Surface Preparation
Clean Concrete, Brick and Block surfaces
No preparation is needed.
Newly poured concrete surfaces should be tested with water to ensure they are free from release agents (form oil). Water beading shows presence of release agents. To remove, rinse thoroughly with water and use a wire brush or use a high pressure washer. For major contamination acid treatments and/or sandblasting are also possible but we recommend you obtain professional advice.
For chimney stacks we advise application of a scratch coat with a water sealer in order to minimise water penetration.
Wood, Wood based sheeting, Plywood, Wallboard etc
A weather resistant barrier (breather membrane) such as waterproof building paper or asphalt saturated rag felt should be applied horizontally with the upper layer overlapping the lower layer by at least 50mm to 100mm. Vertical joints should overlap by at least 100mm to 150mm.
Interior stud walls should have a diamond mesh metal lath installed. Ensure that a galvanised metal lath is used for exterior installations. Apply 10mm to 12mm thick scratch coat of mortar over the metal lath and leave to set for approx 48 hours.
Painted, Sealed or Treated Brick, Block, Concrete or other Masonry Surfaces
The surface must either be cleaned back to the original surface (via water blasting, sandblasting, wire brushing or acid etching) or have a diamond mesh metal lath attached using corrosion-resistant concrete nails and a scratch coat then applied over the metal lath. A scratch coat is recommended to level any uneven surfaces.
Metal Panels
Surface preparation is as for wood based surfaces except that the diamond mesh metal lath should be attached with self-tapping screws ensuring 8mm to 10mm penetration beyond the inside metal surface.
Chimney or Bay Window at Lead Locations
Use a 50mm x 35mm timber batten (treated) to build out the lead, flush with the outer face of the stone thereby concealing the thickness of the stone.
Relevant information
Would you like to read more about our installation… download our installation guide.
© Viridian Stone
