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MSV-GSP-001-25

Adhered Manufactured Stone Veneer

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Revised August 29, 2025

Section 047300

Note: This guide specification is for adhered manufactured stone veneer. This Section includes the term “Architect.” Edit this term as necessary to identify the design professional in the General Conditions of the Contract. The text must be edited by a qualified, licensed design professional to suit specific project requirements. CMHA makes no representations or warranties of any kind, expressed or implied, and disclaims any liability for damages resulting in the use of this guide construction specification.

The information contained in this guide specification is primarily based on the content in ASTM Specification C1780 and the Installation Guide and Detailing Options for Compliance with ASTM C1780 for Adhered Manufactured Stone Masonry Veneer, published by CMHA. Refer to those documents for additional information.

SECTION 04 73 00
MANUFACTURED STONE VENEER

PART 1: GENERAL

1.1 SECTION INCLUDES

  • A. Adhered manufactured stone veneer (MSV)
  • B. Installation materials
  • C. Accessories
  • A. Section 04 2000 – Unit Masonry
  • B. Section 09 2116 – Gypsum board assemblies – Cementitious backer board and gypsum sheathing.

1.3 REFERENCE STANDARDS:

  • A. ANSI A118.4 – American National Standard Specification for Modified Dry-Set Cement Mortar
  • B. ANSI A118.15 – American National Standard Specification for Improved Modified Dry-Set Cement Mortar
  • C. ASTM C140/C140M – Standard Test Method for Sampling and Testing Concrete Masonry Units and Related Units
  • D. ASTM C270 – Standard Specification for Mortar for Unit Masonry.
  • E. ASTM C847 – Standard Specification for Metal Lath
  • F. ASTM C933 – Standard Specification for Welded Wire Lath
  • G. ASTM C1670/C1670M – Standard Specification for Adhered Manufactured Stone Masonry Veneer Units
  • H. ASTM C1714/C1714M – Standard Specification for Preblended Dry Mortar Mix for Unit Masonry
  • I. ASTM C1780 – Standard Practice for Installation Methods for Cement-Based Adhered Masonry Veneer
  • J. ASTM D226/D226M – Standard Specification for Asphalt-Saturated Organic Felt Used in Roofing and Waterproofing
  • K. ASTM E2556/E2556M – Standard Specification for vapor Permeable Flexible Sheet Water Resistive Barriers Intended for Mechanical Attachment
  • L. Concrete Masonry & Hardscape Association (CMHA) Installation Guide and Detailing Options for Compliance with ASTM C1780 for Adhered Manufactured Stone Veneer Current Edition, (herein referred to as MSV Installation Guide)
  • M. CMHA MSV-TEC-001, Key Installation Checkpoints for Manufactured Stone Veneer
  • N. TMS 402/602-22 – Building Code Requirements and Specifications for Masonry Structures

1.4 ADMINISTRATIVE REQUIREMENTS:

  • A. Pre-Installation Meeting – General Contractor shall set pre-installation meeting at least two weeks prior to starting work from this section. Mock-up panel shall be complete and reviewed at this meeting.

1.5 SUBMITTALS:

  • A. Product data: Provide data for MSV units, lath and scratch coat or cement board, water resistive-barrier: and weep-screed/flashing materials.
    • a. Test Report for each MSV profile showing Compliance with ASTM C1670.
    • b. Color Charts (Stone, Trims, Pointing Mortar)
  • B. Detail Drawings: Per MSV Installation Guide or contractor can submit proposed detail drawings depicting proper installation and flashing techniques. Reference these details locations with those found on drawings.
  • C. Verification Samples: For each finish product specified, submit << one or __ >> sample board representing actual product, color, pattern and texture.

1.6 QUALITY ASSURANCE:

  • A. Manufacturer Qualifications: Company specializing in manufacturing the type of products specified in this section and a current producer member of the Concrete Masonry & Hardscape Association (CMHA).
  • B. Installer Qualifications: Contractors must be a “Certified MSV Installer” by the Concrete Masonry & Hardscape Association (CMHA) or document experience in projects of similar size and scope.

