ADHERED MASONRY VENEER SYSTEMS

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1 ADHERED MASONRY VENEER SYSTEMS Old Problems and New Challenges Robert C. Haukohl, PE The Masonry Society is a registered Provider with the American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to CES Records for AIA members. Certificates of completion for non-aia members are available upon request. This program is registered with AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation. 2 1

2 COURSE DESCRIPTION Adhered masonry veneer systems have continued to evolve since becoming popular in the 1950 s, with standards and installation guides trailing but eventually catching up. Now, energy codes and drainage plane requirements present new challenges for designers and installers, with old (yet still very relevant) concerns about durability and construction practices continuing to haunt the industry. This presentation will cover the basics about adhered masonry veneer, its comparative advantages and disadvantages, and ways in which the industry is trying to cope with old problems and new challenges. LEARNING OBJECTIVES Types of adhered masonry veneer Comparative advantages and disadvantages Design standards and installation guides Common problems with adhered masonry veneer New challenges Conclusions and recommendations 2

3 ADHERED MASONRY VENEER MASONRY That which is built by a mason; anything constructed of the materials used by masons, such as stone, brick, tiles, or the like. Masonry Contractors Association of America (MCAA) ADHERED VENEER Masonry veneer secured to and supported by the backing through adhesion. TMS 402 TYPES OF ADHERED MASONRY VENEER Thin Set (direct applied with no lath) Thick Set (with metal lath) Panelized (proprietary metal panel systems) Prefabricated panels (manufactured panels) Prefabricated panels (cast panels) 3

4 THIN SET ON CMU UNIT MASONRY BOND COAT CMU THIN SET ON STUDS UNIT MASONRY BOND COAT CEMENT BOARD BUILDING PAPER WRB SHEATHING 4

5 THICK SET ON CMU UNIT MASONRY BOND COAT SCRATCH COAT METAL LATH CMU THICK SET ON STUDS UNIT MASONRY BOND COAT SCRATCH COAT METAL LATH BUILDING PAPER WRB SHEATHING 5

6 THICK SET ON STUDS THICK SET ON STUDS 6

7 THICK SET ON STUDS THICK SET ON STUDS 7

8 THICK SET ON STUDS THICK SET ON STUDS 8

9 PANELIZED SYSTEM UNIT MASONRY ADHESIVE METAL PANEL BUILDING PAPER WRB SHEATHING PANELIZED SYSTEM 9

10 PANELIZED SYSTEM Photo courtesy of BIA PANELIZED SYSTEM 10

11 PREFABRICATED - MANUFACTURED PANEL BUILDING PAPER SHEATHING PREFABRICATED - MANUFACTURED 11

12 PREFABRICATED MANUFACTURED PREFABRICATED - MANUFACTURED Photo courtesy of BIA 12

13 PREFABRICATED - CAST Photo courtesy of BIA PREFABRICATED CAST 13

14 PREFABRICATED - CAST BASIC COMPONENTS OF ADHERED MASONRY VENEER SYSTEMS Backing / Substrate Concrete CMU Existing masonry Wood studs / sheathing Steel studs / sheathing Weather Resistive Barrier (WRB) Air barrier / vapor barrier Rigid insulation Cement board Metal lath / proprietary metal panel Mortar scratch coat and bond coat Unit masonry Thin brick Tile Natural stone Manufactured units ( cast stone or cultured stone ) 14

15 ADVANTAGES Inexpensive relative to traditional masonry Thin profile Lighter weight Versatile Can be installed by moderately skilled craftsmen Speed of installation Less material, energy, trucking to make the brick Can be panelized DISADVANTAGES Durability Sound ratings Fire ratings Inexpensive? Moderately skilled craftsmen? Conflicting installation requirements Challenges: Lack of a clear drainage plane Doesn t work well as a barrier system Doesn t work well with continuous insulation requirements. 15

16 CODES 2015 IBC Chapter 14 Exterior Walls Section Adhered masonry veneer WRB, flashing, thickness, hot/cold weather, stucco TMS Chapter 12 Veneer Section 12.3 Adhered Veneer Backing, thickness, weight, shear bond 50 psi (ASTM C482) BOND STRENGTH TMS Adhesion developed between adhered veneer units and backing shall have a shear strength of at least 50 psi (345 kpa) based on gross unit surface area when tested in accordance with ASTM C482, or shall be adhered in compliance with Article 3.3 C of TMS 602. TMS C Placing Adhered Veneer ASTM C482 Standard Test Method for Bond Strength of Ceramic Tile to Portland Cement Paste 16

