Chapter 5: Quality Control & Assurance

Chapter 5: Quality Control & Assurance2020-02-22T01:36:27-07:00
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Fig. 5-1 Douglas County Library in Lone Tree, CO
(Mason Contractor: Ammex Masonry, GC: Fransen Pittman General Contractors, Architect: AndersonMasonDale Architects) Photo by BrynMaRae

In almost all construction projects, quality control is the responsibility of the general contractor, whereas quality assurance is the responsibility of the design professional, third-party reviewer, or other designated entities. 

  • Quality Assurance: The Designer of Record or third-party reviewer is responsible for quality assurance during both the design and construction processes. During the project’s design phase, these entities develop standards and procedures to achieve a quality installation; these expectations are compiled into the construction documents. During the construction phase, the quality assurance role includes periodic review of construction to confirm that the installation complies with all aspects of the construction documents. The purpose of quality assurance review is to minimize installations that deviate from the project documents to deliver a high-quality final installation. 
  • Quality Control: The general contractor and subcontractors are responsible for performing quality control in the field. This entails a more comprehensive review of field work than that provided for by quality assurance. Quality control is the process of repeatedly executing every aspect of the construction in conformance with project documents and entails correcting deficiencies as they arise. The objective of quality control is to ensure all aspects of the final installation meets the project requirements. 

Quality control and quality assurance items impact the specification, construction, and evaluation phases of the masonry and its related wall components. Whereas this guide focuses on building enclosure design guidance and product selection of masonry materials, this chapter specifically focuses on recommendations for improving the masonry installation quality through aesthetic design considerations, through sample panels and mock-ups, and through field review of masonry installations.

Aesthetic Design Considerations

Consider the following during a project’s design phase to help develop a masonry wall system that meets the aesthetic expectations of the design and ownership team:

Fig. 5-2 Example of masonry texture during mid-afternoon; south elevation (left), east elevation (right)
Fig. 5-3 Example of light-colored masonry with dark mortar
Fig. 5-3 Example of light-colored masonry with dark mortar
Fig. 5-4 Example of light-colored masonry with similar colored mortar
Fig. 5-5 Example of slight shadows cast by sheet-metal and masonry reveals
  • How a building’s interaction with sunlight will affect the aesthetic of the masonry product.
    – Example: One side of a building is always shaded (from adjacent buildings/trees) vs. one side is always in direct sunlight (south-facing elevation in the summer). Fig. 5-1 Douglas County Library in Lone Tree, CO See Fig. 5-2.
  • The relationship between colors and textures of brick/ block and the color(s) and texture(s) of mortar.
    – Example: A mortar color that contrasts with the masonry, such as light brick and dark mortar as shown in Fig. 5-3, accentuates the masonry, including any imperfections. Mortar that compliments the masonry is likely to distract as shown in Fig. 5-4.
  • How profiles of flashings/drip edges affect aesthetics or reveals within the masonry coursing.
    – Example: Sheet-metal drip edges and reveals while affective for water shedding can also cast shadows. Sheet-metal flashing color and finish can also affect aesthetic. See Fig. 5-5.
  • How brick material composition and firing techniques can affect aesthetics.
    – Example: If minimal brick or concrete masonry unit (CMU) block color variations are desired for a project, units can be fired and supplied in one continuous run. This usually means that the initial order of masonry should be as accurate as possible, because manufacturers cannot always guarantee an exact match from subsequent runs.
    – Example: For CMU, the timing of the mold or formstripping during manufacturing impacts the color pigmentation and variation of color between units. Wider color variation is expected with smooth-faced units as opposed to split- or ground-faced units. 1
  • Acceptable criteria for unit color, texture, chips/cracks.
    – Example: Acceptable ASTM criteria may be used; however, the acceptable ASTM criteria may not be to a tolerance stringent enough for the architect and/or owner.
  • How finish mortar joint profiles will affect weathering.
    – Example: Concave or V-shape mortar joint profiles promote water shedding at the surface of the masonry; however, other profiles (e.g. grapevine, beaded, raked, etc.) may collect water and encourage efflorescence or increase the risk of freeze-thaw cycle decay. See Fig. 5-6.
  • How patterns can affect weathering.
    – Example: Stepping masonry (e.g., masonry not flush with adjacent units) can collect water and encourage efflorescence or increase the risk of freeze-thaw cycle decay. See Fig. 5-7.
Fig. 5-6 Concave mortar joint profile
Fig. 5-7 Example of stack bond with recessed brick

Sample Panels and Mock-Ups

Once the design aesthetic and performance requirements of the above-grade masonry wall system are established, the next quality assurance and quality control item is to demonstrate the masonry installation using sample panels or mock-ups. 

