I am designing a home with a wrap-around, covered front porch…about 10′ deep…and the finish surface is likely to be something like cracked tile or flagstone. I would like to have the space under the porch to be part of the basement and hope to make it somewhat like a “Charleston” basement…i.e., where enough of the basement is out of the ground so as to accomodate arched, operable casement windows as part of the means of ventilating/cooling the house.
My concern in moisture. I have read FH articles in which a second story porch was placed over living space but this detailing usually involved letting the water pass through the walking surface to a well-sealed, well-flashed sub-surface, the water draining off the surface though scuppers or the like.
In my case, I want the wear surface and the 5″ reinforced concrete one-way slab sub-structure to be integral and am thinking that some combination of concrete additives and some sort of elastomeric sealant over the concrete but before the tile/flagstone mortar or thin-set. Perhaps there is a material which will serve as both the sealant to the concrete AND the bedding for the tile/flagstone?? Of course this does not address the possibility of condensation on the inside, basement surface of the concrete…when the outside South Carolina air is hot and moist and the indoor air is cooler.
Your thoughts? Thanks for whatever you can offer.
Replies
We've done them with spancrete covered with a edpm membrane, concrete on top then stone. But I'm a carpenter not a concrete worker.
You might have a look at http://www.xypex.com.
-- J.S.
You beat me to it, John. I have not used it yet but it looks amazing. Recommended to me by a superb engineer.
I tested it on some stucco once. It works fine so long as there aren't any big cracks that it can't bridge.
-- J.S.
http://forums.taunton.com/tp-breaktime/messages?msg=75285.3
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