches on-center, spacing anchors horizontally is recommended for alignment with the typical stud spacing of 16 inches on-center.

Vertical Supports

Anchored masonry veneers are supported vertically by the building’s foundation or other structural components such as shelf angles and lintels as shown in Fig. 6-17. Vertical supports are designed to minimize cracking and deflection within the veneer; the support design considers the design loads, material type, moisture control, movement provisions, and constructibility.

This guide recommends that intermediate supports for masonry be provided with galvanized-steel shelf angles anchored to the structure as needed to limit deflection to less than L/600 as required by TMS 402-16.3 As noted in the Movement Joints sections in this chapter and in Chapter 4, this guide recommends a joint filled with a compressible material beneath the angle.

Where masonry is supported at openings within the veneer (e.g., windows and doors), shelf angles for larger openings or loose lintels at smaller openings are typically provided. Galvanized-steel loose lintels are recommended except where architectural design dictates reinforced masonry or precast concrete lintels for appearance. Where steel angle lintels span the opening, TMS 402-163 requires that the lintel bear a minimum of 4 inches onto the adjacent masonry at the jambs of the opening. 

Fig. 6-17 Stand off shelf angle floor line support

Refer to the details at the end of this chapter for building enclosure detailing of typical support elements. 

CMU/Concrete

TMS 402-163 does not place any height restrictions or requirements for intermediate support of masonry with concrete or masonry backings except in Seismic Design Categories D, E, and F where the veneer is to be supported at each floor line. However, the design should provide intermediate support to accommodate movement and prevent cracking of the veneer associated with differential movement of the veneer, ties, building structure, and other building components. Unless dictated by the code, this guide recommends that intermediate supports are provided every 20 feet or every 2 floors, whichever is greater, for structural considerations and to facilitate drainage and ventilation of the rainscreen cavity.

Steel Stud-Framed

For steel stud-framed backup wall systems, TMS 402-163 requires the anchored masonry veneer to be supported by noncombustible construction; any veneer that exceeds 30 feet in height must be supported at each story above 30 feet. Masonry below 30 feet in height must also be supported at each floor when used in Seismic Design Categories D, E, and F. Best practice for commercial construction is to support the lowest portion of the masonry cladding directly on the concrete foundation wall.

Wood-Framed

For wood-framed backings, TMS 402-163 allows anchored masonry veneer supported vertically by noncombustible construction to be installed up to a height of 30 feet (or 38 feet at a gable). Wherever the masonry veneer is supported by wood construction, it must be supported every 12 feet. Best practice for commercial wood-framed construction is to support the lowest portion of the masonry cladding directly on the concrete foundation wall. 

For all backup wall types it is also important to consider vertical supports from a building enclosure thermal performance aspect, particularly at floor lines. Supports can create thermal bridges through exterior insulation and can significantly reduce the effectiveness of this insulation layer. This thermal bridging can be minimized by using intermediate standoff supports as further discussed in Chapter 8.

Table 6-3 Summary of TMS 402-16 provisions for adjustable anchors
* Seismic design categories as determined by ASCE 7
† High wind includes wind velocity pressures between 40 psf and 55 psf as determined by ASCE 7 and when the building’s mean roof height is less than or equal to 60 ft
‡ For openings larger than 16-inches in either dimension

Corrosion Resistance

It is best practice to match the durability and longevity of metal components to that expected of the masonry veneer. Metal components include veneer anchors, vertical support ledgers and lintels, sheet-metal flashings, and fasteners. This guide includes discussion for common corrosion-resistant materials; however, it is the Designer of Record’s responsibility to appropriately select a level of corrosion resistance for project-specific application/ exposure and the expected longevity of the masonry system.

It is common to provide hot-dipped galvanized carbon steel masonry veneer anchors that comply with ASTM A1535 Class B-2 or AISI Type 304 or Type 316 stainless steel per ASTM A580.6 Steel support angles such as shelf angle supports and loose lintels are at minimum hot-dipped galvanized and comply with ASTM A123.7 Best practice is to use sheet-metal flashing components of ASTM A6668 Type 304 or 316 stainless steel, which is nonstaining and resistant to the alkaline content of mortar materials. Where stainless steel sheet-metal flashing components are not economically feasible or aesthetically desirable, prefinished sheet metal may be appropriate. Where used, this guide recommends the base sheet metal is a minimum G90 hot-dipped galvanized coating in conformance with ASTM A6539 or minimum AZ50 galvalume coating in conformance with ASTM A792.10 This guide also recommends coating the exposed top finish of the sheet metal with an architectural-grade coating conforming to AAMA 621.11

Fasteners used with metal components should be corrosion resistant, either hot-dipped galvanized steel or stainless steel to match adjacent metal components.

When used with preservative-treated wood, also consider fastener selection to prevent galvanic corrosion.

Accommodating Movement

In an anchored masonry veneer system, clay masonry will expand, concrete masonry veneer units will shrink, and mortar joints will shrink. Clay masonry veneer systems require expansion joints located throughout the veneer and concrete masonry veneer systems require control joints. These joints minimize stresses within the veneer and between dissimilar materials such as at window jamb–to-veneer interfaces. 

To avoid damage to the veneer or other wall components, it is crucial to consider differential movement between the wall structure and veneer. Differential movement between the backup wall and veneer will also vary dependent on the backup wall type as described below.

CMU/Concrete

In CMU and concrete wall structures, shrinkage will occur over time due to initial drying and carbonation.

Steel Stud-Framed

In the support system, the steel stud-framed backup wall will experience little volume change; however, some movement may occur where studs interface with floor and roof lines.

Wood-Framed

In the support system, the wood stud-framed members will shrink due to moisture loss. Shrinkage is most concentrated at floor lines. 

Differential movement (between the structure and the veneer) in the vertical direction is accommodated with a horizontal gap between the veneer and elements that are directly attached to the wall structure, such as shelf angle supports, parapet top blocking, and windows. A backer rod and sealant or compressible filler placed within these gaps prevents insects and debris from entering the air cavity. 

Differential movement in the horizontal direction, often between the veneer and penetrations or different cladding materials is accommodated with a vertical joint through the anchored masonry veneer. Vertical gaps minimize stresses between the veneer and other components to provide crack control for the masonry veneer. Vertical gaps are typically sealed with a backer rod and sealant.

