Hi all, six weeks ago I ocntracted with a guy to put cultured stone on the exposed portions of my new exposed walkout foundation. He put the stones right on the concrete and two weeks later they started falling off. Due to his schedule he’s only 1/3 of the way done with the job. He’s telling me that he’ll just “wash” the rest of the wall and apply the stones and they will stick. He’s proposing to use some sort of ocnstruction adhesive to replace the ones that have already fallen off the wall.
However I talked with two experienced masons (yes, I should have hired them first) who are telling me that ALL the stones need to be stripped off because you never know which ones are going to pop off (right now you can just barely touch some of them and they fall right off; others hardly budge). These two masons are telling me that the oil used to help the foudnation forms release from the concrete are making it tough for the stones to stick. They’re saying the whole foundation needs to be scrubbed with muriatic acid and then I can reapply the stones. They say mesh is not necessary.
What do you guys think? What would you do if it was your house?
Thanks, Rob
Replies
There are several reasons the stone didn't stick.
Could have been form oil, could have been simply a dirty foundation, could have been from applying the veneer over a warm/hot foundation wall and the foundation wicking the moisture out of the mortar, could have been not using the right type of mortar, could have bee not properly buttering the backs of the stones...
Could have been a lot of things.
Stripping the loose ones and leaving the still-adhered ones is an option, but success depends on what type of stone you're using. It's unlikely that the guy you're using will be able to successfully match mortar color from an existing section to a reapplied section if the stone does indeed have mortar lines.
Without seeing the job, or if it was my place, I'd strip the whole shebang, wash the walls, and start over. Again, leaving what's already tight on the wall depends on the type of stone you used and the faith you have in the installer to blend new with old.
Cultured stone has pretty simple, yet specific, installation instructions. Read and heed before you give the green light for the process to begin again. Also, consider calling the tech line of the company that manufactures the stone that you used. See what they have to say.
Also, a good technique is to install the stone from the top down. That way mortar drips don't soil the stone below as they would if working bottom up, and when working top-down, the stones have to be buttered properly to stick without relying on support from below.
foudnation forms release from the concrete are making it tough for the stones to stick. They're saying the whole foundation needs to be scrubbed with muriatic acid and then I can reapply the stones. They say mesh is not necessary
All depends on what the CS mfgr shows on their installation destructions--some want stucco lath (mesh), some don't.
I'm not sure scrubbing with muriatic is the best choice, a PVA bonding agent might be simpler, especially after stripping the foundation of the mortar/thinset used.
I'm wondering if that's what's really the problem--what material was used to "stick" the CS on "with," it does make a difference, depending upon manufacturer.