We get asked a variety of Q’s on applications and best practices for stone installations on a regular basis.
Dean Cavicchi of Ardex Co. authored this and has a lot of field experience with these types of applications.
For Pool Copings, this is what we see for typical applications :
If the substrate is concrete you could go directly over the cleaned, porous concrete with X-32 or X-90, then set your stone. You can use AM-100 first if you need to prep the surface to make it flat.
If the substrate is PVC or metal you must rough up the surface with a heavy grit sandpaper, cleaning it thoroughly afterwards. Then you must key in some Ardex 8+9 with a 3/16” V- notch trowel and trowel and imbed the SK-mesh into it centering on the seam of PVC-metal-concrete. This may require more than one piece of mesh.
Let dry then apply second coat of 8+9.
Then install the coping with X-32 or X-90. The X-90 can be used but the substrate must be flat. If not set it with X-32 to account for the undulation.
If the PVC or metal are wide enough by themselves to support the coping you could skip above and use WA Epoxy Grout/Adhesive. This does not have the sag resistance of X-32 so shimming (plastic shims or wedges) may be required.
Use FH Grout to grout the coping and you must have soft joints every 8-12 feet or however the layout works out – to the closest grout joints. Use Ardex SX silicone caulking for this.