Both horizontal and vertical joints are designed based on the amount of differential movement expected and the compression or expansion limitations of any sealant joint or filler within the gap. For additional discussion on locating movement joints and for best practice sealant joint guidelines, refer to Chapter 4

Typical locations of joints for the purposes of accommodating movement, drainage, and/or air cavity ventilation are identified with an asterisk (*) in the details located in this chapter. In general, a minimum gap dimension of 3 ⁄8 of an inch is recommended; however, it is the Designer of Record’s responsibility to appropriately locate and size all movement joints.

Veneer Products and Properties

There are several types of anchored masonry veneer products that may be used with this system. Those most typical within Colorado and southern Wyoming include facing brick made of clay or shale. Concrete facing brick and concrete masonry units are also used.

For facing brick made from clay or shale, use anchored veneer units that comply with ASTM C21612 and are severe weather (SW) grade. When using concrete facing brick, anchored veneer units are to comply with ASTM C1634.13 Hollow concrete masonry units used for veneer applications are typically 4 inches deep and comply with ASTM C90.14

Mortar designed for the anchored masonry veneer units is to conform to ASTM C27015 and be the appropriate type for the veneer application. Type N mortar is acceptable for most anchored masonry veneer applications. Select the lowest compressive strength (softest) mortar that satisfies the project requirements to minimize stress on the anchored masonry veneer units, improve durability, and reduce initial cleaning efforts.

Appropriate product selection of masonry veneer unit and mortar materials is necessary to provide a durable and water-resistive cladding system. Install the masonry veneer units and mortar joints in conformance with industry-standard best practices and manufacturer requirements. Have a qualified Designer of Record design and review the specifics of architectural characteristics and structural properties of the masonry veneer units, mortar, and reinforcing.

Clear Water Repellents

Application of a clear water repellent to the anchored masonry veneer of this system is not common in Colorado and southern Wyoming. Where a clear water repellent is used, refer to the Surface-Applied Clear Water Repellents discussion in Chapter 4 for more information on selecting an appropriate clear water repellent and for best practice installation guidelines.

Quality Assurance and Control

High-quality masonry wall system installations are the result of quality control and quality assurance measures that occur throughout the design and construction phases. The general design guidance provided throughout this guide provides the information necessary for understanding and designing the anchored masonry wall system. More specifically, Chapter 5 provides a more in-depth discussion on the topic of quality assurance and quality control.

Chapter References

  1. International Code Council. 2018 International Building
    Code (Country Club Hills, IL: International Code Council,
    Inc., 2017).
  2. National Fire Protection Association. NFPA 285 – Standard
    Fire Test Method for Evaluation of Fire Propagation
    Characteristics of Exterior Non-Load-Bearing Wall
    Assemblies Containing Combustible Components (Quincy,
    MA: National Fire Protection Association, 2012).
  3. The Masonry Society. TMS-402/602-16 Building Code
    Requirements and Specification for Masonry Structures (n.p.:
    The Masonry Society, 2016).
  4. American Society of Civil Engineers. Minimum Design Loads
    for Buildings and Other Structures, ASCE/SEI 7-10 (Reston,
    VA: ASCE Press, 2013).
  5. ASTM International. ASTM A153/A153M-16a Standard
    Specification for Zinc Coating (Hot-Dip) on Iron and Steel
    Hardware (West Conshohocken, PA: ASTM International,
    2016).
  6. ASTM International. ASTM A580/A580M-16 Standard
    Specification for Stainless Steel Wire (West Conshohocken,
    PA: ASTM International, 2016).
  7. ASTM International. ASTM A123/A123M-15 Standard
    Specification for Zinc (Hot-Dip Galvanized) Coatings on
    Iron and Steel Products (West Conshohocken, PA: ASTM
    International, 2015).
  8. ASTM International. ASTM A666-15 Standard Specification
    for Annealed or Cold-Worked Austenitic Stainless Steel
    Sheet, Strip, Plate, and Flat Bar (West Conshohocken, PA:
    ASTM International, 2015).
  1. ASTM International. ASTM A653/A653M-15e1 Standard
    Specification for Steel Sheet, Zinc-Coated (Galvanized)
    or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-
    Dip Process (West Conshohocken, PA: ASTM International,
    2015).
  2. ASTM International. ASTM A792/A792M-10(2015)
    Standard Specification for Steel Sheet, 55% Aluminum-Zinc
    Alloy-Coated by the Hot-Dip Process (West Conshohocken,
    PA: ASTM International, 2015).
  3. American Architectural Manufacturers Association. AAMA
    621-02 Voluntary Specification for High-Performance
    Organic Coatings in Coil-Coated Architectural Hot-Dipped Galvanized (HDG) and Zinc-Aluminum Coated
    Steel Substrates (Schaumburg, IL: American Architectural
    Manufacturers Association, 2002).
  4. ASTM International. ASTM C216-17 Standard Specification
    for Facing Brick (Solid Masonry Units Made from Clay
    or Shale). (West Conshohocken, PA: ASTM International,
    2017).
  5. ASTM International. ASTM C1634-16 Standard Specification
    for Concrete Facing Brick (West Conshohocken, PA: ASTM
    International, 2016).
  6. ASTM International. ASTM C90-16a Standard Specification
    for Loadbearing Concrete Masonry Units (West
    Conshohocken, PA: ASTM International, 2016).
  7. ASTM International. ASTM C270-14a Standard Specification
    for Mortar for Unit Masonry

CMU BACKUP WALL: Window Head Detail

Detail 6-1 CMU Backup Wall
Detail 6-1 CMU Backup Wall

Legend

  1. Typical Assembly: – Single-wythe CMU wall – Faced rigid board insulation – Air cavity – Anchored masonry veneer 
  2. Masonry veneer anchor 
  3. Mortar collection mesh 
  4. Fluid-applied air barrier and WRB flashing membrane
  5. Hot-dipped galvanized-steel loose lintel 
  6. Vent/weep at maximum 24 inches on-center 
  7. Self-adhered flashing lapping on a sheet metal flashing with end dams (beyond) 
  8. Continuous blocking anchored to structure for window support and attachment 
  9. Sealant over backer rod 
  10. Continuous air barrier sealant tied to continuous seal at window perimeter 
  11. Storefront window, align thermal break with rigid board insulation
Water-Shedding Surface and Control Layers of Detail 6-1
Water-Shedding Surface and Control Layers of Detail 6-1

Detail Discussion

The window in this series of details is aligned with the adjacent insulation to minimizing thermal bridging around the rough opening at the window-to-wall interface. 

