NSVI FDL Stone Thin Veneer Installation Guide 2021

Interiors (Over Drywall)

• Instead of using moisture resistant barrier and wire mesh system, cement board products can be used for interiors. ( Exception : Interior water features require WRB.) • Apply cement board per manufacturer ’ s specifications over studs (drywall is not necessary if using min. 1/2” thick ce- ment board), but can be left in place). • Fasten cement board using corrosion resistant screws every 16” horizontally on center, and minimum 6” vertically, ensuring minimum 1 inch of wood stud penetration, or 1/2” penetration if applied over metal studs. • Tape cement board seams with fiberglass tape and seal seams with polymer modified mortar meeting ANSI 118.4, or ANSI 118.15. • Use mortar meeting ANSI 118.4 or 118.15 specifications for adhering stone to cement board. • Ensure surface is clean and free of debris. Cement Board — ( For exteriors, use cement board rated for exteriors, and refer to moisture control section on this page.) If drywall is used as the substrate, follow guidelines for Wire Lath/Mesh and Scratch - Coat as seen on this page. Then see, “ Applying NSVI Stone Veneer ” on page 5.

Getting Started (continued...)

Preparation Work Area

• Protect surfaces that could be damaged during the stone installation process, such as hardwood flooring, window trim, and other areas that have already been finished. • Stage material close to the installation area. Layout stones so they can be easily viewed and reached. It is important to obtain stones from multiple packages (boxes and/or crates ) and organize them by size, color, and texture. Opening all boxes and crates will facili- tate random distribution. Moisture Control • Flashing: Verify flashing is properly installed (roof, chimney, windows, door openings, etc.); should integrate with Water Resistive Barriers (WRB) • WRB: At least one layer followed by rainscreen or drainage plane. Install from bottom up, overlapping min. 4 inches, horizontally and vertically. • Weep Screeds: Should be applied per manufacturer ’ s specifications. Depending on product, may need additional fabric layer to ensure prod- uct from getting filled with scratch coat. Must be corrosion resistant, and terminate behind WRB. • Drainage Plane: A drainage wall system can be a design choice or a requirement of the local building code. • R E F E R T O L O C A L B U I L D I N G C O D E S Use expanded, galvanized, self - furring diamond - mesh meeting requirements of ASTM C847 - 18 (min 2.5 lb/yd 2 ). • Install tightly, cups up (smooth when felt from bottom to top, rough when felt top to bottom.) • Overlap sections of lath approximately 1 inch. • Fasten lath with corrosion resistant fasteners every 16” horizontally on - center, and maximum 6” vertically. • Wrap corners minimum 16” (inside and outside corners.) Wire Lath/Mesh •

Mortar Setting Bed (Adhesion Layer)

Type - S (ASTM C270) or polymer modified mortar should be used for Natural Stone Veneer products unless tight - fitting for no visible mortar joints (i.e. Ledgestone, or Dimensional Ledgestone Collections .) • Consistency of mortar mix is important. If too wet or too dry, mortar will not adhere to stone or substrate surface properly. It should stick to the trowel. • NSVI recommends adding acrylic bonding agent to Type - S mortar. This enhances the flexural, adhesion, compressive, and tensile strength qualities.

Polymer Modified Mortar

Thinset (ANSI 118.4, or ANSI 118.15) when tight - fitting NSVI stone (also see Pg. 6).

WOOD STUDS: If anchoring to wood studs with screws, use washers, and ensure 1 inch of stud penetration. If anchoring with wide - crown staples, ensure staples will penetrate 1 inch deep. STEEL STUDS: If anchoring to steel studs, ensure 1/2 inch of steel penetration beyond inside surface.

Scratch - Coat

• •

Ensure surface is clean and free of any debris.

Use Type - S mortar.

• It is important to not leave the scratch - coat surface smooth. Groove scratch - coat horizontally with a notched trowel or mason ’ s “ comb ”. • Scratch - coating can be done in its entirety before adhering stone, but it is also acceptable to “ scratch - as - you - go ”.

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