Stucco over stone
Existing stone walls did have a stucco coating at one time, walls have been sandblasted. Looking for suggestions on proper application of installing new 3 coat stucco system. Interested in mixing formula for first coat to be a slurry coat and how long to let dry before next coat to racks are be applied.
We have stuccoed over stone before using chemical bonders in the scratch coat. The chemical bonder people owe me big time for promoting their material. Usually, there were right many cracks after a year or so. I think because stones expand and contract far differently than cement mortar. We have done this mostly on historic work, and it didn't seem to matter. We never had any stucco over stone fail to bond. I never did buy that mortar will always bond to a clean stone. Without acrylic, this could fail.
We mixed our cement mortar as usual, with half and half acrylic and water.
You can even dash on a scratch coat if the surface is real rough.
Here is our scratch coat with bonding admixture over flagstones.
Mortar with acrylic has very little suction. After you let this scratch coat set up at least overnight, you may want to put on a second scratch coat with regular mortar and let it set at least overnight, 2 days in cold weather.