A self-adhered flashing membrane transitions from the face of the insulation to the sheet-metal flashing. This allows water at the face of the insulation (the water control layer) to drain to the exterior through the vent/weep. A self-adhered flashing is used in lieu of a sheet-metal flashing; a sheet-metal flashing would require additional blocking, and less insulation, at the rough opening head for attachment.

Water-Shedding Surface & Control Layers

Water-Shedding Surface & Control Layers
Note: Control layers are shown for a Class I or II faced rigid insulation board product.

CMU BACKUP WALL: Window Sill Detail

Detail 6-2 CMU Backup Wall: Window Sill Detail
Detail 6-2 CMU Backup Wall: Window Sill Detail

Legend

  1. Typical Assembly:
    – Single-wythe CMU wall
    – Faced rigid board insulation
    – Air cavity
    – Anchored masonry veneer 
  2. Storefront window, align thermal break with rigid board insulation 
  3. Sealant over backer rod 
  4. Continuous blocking anchored to structure for window support and attachment 
  5. Drainage matrix 
  6. Sloped precast sill with chamfered drip edge and sealant over backer rod at precast joints 
  7. Intermittent structural support for precast sill (beyond) 
  8. Masonry veneer anchor 
  9. Continuous air barrier sealant tied to continuous seal at window perimeter 
  10. Back dam angle at sill, minimum 1 inch tall, fasten window through back dam angle 
  11. Fluid-applied air barrier and WRB flashing membrane
Water-Shedding Surface and Control Layers of Detail 6-2
Water-Shedding Surface and Control Layers of Detail 6-2

Detail Discussion

Intermittent attachments back to the structure may be required to support the sill element. These attachments require detailing with a fluid-applied or self-adhered flashing membrane where they project through the insulation and facer. Intermittent attachments disrupt the insulation (thermal control layer) less than continuous attachments and are preferred. 

The drainage matrix behind the sill element allows for a continuous pathway for water to drain from the window rough opening into the air cavity below where it can be redirected exterior of the masonry veneer. This allows for a backer rod and sealant joint at the window perimeter to maintain a continuous water-shedding surface.

Water-Shedding Surface & Control Layers

Water-Shedding Surface & Control Layers
Note: Control layers are shown for a Class I or II faced rigid insulation board product.

CMU BACKUP WALL: Window Jamb Detail

Detail 6-3 CMU Backup Wall: Window Jamb Detail
Detail 6-3 CMU Backup Wall: Window Jamb Detail

Legend

  1. Typical Assembly:
    – Single-wythe CMU wall
    – Faced rigid board insulation
    – Air cavity
    – Anchored masonry veneer 
  2. Storefront window, align thermal break with rigid board insulation 
  3. Sealant over backer rod 
  4. Continuous blocking anchored to structure for window support and attachment 
  5. Fluid-applied air barrier and WRB flashing membrane 
  6. Masonry veneer anchor 
  7. Continuous air barrier sealant tied to continuous seal at window perimeter
Water-Shedding Surface and Control Layers of Detail 6-3
Water-Shedding Surface and Control Layers of Detail 6-3

Detail Discussion

Wood blocking shown at the jamb serves as a nailer to attach the window. Air and water control layer continuity between the window and wall is provided by a continuous seal and the fluid applied flashing membrane at the window rough opening perimeter. A brick return at the jamb may be needed to allow for the exterior backer rod and sealant to be installed. An air gap is to remain between the return brick and flashing membrane. It should not be packed with mortar.

Water-Shedding Surface & Control Layers

Water-Shedding Surface & Control Layers
Note: Control layers are shown for a Class I or II faced rigid insulation board product.

CMU BACKUP WALL: Base-of-Wall Detail

Detail 6-4 CMU Backup Wall: Base-of-Wall Detail
Detail 6-4 CMU Backup Wall: Base-of-Wall Detail

Legend

  1. Typical Assembly:
    – Single-wythe CMU wall
    – Faced rigid board insulation
    – Air cavity
    – Anchored masonry veneer 
  2. Masonry veneer anchor 
  3. Mortar collection mesh 
  4. Two-piece sheet-metal flashing with hemmed drip edge and end dams beyond, attached through the wood blocking 
  5. Fluid-applied air barrier and WRB flashing membrane 
  6. Vent/weep at maximum 24 inches on-center 
  7. Typical Assembly at Floor:
    – Concrete floor slab
    – Vapor barrier
    – Rigid XPS insulation
    – Capillary break 
  8. Rigid XPS insulation thermal break 
  9. Below-grade waterproofing or dampproofing with protection course where required 
  10. Continuous grout, sloped at top 
  11. Preservative treated wood blocking
Water-Shedding Surface and Control Layers of Detail 6-4
Water-Shedding Surface and Control Layers of Detail 6-4

Detail Discussion

In this detail, a thermal break is provided between the concrete floor slab and foundation element to minimize heat loss at the floor-to-wall interface. 

The bottom courses of masonry are at or below-grade; continuous grout exists behind the veneer for support. The sheet-metal flashing shown drains the wall cavity above to the exterior and stops the transfer of any moisture between the above- and below-grade masonry. 

Wood blocking shown serves as a nailer to attach the two-piece sheetmetal flashing.

Water-Shedding Surface & Control Layers

Water-Shedding Surface & Control Layers
Note: Control layers are shown for a Class I or II faced rigid insulation board product.

CMU BACKUP WALL: Roof Parapet Detail

Detail 6-5 CMU Backup Wall: Roof Parapet Detail
Detail 6-5 CMU Backup Wall: Roof Parapet Detail

Legend

  1. Typical Assembly:
    – Single-wythe CMU wall
    – Faced rigid board insulation
    – Air cavity
    – Anchored masonry veneer
  2. Inverted roof membrane assembly
  3. Precast cornice with chamfered drip edge
  4. Sealant over backer rod at precast joints beyond
  5. Sealant over backer rod
  6. Fully-reinforced fluid-applied roof flashing membrane
  7. Vents at maximum 24 inches on-center (optional)
  8. Masonry veneer anchor
  9. Split-tail anchor
  10. Cementitious-based waterproof coating

*Minimum 3⁄8-inch to allow for movement. Confirm dimension with Engineer of Record.

Water-Shedding Surface and Control Layers of Detail 6-5
Water-Shedding Surface and Control Layers of Detail 6-5

Detail Discussion

An application of cementitious-based waterproof coating is applied on the underside of the architectural precast concrete, cast stone, or limestone cap to minimize the migration of moisture below the cap area. This application can mitigate efflorescence in the wall below. 