1.7 MOCK-UPS:

  • A. Construct mock-up panel minimum 4 feet long by 4 feet high: include <>. Demonstrate proper installation technique to be used on project.
    • a. Leave section exposed showing proper layering of WRB and Weep Screeds and Flashings.
    • b. See Part 3 – Execution paragraph 3.6 for laying pattern/style.
    • c. Mock-up shall remain on site until the work has been accepted.

1.7 DELIVERY, STORAGE AND HANDLING:

  • A. Store products in manufacturer’s unopened packaging until ready for installation.
  • B. Prevent damage and contamination by other materials.
  • C. Protect products from precipitation combined with freezing temperatures. Do not install products with visible frost or frozen moisture.
  • D. Protect Portland cement-based materials from moisture and humidity. Store under cover and off the ground and in a dry location.

1.8 FIELD CONDITIONS:

  • A. Cold & Hot Weather Requirements: Comply with requirements set by TMS 402/602. (Full set of requirements found in MSV Installation Guide)
  • B. Protect installation when temperature is 40° F or less prior to, during, and 48 hours after completion of masonry work per requirements set in TMS 602.
  • C. Protect installation from rapid drying when air temperature is greater than 100° F (or above 90° with a wind speed greater than 8 mph) prior to, during and 72 hours after completion of masonry work per requirements set in TMS 602.

1.9 WARRANTY:

  • A. See Section 01 7800 – “Closeout Submittals” for additional warranty requirements.

PART 2: PRODUCTS

2.1 ADHERED MANUFACTURED STONE MASONRY VENEER (MSV)

  • A. MSV units using a mixture of cement, lightweight aggregates, concrete additives and coloring pigments to replicate appearance of natural stone and designed to be applied with a cementitious mortar to a backing surface, complying with ASTM C1670/C1670M.
    • a. Color, Texture, range, Special Shapes: <> Provide manufactured corners for all outside corners.
    • b. MSV Trim: Provide <> as shown on drawings.
    • c. MSV Accessory Components: Provide <> as shown on drawings.

2.2 MORTAR MATERIALS:

  • A. Scratch Coat Mortars: Scratch coat mortars for applications directly to metal lath.
    • a. Site Mixed: ASTM C270 <> using the proportion method as specified in Section 040511.
    • b. Pre-Packaged/Preblended: ASTM C1714/C1714M <<Type N or Type S or ANSI 118.1
  • B. Setting Bed Mortar: Setting Bed used to adhere MSV units to scratch coat mortar or to bondable concrete or concrete masonry:
    • a. Prepackaged /Preblended Modified: ANSI A118.4: or A118.15 (Per TMS 402/602-22 Prescriptive Design Standards) Follow industry standards and manufacturers installation requirements for setting veneer.
  • C. Setting bed Mortar: Setting Bed used to adhere MSV units to cement board:
    • a. Prepackaged/Preblended thin-set Modified mortar <> Follow industry standards and manufacturers installation requirements for setting veneer.
  • D. Pointing Mortars: Pointing or Grouting mortars used to fill the joints between individual MSV units once the setting bed mortar has sufficiently cured:
    • a. Site-Mixed: ASTM C270 / ASTM C1714 Type N or S.
    • b. Approved pre-packaged pointing mortar that meets or exceeds standard.
    • c. Color: When specified, use iron oxide pigments to match color selected by architect.