Sample panels and mock-ups are a visual representation of the project specification requirements. While not mandatory by code for all projects, this guide recommends sample panels for all masonry buildings as a critical component of quality assurance and quality control. Sample panels and mock-ups establish aesthetic and workmanship quality standards for reference throughout the project’s construction phase, benefiting the project schedule and budget. Sample panels and mock-ups also help to resolve conflicts in work quality, multi-trade coordination, and enclosure performance.

The minimum code requirements for sample panels are described by TMS 602-162 and are dictated by ASCE 7.3 Although code requirements for sample panels may vary per risk category, this guide recommends specifying and constructing a project-specific sample panel and/or a freestanding building enclosure mock-up to promote a quality masonry installation. 

This guide outlines three options for specifying and constructing a sample panel and rates them in order of Good, Better, and Best. Table 5-1 summarizes the key attributes of each option. The Good option is based solely on the minimum code requirements of TMS 602-16,2 while the Better option expands on these minimum requirements to include considerations for constructability and aesthetics. The Best option further identifies mock-up characteristics beneficial for aesthetics and building enclosure performance. 

Although this guide identifies additional considerations and specifications beyond the minimum code requirements for sample panel specification and construction, it is the discretion of the project owner and/or architect to incorporate any additional aesthetic and/or performance requirements into the project specifications.

Fig. 5-7 Example of stack bond with recessed brick

Good Option

A sample panel that remains as part of the final construction may be preferred by builders because it is more economical and typically accessible; however, should the project team find the work is unacceptable, removal of the sample work can damage the structure, enclosure components (e.g. flashing membranes), or other adjacent components. This damage may result in costly repairs or difficulty when reinstalling the sample panel.

The location of building sample panels should be carefully selected by the designer. The location of the sample panel on the building can hinder future accessibility for review or limit the designer’s ability to understand the material aesthetic because it is limited to one location on the project site.

When specifying a sample panel, it is the Designer of Record’s responsibility to reference the sample panel requirements outlined in Specification Section 1.6 D of TMS 602-162 as a baseline in developing sample panel specifications for their project. TMS 602-16 clarifies that the sample panel is to:

  • Be constructed from preapproved materials and methods.
  • Remain at the project site until the masonry work on the building has been accepted.
  • Establish the acceptable standard of work for the masonry construction on the building.
  • Be a minimum of 4 feet by 4 feet.
  • Demonstrate minimum site tolerances for the construction of the sample panel, as listed in Article 3.3 F of TMS 602-16.2
At minimum, TMS 602-16 also requires that the project specifications identify which person(s) or parties have the authority to accept, reject, and request modifications to the sample panel construction This guide recommends that the project specifications identify the formal process required to approve the panel should panel characteristics deviate from the contract documents.

Submittal Phase Requirements

Due to the lead time on sample panel materials, it is important that project specifications include submittal phase requirements for the sample panel. These requirements can help ensure that sample panel submittal requirements are clear, leaving ample time for the designer to review items and return approval of the items to the contractor. Although not required by TMS 602-16,2 this guide recommends that specifications require, at minimum:  
  • A specified number (e.g., 3 to 5) of full-size sample units be provided for each different type of masonry unit, representative of the approximate or full range of colors, textures, and dimensions expected in the completed construction.4
  • More than one mortar and surface coating product be ordered for sample panel construction. The final selection for mortar color and surface coatings will be made once several cured samples are on the constructed sample panel.5
  • Other accessory materials or products (e.g., reinforcement, anchors, sealants, and flashing membranes) are submitted for review and approved prior to constructing the sample panel. In general, all materials to be installed on the sample panel—except for mortar and surface coatings— must be approved before used in construction.5