The drip edge at the underside of the parapet cap encourages water to shed away from the enclosure before it can run down the face of the masonry cladding. This application can minimize staining and efflorescence. 

The thermal performance of this detail may be improved by framing and insulating the parapet as shown in Detail 6-13. The best approach for minimizing heat loss at the parapet is by insulating up and over the parapet structure.

Water-Shedding Surface & Control Layers

Water-Shedding Surface & Control Layers
Note: Control layers are shown for a Class I or II faced rigid insulation board product.

CMU BACKUP WALL: Roof Parapet 3D Detail

Detail 6-6 CMU Backup Wall: Roof Parapet 3D Detail
Detail 6-6 CMU Backup Wall: Roof Parapet 3D Detail

Legend

  1. Single-wythe CMU wall
  2. Faced rigid board insulation 
  3. Fluid-applied air barrier and WRB flashing membranes 
  4. Hot-dipped galvanized-steel loose lintel 
  5. Self-adhered flashing lapping on a sheet metal flashing with end dams (beyond) 
  6. Masonry veneer tie 
  7. Precast cornice with chamfered drip edge 
  8. High-temperature self-adhered membrane 
  1. Mortar collection mesh
  2. Anchored masonry veneer
  3. Inverted roof membrane assembly and roof structure
  4. Vents at maximum 24-inches on-center (optional)
  5. Storefront window
  6. Sealant over backer rod

Refer to Detail 6-1, Detail 6-3, and Detail 6-5 for more information.

CMU BACKUP WALL: Base-of-Wall 3D Detail

Detail 6-7 CMU Backup Wall: Base-of-Wall 3D Detail
Detail 6-7 CMU Backup Wall: Base-of-Wall 3D Detail

Legend

  1. Single-wythe CMU wall 
  2. Concrete foundation element 
  3. Fluid-applied or self-adhered flashing membrane 
  4. Two-piece sheet-metal flashing with hemmed drip edge and end dams beyond, attached through the wood blocking 
  5. Faced rigid board insulation 
  6. Mortar collection mesh 
  7. Fluid-applied air barrier and WRB flashing membrane 
  1. Anchored masonry veneer
  2. Storefront window
  3. Sloped precast sill with chamfered drip edge and sealant over backer rod at precast joints
  4. Vent/weep at maximum 24-inches on-center
  5. Continuous sealant and backer rod
Refer to Detail 6-2, Detail 6-3, and Detail 6-4 for more information.

STEEL STUD-FRAMED BACKUP WALL: Window Head Detail

Detail 6-8 Steel Stud-Framed Backup Wall: Window Head Detail
Detail 6-8 Steel Stud-Framed Backup Wall: Window Head Detail

Legend

  1. Typical Assembly:
    – Interior gypsum board
    – Vapor retarder
    – Steel stud-framed wall with batt insulation
    – Exterior sheathing
    – Self-adhered sheet- or fluid-applied air barrier and WRB field membrane
    – Semi-rigid exterior insulation
    – Air cavity
    – Anchored masonry veneer
  2. Masonry veneer anchor
  3. Mortar collection mesh
  4. Self-adhered sheet- or fluid-applied air barrier and WRB field membrane
  5. Hot-dipped galvanized-steel loose lintel
  6. Vent/weep at maximum 24 inches on-center
  7. Two-piece sheet-metal head flashing with hemmed drip edge and end dams (beyond)
  8. Sealant over backer rod
  9. Self-adhered sheet- or fluid-applied air barrier and WRB flashing membrane
  10. Non-flanged window
  11. Continuous air barrier sealant tied to continuous seal at window perimeter
  12. Window strap anchor, bed in air barrier sealant at continuous air barrier sealant joint plane

    A. See alternate shelf angle support detailing options on page 63

Water-Shedding Surface and Control Layers of Detail 6-8
Water-Shedding Surface and Control Layers of Detail 6-8

Detail Discussion

A non-flanged window is shown in the detail and facilitates future window replacement without the need to remove the anchored masonry veneer or window flanges. 

The intermittent strap anchors used to attach the window to the structure are bed in sealant at the plane of the continuous air barrier sealant at the window perimeter. This allows the air and water control layer to be continuous between the window and rough opening flashing membrane behind strap anchors.

Water-Shedding Surface & Control Layers

Note: Control layers are shown for a Class I or II permeance air barrier and WRB field membrane.
Note: Control layers are shown for a Class IV permeance (and sometimes Class III permeance) air barrier and WRB field membrane and where a vapor retarder is located at the interior face of the framing.

STEEL STUD-FRAMED BACKUP WALL: Window Head Detail

Detail 6-8 Steel Stud-Framed Backup Wall: Window Head Detail
Detail 6-8 Steel Stud-Framed Backup Wall: Window Head Detail

Legend

  1. Typical Assembly:
    – Interior gypsum board
    – Vapor retarder
    – Steel stud-framed wall with batt insulation
    – Exterior sheathing
    – Self-adhered sheet- or fluid-applied air barrier and WRB field membrane
    – Semi-rigid exterior insulation
    – Air cavity
    – Anchored masonry veneer
  2. Masonry veneer anchor
  3. Mortar collection mesh
  4. Self-adhered sheet- or fluid-applied air barrier and WRB field membrane
  5. Hot-dipped galvanized-steel loose lintel
  6. Vent/weep at maximum 24 inches on-center
  7. Two-piece sheet-metal head flashing with hemmed drip edge and end dams (beyond)
  8. Sealant over backer rod
  9. Self-adhered sheet- or fluid-applied air barrier and WRB flashing membrane
  10. Non-flanged window
  11. Continuous air barrier sealant tied to continuous seal at window perimeter
  12. Window strap anchor, bed in air barrier sealant at continuous air barrier sealant joint plane

    A. See alternate shelf angle support detailing options on page 63

Water-Shedding Surface and Control Layers of Detail 6-8
Water-Shedding Surface and Control Layers of Detail 6-8

Detail Discussion

A non-flanged window is shown in the detail and facilitates future window replacement without the need to remove the anchored masonry veneer or window flanges. 

The intermittent strap anchors used to attach the window to the structure are bed in sealant at the plane of the continuous air barrier sealant at the window perimeter. This allows the air and water control layer to be continuous between the window and rough opening flashing membrane behind strap anchors.

Water-Shedding Surface & Control Layers

Note: Control layers are shown for a Class I or II permeance air barrier and WRB field membrane.
Note: Control layers are shown for a Class IV permeance (and sometimes Class III permeance) air barrier and WRB field membrane and where a vapor retarder is located at the interior face of the framing.