2.3 ACCESSORIES:

  • A. Lath:
    • a. 2.5 lb/yd2 or heavier Self-furring metal lath (galvanized) meeting ASTM C847
    • b. Welded wire lath meeting ASTM C933
    • c. 18 Gauge (or heavier) woven wire lath meeting ASTM C1032
    • d. A lath product consistent with MSV Manufacturer’s installation instructions and evaluated by an accredited evaluation service showing compliance with ICC-ES Acceptance Criteria 275 (AC275) or equivalent and ASTM C1788.
  • B. Casing beads, Weep Screeds, and Trim accessories: ASTM C1861
    • a. PVC Color to be selected by Architect from standard colors.
  • C. Water-Resistive Barrier: sheet WRB meeting ASTM D226/D226M, Type I or ASTM E2556/E2556M Type I or II. Other acceptable materials include:
    • a. Materials evaluated for compliance with ICC-ES AC38.
    • b. Liquid-applied materials evaluated for compliance with ICC-ES AC212 (for use as primary WRB only)
    • c. Pre-Coated sheathing evaluated for compliance with ICC-ES AC310 (for use as primary WRB only)
  • D. Drainage system – When shown on drawings or required by code – drainage space or system noteless than 3/16 (5 mm) for drainage /ventilation. Minimum drainage efficiency of system 90 percent as measured by ASTM E2273 or E2925 Annex A2. When using entagled mesh, minimum compressive strength 15 psi.

PART 3: EXECUTION

3.1 EXAMINATION / ACCEPTANCE

  • A. Verify that backup wall system construction complies with MSV manufacturer’s instructions, CMHA MSV Installation Guide, CMHA MSV-TEC-001 and ASTM C1780.
  • B. Verify that substrates to receive mortar scratch coat or setting bed comply with MSV manufacturer’s instructions.
    • a. Scratch Coat: When scratch coat has dried before installing stone, dampen scratch coat by misting it with water to control suction. Visible water standing on the surface of the scratch coat will inhibit good bond. The scratch coat should be visibly hydrated but free from standing surface water.
    • b. Concrete Masonry Surfaces: Verify joints are cut flush and surface is ready to receive mortar setting bed. Verify no bituminous or water repellent coatings exist on masonry surface.
    • c. Concrete Surfaces: Verify surfaces are flat, honeycomb is filled flush, and surface is ready to receive mortar setting bed. Verify no bituminous, water repellent, or form release agents exist on concrete surface that are detrimental to mortar setting bed.
      • i. Surface must meet or exceed CSV level 2 or greater as set by International Concrete Repair Institute (ICRI) Technical Guide 310.2. When surface fails to meet level 2, attach metal lath per ASTM Standard.
    • d. Framing (Metal or Wood) w/ structural sheathing – Verify sheathing is installed per specifications. Follow manufacturer’s instructions when using sheathing that functions as the primary WRB layer.
    • e. Verify that related items provided under other sections are properly sized and located. These include roof kick-out flashings, chimney caps, wall copings and railings.
    • f. Verify that built-in items are in proper location and ready for installation of MSV units. This includes electrical outlet boxes, plumbing systems and other items shown on plans.

3.2 INSTALLATION – WATER RESISTIVE BARRIER

  • A. Integrate water-resistive barrier with all flashing accessories, adjacent water-resistive barriers, doors, windows, penetrations and cladding transitions.
  • B. For all sheet WRBs, install per manufacturer’s instructions, including proper lapping and transitions.
  • C. For all liquid and pre-coated sheathing: install per manufacturer’s instructions. Ensure flashing tape is properly installed over weep screeds/flashings prior to installation of secondary WRB.
  • D. WRB Installation Requirements
    • a. Light Frame Applications – install 2 two layers of WRB when using lath and scratch coat. Install one layer of WRB when using cement board.
    • b. Concrete/Masonry Substrate – installed WRB when indicated on drawings.

3.3 INSTALLATION – MASONRY FLASHINGS AND WEEP SCREED

  • A. As indicated on drawings, install masonry flashings, weep screeds and casing beads to divert water to the exterior at all locations (windows, doors, wall openings and base of wall) where the downward flow of moisture will be interrupted.
  • B. Butt end joints of flashing trim and seal watertight with flashing sealant/adhesive.