17 STANDARDS ASTM C Standard Specification for Thin Veneer Brick Units Made From Clay or Shale ASTM C Standard Specification for Adhered Manufactured Stone Masonry Veneer Units ASTM C Standard Practice for Installation Methods for Adhered Manufactured Stone Masonry Veneer ASTM C Standard Guide for Selecting, Design, and Installation of Dimension Stone Attachment Systems [natural thin stone] ASTM C a Standard Specification for Installation of Lathing and Furring to Receive Interior and Exterior Portland Cement-Based Plaster THIN BRICK CLASSIFICATION ASTM C1088 Grades: Interior / Exterior Types: Type TBS (Standard) Thin veneer brick for general use in masonry. Type TBX (Select) Thin veneer brick for general use in masonry where a higher degree of precision and lower permissible variation in size than permitted for Type TBS is required. Type TBA (Architectural) Thin veneer brick for general use in masonry selected to produce characteristic architectural effects resulting from nonuniformity in size and texture of the individual units. When the type is not specified, the requirements for Type TBS will govern. 17

18 DESIGN AND INSTALLATION GUIDES BIA Tech Note 28C Thin Brick Veneer NCMA TEK 20-1 Key Installation Checkpoints for Manufactured Stone Veneer RMMI Adhered Natural Stone Veneer Installation Guide MVMA Installation Guide and Detailing Options for Compliance with ASTM C1780 for Adhered Manufactured Stone Veneer TCNA Handbook for Ceramic, Glass, and Stone Tile Installation BSI Natural Thin Stone Veneers NSVI Installation Guide and Helpful Tips IMI Seminar Adhered Masonry Veneer Systems ANSI A108 Installation of Ceramic Tile ILC Thin Veneer Installation Guide BE CAREFUL OF POSSIBLE CONFLICTS THERE ARE LOTS OF REFERENCES OUT THERE WHAT COULD GO WRONG? Freeze-thaw durability Veneer falls off Domino effect if one unit goes, the rest tend to follow Use of dry joints: susceptible to water intrusion Less than 100% coverage on back of masonry Skip the scratch coat and just apply daubs of mortar to back of brick: lick and stick Insufficient fastening of mesh Too few fasteners / fastener pull-through Materials not rated for wet environment Fiberboard backing Insufficient drainage / trapped moisture Doesn t work well as a barrier system Deteriorated backing Can t install below grade Can t rely on a surface seal Movement accommodation 18

19 Photo courtesy of FEMA 19

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26 Siding Window Trim Roof Batten Thin Brick Windows 26

27 Siding to Roof Window to Trim Trim to Siding Roof to Wall Siding to Batten Batten to Brick 27

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31 MOVEMENT JOINTS TMS 402: Design and detail the veneer to accommodate differential movement TMS 602: Indicate type and location of movement joints on the project drawings BIA Technical Note 28C: Extend movement joints through thickness of entire veneer assembly, for full length or height of veneer, including parapets Space no more than 18 ft. (5.5 m) o.c. in either direction Max. area between movement joints should not exceed 144 sq. ft. (13.4 m²) or length-to-height or height-to-length ratio of 2½ to 1 Align veneer movement joints directly over substrate movement joints For proprietary modular and prefabricated panels, follow manufacturer s instructions 31

32 NEW CHALLENGES Air barrier / vapor retarder requirements Adds another non-bonded layer Continuous insulation requirements Brings veneer farther away from substrate Drainage plane requirements Isn t the WRB enough? Where should these things be placed? It depends How do you detail these systems around openings Save for another presentation NEW CHALLENGES Air barrier / vapor retarder Goes on the warm in winter side of the insulation unless not used at all Continuous insulation requirements Can go inboard or outboard of CMU / studs Requires anchor design Drainage plane requirements Sometimes WRB isn t enough even a double layer Need a clear path to the drainage plane Need an unobstructed drainage plane Need a clear path to drain 32