STEEL STUD-FRAMED BACKUP WALL: Window Sill Detail

Detail 6-9 Steel Stud-Framed Backup Wall: Window Sill Detail
Detail 6-9 Steel Stud-Framed Backup Wall: Window Sill Detail

Legend

  1. Typical Assembly:
    – Interior gypsum board
    – Vapor retarder
    – Steel stud-framed wall with batt insulation
    – Exterior sheathing
    – Self-adhered sheet- or fluid-applied air barrier and WRB field membrane
    – Semi-rigid exterior insulation
    – Air cavity
    – Anchored masonry veneer 
  2. Non-flanged window on minimum 1⁄4-inch thick intermittent plastic shims 
  3. Sealant over bond breaker 
  4. Sloped sheet-metal sill flashing with hemmed edge and end dams (beyond), attached to intermittent L-angle at window per window manufacturer recommendations 
  5. Sloped precast sill with chamfered drip edge and sealant over backer rod at precast joints 
  6. Anchored masonry veneer 
  7. Continuous air barrier sealant tied to continuous seal at window perimeter 
  8. Back dam angle at sill, minimum 1 inch tall, fasten window through back dam angle 
  9. Self-adhered sheet- or fluid-applied air barrier and WRB flashing membrane 
  10. Intermittent structural support for precast sill (beyond)
Water-Shedding Surface and Control Layers of Detail 6-9
Water-Shedding Surface and Control Layers of Detail 6-9

Detail Discussion

A non-flanged window is shown in the detail and facilitates future window replacement without the need to remove the anchored masonry veneer or window flanges. 

The intermittent strap anchors used to attach the window to the structure are bed in sealant at the plane of the continuous air barrier sealant at the window perimeter. This allows the air and water control layer to be continuous between the window and rough opening flashing membrane behind strap anchors.

Water-Shedding Surface & Control Layers

Note: Control layers are shown for a Class I or II permeance air barrier and WRB field membrane.
Note: Control layers are shown for a Class IV permeance (and sometimes Class III permeance) air barrier and WRB field membrane and where a vapor retarder is located at the interior face of the framing.

STEEL STUD-FRAMED BACKUP WALL: Window Jamb Detail

Detail 6-10 Steel Stud-Framed Wall: Window Jamb Detail
Detail 6-10 Steel Stud-Framed Wall: Window Jamb Detail

Legend

  1. Typical Assembly:
    – Interior gypsum board
    – Vapor retarder
    – Steel stud-framed wall with batt insulation
    – Exterior sheathing
    – Self-adhered sheet- or fluid-applied air barrier and WRB field membrane
    – Semi-rigid exterior insulation
    – Air cavity
    – Anchored masonry veneer 
  2. Non-flanged window 
  3. Sealant over backer rod 
  4. Self-adhered sheet- or fluid-applied air barrier and WRB flashing membrane 
  5. Minimum 1⁄2-inch drainage path, fill with free draining compressible filler 
  6. Masonry veneer anchor 
  7. Continuous air barrier sealant tied to continuous seal at window perimeter 
  8. Window strap anchor, bed in air barrier sealant at continuous air barrier sealant joint plane
Water-Shedding Surface and Control Layers of Detail 6-10
Water-Shedding Surface and Control Layers of Detail 6-10

Detail Discussion

The backer rod and sealant joint at the interior side of the window provides air and water control layer continuity from the window to the air barrier and WRB flashing membrane at the rough opening. Strap anchors, which interrupt this sealant joint, are bed in sealant to maintain continuity of the air and water control layer. 

In this detail the brick return at the jamb prevents the exterior insulation from extending up to the window. To improve the thermal performance of this interface, the exterior insulation can extend up to the window rough opening and a shallower brick return may be used. A sheet-metal jamb flashing (typically attached to the window with small clips) can be used to conceal the air cavity and insulation and provide continuity of the water-shedding surface.

Water-Shedding Surface & Control Layers

Note: Control layers are shown for a Class I or II permeance air barrier and WRB field membrane.
Note: Control layers are shown for a Class IV permeance (and sometimes Class III permeance) air barrier and WRB field membrane and where a vapor retarder is located at the interior face of the framing.

STEEL STUD-FRAMED BACKUP WALL: Floor Line Detail

Detail 6-11 Steel Stud-Framed Wall: Floor-Line Detail
Detail 6-11 Steel Stud-Framed Wall: Floor-Line Detail

Legend

  1. Typical Assembly:
    – Interior gypsum board
    – Vapor retarder
    – Steel stud-framed wall with batt insulation
    – Exterior sheathing
    – Self-adhered sheet- or fluid-applied air barrier and WRB field membrane
    – Semi-rigid exterior insulation
    – Air cavity
    – Anchored masonry veneer
  2. Self-adhered flashing membrane
  3. Mortar collection mesh
  4. Hot-dipped galvanized-steel standoff shelf angle support anchored on intermittent structural support
  5. Vent/weep at maximum 24 inches on-center
  6. Sheet-metal flashing with hemmed drip edge
  7. Sealant over backer rod
  8. Vent at maximum 24 inches on-center (optional)
  9. Self-adhered sheet- or fluid-applied air barrier and WRB flashing membrane, extend onto intermittent structural support
  10. Masonry veneer anchor

    A. See alternate shelf angle support detailing options on page 63 

*Minimum 3⁄8-inch to allow for movement. Confirm dimension with Engineer of Record.

Water-Shedding Surface and Control Layers of Detail 6-11
Water-Shedding Surface and Control Layers of Detail 6-11

Detail Discussion

See Shelf Angle Flashing Options on page 63 for alternative flashing solutions that may be used at the floor line. 

The use of a standoff shelf angle to support the anchored masonry veneer allows insulation to run continuously across the floor line and minimize thermal bridging. This minimizes heat loss at the floor line and can improve thermal comfort; it is more thermally efficient than a continuous shelf angle support as discussed in Chapter 8.

Water-Shedding Surface & Control Layers

Note: Control layers are shown for a Class I or II permeance air barrier and WRB field membrane.
Note: Control layers are shown for a Class IV permeance (and sometimes Class III permeance) air barrier and WRB field membrane and where a vapor retarder is located at the interior face of the framing.

