Telluride Stone Company
Preparing the Surface
Over sheetrock, wallboard, paneling, plywood, other rigid wood-related sheathing or rigid insulation board: cover the wall surface with a weather-resistive barrier. The barrier shall be equal to that provided for in the U.B.C. Standard No. 14-1
for kraft waterproof building paper of asphalt-saturated rag felt. The building paper or felt shall be applied horizontally with the upper layer lapped over the lower layer not less than 2 inches. Where vertical joints occur, the felt or paper
shall be lapped not less than 6 inches.
Then install 2.5 lb. (or heavier) diamond mesh expanded metal lath. Use galvanized lath for exterior applications. Black metal lath (non-galvanized) may be used for interior applications. Overlap lath sides by not less than 1/2″ and lath ends
by not less than 1 inch. Attach the lath using galvanized nails or staples 6″ on center vertically and 16″ on center horizontally, penetrating studs a minimum of 1.″ Be sure to attach the metal lath with the small cups pointing upwards. Wrap
metal lath a minimum of 16″ around all inside and outside corners, minimum to the next stud and do not break lath at the corner. Then apply a 1/2″-thick scratch coat of mortar over the metal lath and allow it to set. Mortar can either be type
N or S.
Over clean unpainted, unsealed, untreated brick, block, concrete or other masonry surfaces, no surface preparation is necessary.
Over painted, sealed or treated brick, block, concrete or other masonry surfaces must either a) be cleaned back to the original surface by sandblasting, water blasting, acid etching or wire brushing, or b) have metal lath attached using corrosion-resistant concrete nails with a scratch coat applied over the metal lath.