Aesthetic Requirements

TMS 602-162 specification requirements are based on structural performance and do not explicitly address minimum requirements for the aesthetic quality of the masonry installation, though tolerances have some effect on the aesthetic. Thus, this guide recommends specifying minimum requirements for aesthetics prior to the bid phase to ensure project costs adequately represent the desired material aesthetic. Items include:
  • The size, grade, and type of the masonry units (including cell arrangement, where applicable).4
  • Product-specific specification for visible masonry accessories such as weeps, including desired color. If a substituted product may be considered, the specifications should contain a clause to address this process.
  • Industry standards for the appearance of masonry units. Example standards for brick include ASTM C2166 for facing brick, ASTM C6527 for hollow brick, ASTM C10888 for thin veneer brick, and ASTM C14059 for glazed brick. Example standards for CMU units include ASTM C5510 for concrete building brick, ASTM C9011 for loadbearing CMU, ASTM C12912 for nonloadbearing CMU, and ASTM C163413 for concrete facing brick. Use of industry standards establish the minimum acceptance criteria related to the appearance or aesthetic quality of the masonry upon shipment, including: chippage size and frequency, out-of-square, and warpage/distortion.14
  • Mortar joint profiles and tooling methods. This guide recommends concave or V-joint profiles to facilitate water shedding to increase long-term system performance.1
  • The minimum-expected level of work. For example, the specifier can require that the mock-up be built by a mason who has a minimum number of years’ experience and who will also be the mason doing the installation work on the larger project.

Material Performance Requirements

Minimum material performance requirements for the type or grade of masonry units, mortar, and other accessories used on a project are based on appropriate industry standards (e.g., ASTM, ANSI, and/or ACI standards). This ensures the products conform to the minimum and latest industry performance standards. Chapters 6 and 7 of this document further describe material performance requirements and reference standards.

Better Option

This approach provides the benefit of minimum disruption to the building structure if sample panel construction revisions are required. It allows the sample panel to be installed in an easily accessed location for continued reference and subcontractor training throughout the construction phase. The architect may also prefer the sample panel to be located where it is possible to view the panel in various sun exposure or adjacency conditions. 

In addition to the minimum submittal and material performance requirements and recommendations listed in the Good option above, additional aesthetic requirements may be incorporated into the project specifications.

Best Option

The Good and Better options described above are typically limited to 4×4 singular planes of installation; however, the best option recommended by this guide expands the sample panel installation into a larger construction of the full masonry system that requires multi-trade coordination. A full-system mockup can include the components of all the enclosure elements and adjacent or penetrating components, including, but not limited to:

  • Windows and/or doors, including rough opening detailing. 
  • Canopy attachments. 
  • Embedded flashing and trim elements. 
  • Expansion, control, and sealant joints. 
  • Typical penetrations, such as electrical and lighting.
  • Balcony and signage attachments. 
  • Transitions (e.g., roof-to-wall, inside/outside corners, etc.). 
  • Decorative or special architectural features.

The full-system mock-up incorporates the benefits of sample panel construction while considering adjacency of other building components in addition to the ability to perform building enclosure testing to confirm the performance of the enclosure elements for items such as water penetration resistance and air infiltration/exfiltration.

If a full-system mock-up is chosen, the project specifications need to be comprehensive and include all requirements of the mock-up system and the performance criteria. This guide recommends that the requirements of the mock-up are clear and fully documented prior to the bid phase and that the designer provide dimensioned drawings of the mock-up as part of the contract documents in addition to specifications. These supplementary provisions provide the trades with the adequate information to include an accurate scope of work in their bid documents, including labor and material estimates and the ability to plan for the time and cost of erecting the mockup. 15

Although additional aesthetic requirements, beyond those included with the Better option, are not necessarily included within this option, a mock-up will provide additional aesthetic confirmation for aspects such as masonry transitions at inside and outside corners, shelf angle supports, and transitions to other cladding types or components such as sheet-metal trim and wall penetrations.

Fig. 5-11 Freestanding mock-up undergoing water penetration resistance testing prior to cladding installation

Building Enclosure Performance Requirements

When using the Best option, this guide recommends outlining building enclosure-specific performance requirements in the project specifications. Often, the performance level of these requirements is determined with the assistance of the project’s building enclosure consultant.

For a freestanding full-system mock-up, there are numerous qualitative and quantitative tests used to evaluate the air infiltration/exfiltration and water penetration resistance of the building enclosure. Identification of potential leak paths during the mock-up allows for time to review project details or nonconforming work for revision or repair to reduce the risk for water penetration during the actual building service life.


Water penetration resistance testing, as shown in Fig. 5-11, is typically performed using the ASTM E110516 standard at an air pressure differential appropriate for the exposure and wind load on the building enclosure. This test method can identify leakage pathways such as at window rough openings or other penetrations within the primary water control layer of the enclosure.