33 THICK SET ON CMU WITH DRAINAGE MAT AND AIR BARRIER UNIT MASONRY BOND COAT SCRATCH COAT METAL LATH DRAINAGE MAT AIR BARRIER/WRB CMU THICK SET ON CMU WITH DRAINAGE MAT, AIR BARRIER, INSULATION UNIT MASONRY BOND COAT SCRATCH COAT METAL LATH DRAINAGE MAT CEMENT BOARD RIGID INSULATION AIR BARRIER/WRB CMU 33

34 THICK SET ON CMU WITH DRAINAGE MAT, AIR BARRIER, INSULATION UNIT MASONRY BOND COAT SCRATCH COAT METAL LATH RIGID INSULATION DRAINAGE MAT AIR BARRIER/WRB CMU THICK SET ON STUDS WITH DRAINAGE MAT UNIT MASONRY BOND COAT SCRATCH COAT METAL LATH DRAIANGE MAT BUILDING PAPER WRB SHEATHING 34

35 THICK SET ON STUDS WITH DRAINAGE MAT AND INSULATION UNIT MASONRY BOND COAT SCRATCH COAT METAL LATH DRAINAGE MAT CEMENT BOARD RIGID INSULATION WRB / BP SHEATHING THICK SET ON STUDS WITH DRAINAGE MAT AND INSULATION UNIT MASONRY BOND COAT SCRATCH COAT METAL LATH RIGID INSULATION DRAINAGE MAT WRB / BP SHEATHING 35

36 PANELIZED SYSTEM ON STUDS WITH DRAINAGE MAT UNIT MASONRY ADHESIVE METAL PANEL DRAINAGE MAT WRB / BP SHEATHING PANELIZED SYSTEM ON STUDS WITH DRAINAGE MAT AND INSULATION UNIT MASONRY ADHESIVE METAL PANEL DRAINAGE MAT CEMENT BOARD RIGID INSULATION WRB / BP SHEATHING 36

37 PANELIZED SYSTEM ON STUDS WITH DRAINAGE MAT AND INSULATION UNIT MASONRY ADHESIVE METAL PANEL RIGID INSULATION DRAINAGE MAT WRB / BP SHEATHING CONCLUSIONS Code requirements have made systems more complicated but despite the complexity it s still not impossible to design and build an energy efficient and functioning wall system Designers and contractors need to understand building code and manufacturers requirements. Don t use moisture sensitive materials. Is adhered masonry veneer still cost effective? 37

38 REFERENCES Brock, Linda. 11th International Brick/Block Masonry Conference. How Thin Is Too Thin? Economics and Durability of the New Thin Brick Veneer Systems, TCNA Handbook for Ceramic, Glass, and Stone Tile Installation. Tile Council of North America, Kwon, Renae, and Jean Wu. Adhered Masonry Veneer Systems: Understanding a Sticky Situation. Applicator, vol. 38.4, Fall Wigboldy, Jason. Attaching Lath for Adhered Masonry Veneer over Continuous Insulation: An Added Layer of Insulation Requires a Stronger and Corrosion Resistant Lath Fastener Whether for Traditional Three-Coat Stucco or Adhered Stone Veneer. Walls & Ceilings, 1 Feb. 2016, pp Building Science Institute. Natural Thin Stone Veneer Technical Information Guide. Elgin, Illinois, United States, Congress, Continuous Insulation Cladding/Furring Attachment Code Compliance Brief, U.S. Department of Energy. Filloramo, Richard, and Chris Bupp. Energy-Efficient Design with Masonry Construction. The Construction Specifier, 22 Oct Diqui, Jeff. Ensuring Moisture Protection for Manufactured Stone. The Construction Specifier, 4 Jan Bae/Mae, David H. Thin Stone Facade Problems and Causes of Failure. Failures, The Pennsylvania State University, 2012, failures.wikispaces.com/thin Stone Facade Problems and Causes of Failure. Foam Sheathing Coalition. Guide to Attaching Exterior Wall Coverings through Foam Sheathing to Wood or Steel Wall Framing. FSCTech Matters, 7 Dec Fechino, Steven. Pavers, Thin Brick and Stone, and Thin Veneer. Masonry Magazine, 28 Sept. 2015, Where's the Drainage Plane? On The Wall, vol. 20, no. 2, Fall 2010, Brian, Trimble E. The Emergence of Thin Brick: Understanding Adhered Veneer. The Construction Specifier, 29 June 2015, Wilson, Randy. Thin Brick When Is It the Right Approach? Masonry Design, masonrydesignmagazine.com/thin-brick/. QUESTIONS? 38