STEEL STUD-FRAMED BACKUP WALL: Roof-to-Wall Detail

Detail 6-12 Steel Stud-Framed Wall: Roof-to-Wall Detail
Detail 6-12 Steel Stud-Framed Wall: Roof-to-Wall Detail

Legend

  1. Typical Assembly:
    – Interior gypsum board
    – Vapor retarder
    – Steel stud-framed wall with batt insulation
    – Exterior sheathing
    – Self-adhered sheet- or fluid-applied air barrier and WRB field membrane
    – Semi-rigid exterior insulation
    – Air cavity
    – Anchored masonry veneer
  2. Inverted roof assembly
  3. Masonry veneer anchor
  4. Self-adhered sheet- or fluid-applied air barrier and WRB flashing membrane, lapped over roof membrane termination and roof penetration flashing membrane
  5. Continuous rigid or semi-rigid exterior insulation over drainage composite
  6. Mortar collection mesh
  7. Interior furring for finish attachment
  8. Vent/weep at maximum 24 inches on-center
  9. Sheet-metal flashing with hemmed drip edge
  10. Hot-dipped galvanized-steel standoff shelf angle support anchored on intermittent structural support
  11. Roof penetration flashing membrane (per roof membrane manufacturer), extend onto structural support

    A. See alternate shelf angle support detailing options on page 63

Water-Shedding Surface and Control Layers of Detail 6-12
Water-Shedding Surface and Control Layers of Detail 6-12

Detail Discussion

The standoff shelf angle support at this transition allows for continuous thermal insulation across the roof and wall assemblies. 

Masonry wall system installation often precedes roof membrane installation and restricts future access for installation of the roof membrane and flashing components behind the standoff shelf angle. As a result, installation of a roof membrane prestrip and roof penetration flashing membrane at the concrete wall is needed prior to masonry wall system installation. The roof membrane manufacturer can provide recommended prestrip detailing. 

Water-Shedding Surface & Control Layers

Note: Control layers are shown for a Class I or II permeance air barrier and WRB field membrane.
Note: Control layers are shown for a Class IV permeance (and sometimes Class III permeance) air barrier and WRB field membrane and where a vapor retarder is located at the interior face of the framing.

STEEL STUD-FRAMED BACKUP WALL: Roof Parapet Detail

Detail 6-13 Steel Stud-Framed Wall: Roof Parapet Detail
Detail 6-13 Steel Stud-Framed Wall: Roof Parapet Detail

Legend

  1. Parapet Assembly:
    – Roof membrane
    – Exterior sheathing
    – Vented steel stud-framed wall
    – Exterior sheathing
    – Self-adhered sheet- or fluid-applied air barrier and WRB field membrane
    – Air cavity
    – Anchored masonry veneer
  2. Inverted roof membrane assembly
  3. Standing-seam sheet-metal coping with gasketed washer fasteners
  4. Vent at maximum 24 inches on-center (optional)
  5. Preservative-treated wood blocking
  6. High-temperature self-adhered membrane
  7. Compressible filler
  8. Masonry veneer anchor
  9. Closed-cell spray foam insulation

*Minimum 3⁄8-inch to allow for movement. Confirm dimension with Engineer of Record.

Water-Shedding Surface and Control Layers of Detail 6-13
Water-Shedding Surface and Control Layers of Detail 6-13

Detail Discussion

The vents shown in the top course of the anchored masonry veneer are optional and may be used to increase ventilation of air behind the brick cavity. As shown in this detail, the sheet-metal coping is held away from the face of the masonry so as not to block the vent. 

A compressible filler is used between the masonry veneer and parapet blocking to allow for a separation between the blocking and anchor masonry veneer while preventing insects and debris from entering the cavity behind the masonry veneer. 

Parapet cavity insulation provides continuity of the thermal control layer at the roof-to-wall transition.

Water-Shedding Surface & Control Layers

Note: Control layers are shown for a Class I or II permeance air barrier and WRB field membrane.
Note: Control layers are shown for a Class IV permeance (and sometimes Class III permeance) air barrier and WRB field membrane and where a vapor retarder is located at the interior face of the framing.

STEEL STUD-FRAMED BACKUP WALL: Parapet 3D Detail

Detail 6-14 Steel Stud-Framed Backup Wall: Parapet 3D Detail
Detail 6-14 Steel Stud-Framed Backup Wall: Parapet 3D Detail

Legend

  1. Steel stud-framed wall with batt insulation 
  2. Exterior sheathing 
  3. Concrete roof structure 
  4. Steel stud parapet framing 
  5. Closed-cell spray foam insulation plug 
  6. Sloped preservative-treated blocking 
  7. Self-adhered sheet- or fluid-applied air barrier and WRB field membrane 
  8. Self-adhered sheet- or fluid-applied air barrier and WRB flashing membranes 
  9. Masonry veneer anchor, fastened through air barrier sealant, fluid-applied flashing membrane, or self-adhered membrane patch per WRB system manufacturer recommendations 
  10. Two-piece sheet-metal head flashing with hemmed drip edge and end dams
  1. Semi-rigid exterior insulation 
  2. Hot-dipped galvanized-steel loose lintel 
  3. High-temperature self-adhered membrane 
  4. Anchored masonry veneer 
  5. Sloped standing-seam sheet-metal coping with gasketed washer fasteners 
  6. Inverted roof membrane assembly 
  7. Non-flanged window 
  8. Sheet-metal jamb trim 
  9. Mortar collection mesh

Refer to Detail 6-8, Detail 6-10, and Detail 6-13 for more information.

STEEL STUD-FRAMED BACKUP WALL: Base-of-Wall 3D Detail

Detail 6-15 Steel Stud-Framed Backup Wall: Base-of-Wall 3D Detail
Detail 6-15 Steel Stud-Framed Backup Wall: Base-of-Wall 3D Detail

Legend

  1. Steel stud-framed wall with batt insulation 
  2. Exterior sheathing 
  3. Concrete floor slab 
  4. Hot-dipped galvanized-steel standoff shelf angle support anchored on intermittent structural support 
  5. Self-adhered sheet- or fluid-applied air barrier and WRB field membrane 
  6. Masonry veneer anchor, fastened through air barrier sealant, fluid-applied flashing membrane, or self-adhered membrane patch per WRB system manufacturer recommendations 
  7. Semi-rigid exterior insulation 
  8. Sheet-metal flashing with hemmed drip edge 
  9. Mortar collection mesh 
  10. Anchored masonry veneer
  1. Non-flanged window
  2. Sloped precast concrete sill with sloped sheet-metal sill flashing 
  3. Vent/weep at maximum 24-inches on-center 
  4. Self-adhered sheet- or fluid-applied air barrier and WRB flashing membrane 
  5. Continuous air barrier sealant tied to continuous seal at window perimeter