The designer can also specify air infiltration/exfiltration testing of the building enclosure mock-up and its components including windows and doors. This test is becoming increasingly important where energy code requirements for airtightness are more stringent or energy performance goals are a high priority. An ASTM E78317 test is performed using specialized fan equipment and pressure gauges to determine the rate of air leakage through the mock-up. Using smoke tracers in conformance with ASTM E118618 may also help identify specific air leakage pathways that require rework.

This guide recommends specifying building enclosure performance testing to occur prior to the installation of any masonry veneer but following the installation of all penetrations and air, water, and thermal control layer materials. Although a more stringent test, this approach allows areas of air or water leakage to be readily identified during testing and to still be accessible should repair and/or reinstallation be required.

Field Review of Masonry Installations

The following evaluation items may be performed to ensure aesthetic quality of the masonry components or to ensure that system-specific building enclosure components conform to the project documents. These evaluation items may be performed on the sample panel or mock-up or through the course of construction. The aesthetic review for quality control items listed below apply to all systems in this guide, while building enclosure performance quality control items are provided individually, specific to anchored masonry and single-wythe CMU wall systems.

The items provided do not encompass structural review considerations, because these items extend beyond the scope of this guide; however, these items are equally as important for the long-term durability and safety of the masonry wall system installation. 

Aesthetic Review – All Systems

Review and evaluate the sample panel, mock-up, or wall:

  • When the panel/wall is clean and has been coated with required repellents or coatings and any surface-applied treatments are dry or fully cured.
  • Under diffused lighting. Non-diffuse lighting creates undesirable shadows and highlights flaws on the wall, giving a distorted visual appearance of the workmanship or materials.14
  • After colored mortar has had sufficient time to dry.5

Confirm the following when reviewing the sample panel, mockup, or field installation of anchored masonry veneer or singlewythe CMU wall systems:

  • The masonry materials and colors are represented in the sample panel and conform to the submitted and returned project submittals.
  • The sample panel includes intermixed or same-run brick or block representative; and a similar installation is performed on the building installation.
  • Modular coordination/pattern or cell arrangement complies with the architectural details.
  • Any variations within the field of the wall are acceptable to the designer
  • Mortar joint thicknesses are uniform and alignment of units are plumb and level.
  • The color, texture, and blending of masonry units; the relationship of mortar and sealant colors to masonry unit colors; the tooling of joints; the aesthetic qualities of workmanship; and other material and construction qualities meet the project specifications and designer/owner expectations.
  • Mortar joints are consistently tooled to the profile defined by the project requirements (e.g., concave or V-shape); and horizontal mortar joints (i.e., bed joints) are tooled before vertical joints (e.g., head joints) and are tooled when thumbprint-hard.
  • Control joints are spaced and located as defined by the project documents. Joints are free of debris and mortar and are of a thickness defined by the project documents.
  • Sheet-metal components are of the correct metal type, gauge, profile, and color/finish.

General Building Enclosure Review – Anchored
Masonry Wall System

The following evaluation items are system-specific to evaluating anchored masonry veneer. 

Review and evaluate the sample panel, mock-up, or wall area:

  • At a distance of 15 feet and under diffused lighting for FBX/HBX/TBX brick and at 20 feet for FBS/HBS/TBS and FBA/HBA/TBA brick per ASTM C216,6 ASTM C652,7 and ASTM C1088.8
  • At a distance of not less than 20 feet and under diffused lighting for CMU veneer per ASTM C1634.13

Confirm the following when reviewing the sample panel, mock-up, or any field installation of anchored masonry veneer.

  • The air cavity depth meets or exceeds the required depth.
  • The air cavity behind masonry veneer is kept free of mortar droppings and debris.
  • A mortar net is installed per the manufacturer requirements/ recommendations at the base of the veneer wall.
  • Flashing components are of the correct dimension, profile, slope, and material and are detailed at laps and transitions as required.
  • End dams are provided at sheet-metal terminations.
  • Flashing components within the wall are shingle-lapped into the water-resistive barrier (WRB) system and exit the veneer (to provide drainage).
  • Any sealing requirements at or above flexible membrane or sheet-metal flashing components, as required for air barrier system continuity, are provided.
  • Anchors and fasteners are the specified product and material finish (e.g. stainless steel or hot-dipped galvanized).
  • Anchor attachment penetrations through the air barrier and/or WRB system are detailed as required by the project documents and manufacturer requirements.
  • Mortar joints are of the specified profile type, well compacted, and free of voids at the surface.
  • Weep vents are located at the bottom course of veneer that bears on a bearing element. Weep vents are spaced as required and located tight to the bearing element (through the bed course). See page 68 for more information.
  • Vents (where required) exist in the top course of veneer and are spaced as required. Vents are staggered from weep vent locations directly above.
  • Exterior insulation of the correct thickness and type is installed continuously across the wall face and up tight to penetrations.
  • Exterior sealant joints at expansion joints and around penetrations are continuous, properly backed, appropriately dimensioned, and demonstrate an acceptable bond to the anchored masonry veneer and other substrates.
  • Exterior-applied clear water repellents are applied in conformance with the manufacturer installation instructions.