3.4 INSTALLATION – LATH

  • A. Install lath securely to surface with proper fasteners and spacing requirements.
    • a. Install fasteners into framing at required depth as outlined in MSV Design & Installation Guide.
    • b. Lap lath at vertical seams 1” minimum and at horizontal seams 1/2” minimum.
  • B. When installing lath over continuous insulation board refer to MSV Design and Installation Guide 5th Edition/5th Printing or later for proper fastener selection and required horizontal and vertical spacing required by International Building Code (IBC) based on insulation board thickness and assembly weight.

3.5 INSTALLATION – SCRATCH COAT / CEMENT BOARD

  • A. Metal Lath Surface:
    • a. Apply mortar scratch coat nominal ½” thick to completely cover and engage metal lath in accordance with ASTM C926. Scratch surface horizontally with scarifier when surface is thumb print hard.
    • b. When scratch coat has dried before installing stone, dampen scratch coat by misting it with water to control suction. If scratch coat is saturated, wait for surface to dry before installing stone veneer.
  • B. Cement Board:
    • a. Secure cement board to wall using required hi-low screws following manufacturers instructions. Screws should not exceed 8” vertical spacing.
    • b. Tape all seams with alkali-resistant adhesive mesh tape. Mud all seams with polymer thin-set mortar to embed mesh tape. For exterior applications use 4” minimum tape. For interior applications use 2” minimum tape. For all applications, use 4” minimum tape at all corners. Mud all seams with modified mortar meeting ANSI A118.4 or A118.15.

3.6 INSTALLATION – MSV

  • A. Install MSV with a cementitious mortar setting bed assuring complete coverage on back of stone surface in accordance with MSV manufacturer’s instructions, CMHA MSV-TEC-001 and ASTM C1780.
    • a. Work from multiple pallets / boxes to ensure proper color blending
    • b. Laying pattern should resemble approved Mock-up panel.
    • c. Mortar joints << Concave; Raked; Flush; Brushed; Extruded>> as approved in sample panel.
  • B. Sills/Water Table: Install sills where indicated on drawings. When detailed, secure metal support clips under stone sill prior to setting Sills/Water Table shapes.
  • C. For all exterior frame walls, install stone 4” above finish grade over soil conditions. Install stone 2” above pavement not supported by foundation.
  • D. Use accessory shaped stones around electrical boxes and other wall penetrations to ensure weather tight fit. When accessory shaped stones are not available, cut and fit stone around openings in a professional manner.
  • E. Install control joints/movement joints in stone veneer where indicated on drawings.
  • F. Remove excess mortar and mortar smears as work progresses.
  • G. Protect finished work from rain during and for 48 hours following installation.

3.7 TOLERANCES

Laying pattern demonstrated on Mock-up panel will be the standard for acceptance. In addition, proper workmanship should:

  • a. Maintain level horizontal coursing of stone pattern. Do not exceed variation from level greater than 1” in 20’.
  • b. Maximum variation of joint thickness should not exceed 1” for random stone patterns or as accepted on sample panel. Dry-set stone patterns should have tight fitted joints showing minimal variation.

3.8 CLEANING

  • A. Clean MSV in accordance with manufacturer’s installation instructions. Use non-metallic tools when cleaning MSV units.

3.9 SEALANTS/PROTECTIVE TREATMENTS

  • A. Apply flexible sealants in the color show on sample panel around all windows and doors.
  • B. Control joints – apply flexible sealant in all control joints in color shown on sample panel.
  • C. Protective treatments – While not required a protective treatment can help slow the absorption of water and make the MSV a little easier to clean. Only use either silane or siloxane breathable protective treatments. Follow protective treatment manufacturer recommendations. Test on sample stones or in an inconspicuous area.

3.10 PROTECTION

  • A. Protect finished work from staining or damage. Spread straw over bare soil to prevent mud stains.