Refer to Detail 6-9, Detail 6-10, and Detail 6-11 for more information

STEEL STUD-FRAMED BACKUP WALL: Saddle Flashing 3D Detail

Detail 6-16 Steel Stud-Framed Backup Wall: Saddle Flashing 3D Detail
Detail 6-16 Steel Stud-Framed Backup Wall: Saddle Flashing 3D Detail

Legend

  1. Inverted roof membrane assembly over concrete roof structure 
  2. Inverted roof membrane 
  3. Self-adhered or fluid-applied flashing membrane, lap over roof membrane termination, roof penetration flashing membrane, and parapet saddle flashing membrane 
  4. Self-adhered sheet- or fluid-applied air barrier and WRB field membrane 
  5. Parapet saddle flashing membrane, extend onto sloped parapet blocking beyond anchored masonry veneer wall face (above) 
  6. Semi-rigid mineral fiber exterior insulation 
  7. Hot-dipped galvanized-steel standoff shelf angle support on intermittent knife plates 
  8. Shelf angle knife plate support with roof penetration flashing membrane (per roof membrane manufacturer) 
  9. Mortar collection mesh
  1. Sheet-metal flashing with hemmed drip edge 
  2. Anchored masonry veneer 
  3. High-temperature self-adhered membrane, lap membrane over parapet saddle flashing membrane and roof membrane termination 
  4. Exterior sheathing 
  5. Closed-cell spray foam insulation within framed parapet 
  6. Sloped standing-seam sheet-metal coping, end dam at anchored masonry veneer face beyond 
  7. Sheet-metal counterflashing with spring lock inserted into mortar bed beyond, seal with a sanded sealant over backer rod
Refer to Detail 6-12 and Detail 6-13 for more information.

WOOD-FRAMED BACKUP WALL: Window Head Detail

Detail 6-17 Wood-Framed Backup Wall: Window Head Detail
Detail 6-17 Wood-Framed Backup Wall: Window Head Detail

Legend

  1. Typical Assembly:
    – Interior gypsum board
    – Vapor retarder
    – Wood-framed wall with batt insulation
    – Exterior sheathing
    – Mechanically attached air barrier and WRB field membrane
    – Air cavity
    – Anchored masonry veneer
  2. Masonry veneer anchor
  3. Mortar collection mesh
  4. Continuous air barrier sealant
  5. Insulated window header
  6. Hot-dipped galvanized-steel loose lintel
  7. Self-adhered sheet- or fluid-applied air barrier and WRB flashing membrane
  8. Vent/weep at maximum 24 inches on-center
  9. Sheet-metal head flashing with hemmed drip edge and end dams (beyond)
  10. Sealant over backer rod
  11. Continuous air barrier sealant tied to continuous seal at window perimeter
  12. Non-flanged window

    A. See alternate shelf angle support detailing options on page 63

Water-Shedding Surface and Control Layers of Detail 6-17
Water-Shedding Surface and Control Layers of Detail 6-17

Detail Discussion

A loose lintel is depicted in this detail; however, the structure support for the anchored masonry above the window could also be a shelf angle support attached back to the wood-framed structure. In this case, the shelf angle would be detailed similar to Detail 6-20. 

A continuous bead of air barrier sealant exists between the rough opening flashing and the mechanically attached air barrier and WRB field membrane to maintain air control layer continuity.

Water-Shedding Surface & Control Layers

Note: Control layers are shown for a Class I or II permeance air barrier and WRB field membrane.
Note: Control layers are shown for a Class IV permeance (and sometimes Class III permeance) air barrier and WRB field membrane and where a vapor retarder is located at the interior face of the framing.

WOOD-FRAMED BACKUP WALL: Window Sill Detail

Detail 6-18 Wood-Framed Backup Wall: Window Sill Detail
Detail 6-18 Wood-Framed Backup Wall: Window Sill Detail

Legend

  1. Typical Assembly:
    – Interior gypsum board
    – Vapor retarder
    – Wood-framed wall with batt insulation
    – Exterior sheathing
    – Mechanically attached air barrier and WRB field membrane
    – Air cavity
    – Anchored masonry veneer 
  2. Non-flanged window on minimum 1⁄4-inch thick intermittent plastic shims
  3. Sealant over backer rod 
  4. Minimum 1⁄8-inch thick intermittent shims behind sill flange for drainage 
  5. Minimum 1⁄8-drainage matrix behind precast sill for drainage 
  6. Sloped precast sill with chamfered drip edge and sealant over backer rod at precast joints 
  7. Self-adhered sheet- or fluid-applied air barrier and WRB flashing membrane 
  8. Intermittent structural support for precast sill (beyond), detail anchor through air barrier and WRB membrane per membrane manufacturer requirements 
  9. Continuous air barrier sealant tied to continuous seal at window perimeter 
  10. Back dam angle at sill, minimum 1 inch tall, fasten window through back dam angle
Water-Shedding Surface and Control Layers of Detail 6-18
Water-Shedding Surface and Control Layers of Detail 6-18

Detail Discussion

This guide recommends that a sheet-metal flashing is not placed below the precast sill. It can prematurely degrade the mortar bed beneath the precast sill. 

Air and water control layer continuity in this detail is achieved by sealing the window frame against the flashing membrane at the sill. The flashing membrane is adhered to the field membrane. 

Intermittent structural supports may be needed to support the sloped precast sill. Air and water control layer continuity should be considered at these supports; additional sealant and/or flashing membranes may be required.

Water-Shedding Surface & Control Layers

Note: Control layers are shown for a Class I or II permeance air barrier and WRB field membrane.
Note: Control layers are shown for a Class IV permeance (and sometimes Class III permeance) air barrier and WRB field membrane and where a vapor retarder is located at the interior face of the framing.