General Building Enclosure Review – Single-Wythe
CMU Wall System

The following evaluation items are system-specific to evaluating single-wythe CMU systems. 

Review and evaluate the sample panel, mock-up, or wall:

  • At a distance of not less than 20 feet, under diffused lighting, for load and nonloadbearing CMU per ASTM C9011 and ASTM 129.12
  • When all or a portion of the panel/wall is clean and has been coated with required clear water repellents or coatings and any surface-applied treatments are dry or fully cured.5

Chapter References

  1. National Concrete Masonry Association. TEK 5-16 Aesthetic Design with Concrete Masonry (Herndon, VA: National Concrete Masonry Association, 2011).
  2. The Masonry Society. TMS-402/602-16 Building Code Requirements and Specification for Masonry Structures (n.p.: The Masonry Society, 2016).
  3. American Society of Civil Engineers. Minimum Design Loads for Buildings and Other Structures, ASCE/SEI 7-10 (Reston, VA: ASCE Press, 2013).
  4. The Brick Industry Association. Technical Notes 11 Guide Specifications for Brick Masonry, Part 1 (Reston, VA: The Brick Industry Association, 2001).
  5. Concrete Products Group. “Using Sample Panels to Assure Project Quality.” Last accessed September 19, 2017. Video, 4:30, videos.
  6. ASTM International. ASTM C216-17 Standard Specification for Facing Brick (Solid Masonry Units Made from Clay or Shale). (West Conshohocken, PA: ASTM International, 2017).
  7. ASTM International. ASTM C652-17 Standard Specification for Hollow Brick (Hollow Masonry Units Made From Clay or Shale). (West Conshohocken, PA: ASTM International, 2017).
  8. ASTM International. ASTM C1088-17 Standard Specification for Thin Veneer Brick Units Made From Clay or Shale (West Conshohocken, PA; ASTM International, 2017).
  9. ASTM International. ASTM C1405-16 Standard Specification for Glazed Brick (Single Fired, Brick Units). (West Conshohocken, PA; ASTM International, 2016).
  10. ASTM International. ASTM C55-17 Standard Specification for Concrete Building Brick (West Conshohocken, PA; ASTM International, 2017).
  11. ASTM International. ASTM C90-16a Standard Specification for Loadbearing Concrete Masonry Units (West Conshohocken, PA: ASTM International, 2016).
  1. ASTM International. ASTM C129-17 Standard Specification for Nonloadbearing Concrete Masonry Units (West Conshohocken, PA; ASTM International, 2017).
  2. ASTM International. ASTM C1634-17 Standard Specification for Concrete Facing Brick (West Conshohocken, PA; ASTM International, 2017).
  3. Bronzella Cleveland. “Tech Talk: How To Look At A Brick Wall,” Masonry Magazine, published June 1, 2017, https://
  4. Alan Esche and Charles W. Ostrander, “Job Site MockUp Panel Qualifies the Bidders,” originally published in MasonryEdge/the StoryPole, n.d., Volume 4, Number 4. Republished by Masonry Advisory Council, last accessed September 19, 2017, wp-content/uploads/2016/06/Job-Site-Mock-ups-forBidders.pdf.
  5. ASTM International. ASTM E1105-15 Standard Test Method for Field Determination of Water Penetration of Installed Exterior Windows, Skylights, Doors, and Curtain Walls, by Uniform or Cyclic Static Air Pressure Difference (West Conshohocken, PA: ASTM International, 2015).
  6. ASTM International. ASTM E783-02 (2010), Standard Test Method for Field Measurement of Air Leakage Through Installed Exterior Windows and Doors (West Conshohocken, PA: ASTM International, 2010).
  7. ASTM International. ASTM E1186-17, Standard Practices for Air Leakage Site Detection in Building Envelopes and Air Barrier Systems (West Conshohocken, PA: ASTM International, 2017).

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