WOOD-FRAMED BACKUP WALL: Window Jamb Detail

Detail 6-19 Wood-Framed Backup Wall: Window Jamb Detail
Detail 6-19 Wood-Framed Backup Wall: Window Jamb Detail

Legend

  1. Typical Assembly:
    – Interior gypsum board
    – Vapor retarder
    – Wood-framed wall with batt insulation
    – Exterior sheathing
    – Mechanically attached air barrier and WRB field membrane
    – Air cavity
    – Anchored masonry veneer 
  2. Non-flanged window 
  3. Sealant over backer rod 
  4. Minimum 1⁄2-inch drainage path, fill with free-draining compressible filler 
  5. Self-adhered sheet- or fluid-applied air barrier and WRB flashing membrane 
  6. Masonry veneer anchor 
  7. Continuous air barrier sealant tied to continuous seal at window perimeter
Water-Shedding Surface and Control Layers of Detail 6-19
Water-Shedding Surface and Control Layers of Detail 6-19

Detail Discussion

A drainage pathway is maintained between the brick return and the flashing membrane at the rough opening. This pathway may be filled with a free-draining material such as semi-rigid mineral fiber insulation or drainage matrix. Avoid packing this cavity with mortar, which can transfer moisture from the masonry veneer to the flashing membrane and possibly the sheathing beneath. 

A non-flanged window is depicted in this set of details. Flanged windows may be used with masonry veneer but non-flanged window are often considered for the ease of future window removal and replacement. 

Where exterior insulation is used with a wood-framed backup wall condition, refer to the steel stud-framed details for similar detailing.

Water-Shedding Surface & Control Layers

Note: Control layers are shown for a Class I or II permeance air barrier and WRB field membrane.
Note: Control layers are shown for a Class IV permeance (and sometimes Class III permeance) air barrier and WRB field membrane and where a vapor retarder is located at the interior face of the framing.

WOOD-FRAMED BACKUP WALL: Floor Line Detail

Detail 6-20 Wood-Framed Backup Wall: Floor Line Detail
Detail 6-20 Wood-Framed Backup Wall: Floor Line Detail

Legend

  1. Typical Assembly:
    – Interior gypsum board
    – Vapor retarder
    – Wood-framed wall with batt insulation
    – Exterior sheathing
    – Mechanically attached air barrier and WRB field membrane
    – Air cavity
    – Anchored masonry veneer
  2. Continuous air barrier sealant
  3. Self-adhered sheet- or fluid-applied air barrier and WRB flashing membrane
  4. Mortar collection mesh
  5. Hot-dipped galvanized-steel standoff shelf angle
  6. Closed-cell spray foam insulation
  7. Vent/weep at maximum 24 inches on-center
  8. Sheet-metal flashing with hemmed drip edge
  9. Sealant over backer rod
  10. Vent/weep at maximum 24 inches on-center (optional)
  11. Self-adhered sheet- or fluid-applied air barrier and WRB flashing membrane
  12. Masonry veneer anchor

    A. See alternate shelf angle support detailing options on page 63 

*Minimum 3⁄8-inch to allow for movement. Confirm dimension with Engineer of Record.

Water-Shedding Surface and Control Layers of Detail 6-20
Water-Shedding Surface and Control Layers of Detail 6-20

Detail Discussion

See Shelf Angle Flashing Options on page 63 for alternative flashing that may be used at the window head condition. 

A continuous bead of air barrier sealant exists between the flashing membrane and the mechanically attached air barrier and WRB field membrane to maintain air control layer continuity.

Water-Shedding Surface & Control Layers

Note: Control layers are shown for a Class I or II permeance air barrier and WRB field membrane.
Note: Control layers are shown for a Class IV permeance (and sometimes Class III permeance) air barrier and WRB field membrane and where a vapor retarder is located at the interior face of the framing.

WOOD-FRAMED BACKUP WALL: Parapet Detail

Detail 6-21 Wood-Framed Backup Wall: Parapet Detail
Detail 6-21 Wood-Framed Backup Wall: Parapet Detail

Legend

  1. Typical Assembly:
    – Interior gypsum board
    – Vapor retarder
    – Wood-framed wall with batt insulation
    – Exterior sheathing
    – Mechanically attached air barrier and WRB field membrane
    – Air cavity
    – Anchored masonry veneer
  2. Conventional roof assembly
  3. Standing-seam sheet-metal coping with gasketed washer fasteners
  4. High-temperature self-adhered membrane
  5. Compressible filler
  6. Vents at maximum 24 inches on-center (optional)
  7. Masonry veneer anchor
  8. Closed-cell spray foam insulation
  9. Continuous air-barrier sealant between sheathing and mechanically attached air barrier and WRB field membrane
  10. Insect screen
  11. Preservative-treated wood blocking

*Minimum 3⁄8-inch to allow for movement. Confirm dimension with Engineer of Record.

Water-Shedding Surface and Control Layers of Detail 6-21
Water-Shedding Surface and Control Layers of Detail 6-21

Detail Discussion

At the roof parapet transition, the closed-cell spray foam insulation and the continuous bead of air barrier sealant provide continuity of the air control layer. Additionally, the closed-cell spray foam assists with vapor control at this transition. An alternative to the use of closed-cell spray foam insulation within the parapet is to provide a prestrip membrane below the parapet framing to transition the air control layer from the wall to the roof assembly. This requires the exterior sheathing to be broken at the parapet and the membrane installation to be coordinated with framing. 

A compressible filler is used between the masonry veneer and parapet blocking to allow for differential movement between the backup wall and masonry veneer while preventing insects and debris from entering the cavity behind the masonry veneer.

Water-Shedding Surface & Control Layers

Note: Control layers are shown for a Class I or II permeance air barrier and WRB field membrane.
Note: Control layers are shown for a Class IV permeance (and sometimes Class III permeance) air barrier and WRB field membrane and where a vapor retarder is located at the interior face of the framing.

WOOD-FRAMED BACKUP WALL: Base-of-Wall 3D Detail

Detail 6-23 Wood-Framed Backup Wall: Base-of-Wall 3D Detail
Detail 6-23 Wood-Framed Backup Wall: Base-of-Wall 3D Detail

Legend

  1. Wood-framed wall with batt insulation 
  2. Closed-cell spray foam insulation 
  3. Exterior sheathing 
  4. Self-adhered or fluid-applied flashing membrane 
  5. Sheet-metal flashing with hemmed drip edge over hot-dipped galvanizedsteel angle 
  6. Self-adhered or fluid-applied flashing membrane 
  7. Continuous air barrier sealant 
  8. Mechanically attached air barrier and WRB field membrane 
  9. Mortar collection mesh 
  10. Masonry veneer anchor, fastened through air barrier sealant, fluid-applied flashing membrane or self-adhered membrane patch per WRB system manufacturer recommendations
  1. Anchored masonry veneer
  2. Sealant over backer rod 
  3. Weep/vent at maximum 24-inches on-center 
  4. Self-adhered sheet- or fluid-applied air barrier and WRB flashing membrane 
  5. Continuous air barrier sealant tied to continuous seal at window perimeter

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