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I need to pour a patio slab at finished floor level on a house with a basement. That means I must pour against a plywood wall against the floor joists. Any ideas on water proofing and termite proofing this area? How to keep out seepage, will aluminum flashing to the ground do it? How do I keep the slab from setteling later? Basement wall is poured concrete with a brick ledge, if I laid cap block on the ledge and went up to slab level how do I waterproof all this?
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Will there be a door out to the pad? It sounds like this home has soil right up to this same level , is this the case? If so ,its a problem already. I would get down as low as I could below the existing sill plate , lets say 1 1/2' or so. clean the wall perfectly. Install primers and epdm below and above grade, one piece, no seams. Install a barrier to protect epdm(I forget the product name it is similar to cedar breather) Install a french drain system along the wall. Then make sure your pad is pitched well from the wall.
*Got home late from a simple entry door change. Yeh right. Outer box and sill plate insect infested and rotten. Concrete stoop poured right against the rev. batten siding. If you don't do the flashing right and keep the moisture away you'll regret it. Best of luck.
*OK, I'll Bite.Height from brick ledge to finish floor must be somewhere around 15 to 18 inches, right? You already have ledge uncovered, right? Patio floor to be 4 to 6 inches thick?I would not tie in patio to basement wall. Patio will be above frost grade and may want to shift a little. If so, patio movement may cause wall to flex and possibly crack down the road; allowing water seepage. Instead of capping ledge, I too would clean wood joist band and wall as best as possible and attach epdm to both as earlier mentioned. I then would install 1 inch ridgid foam board (Dow Blue-board) down in front of wood wall and across the ledger area. Foam to be sliced in the back so board is "L" shape. Have foam extend 1 to 2 inches above finish floor height; score backside of foam approx 1 inch BELOW finish floor height. (This will allow you to easily take hold of the foam and snap it off after your concrete pour has set up; leaving you with a 1 inch square gap to be filled with either epoxy grout or hot tar. Regular caulking not good enough to use here.)Where the foam is sitting on the brick ledge, install a French drain in this location directly on top of foamboard. Make sure drain has protective sock cover so as not to silt up, and run drain line to "daylight" or tie in wherever. Use sand or gravel as your base to build up your gound to floor height for your patio slab. Pour base material right over top of drain line. Build this base up in compacted layers until it is the right height for your intended patio slab thickness. Entire patio area must have compacted gravel layers or sand, not just area next to basement wall. If to do so, you must first excavate, then excavate (nothing's ever easy!).Pour your slab. As I indicated, the foam will act as a isolation/expansion joint between your house and the new slab. Pouring in expoxy grout or hot tar should seal this joint to keep moisture out.I too would slope this patio away from the house so water will drain away. If you want added protection, you could install either a piece of aluminum flashing or a piece of vinyl garage door trim( cut on a 45 degree, and acting as a cant strip)to bridge overtop the epoxy/tar joint and further direct water away from this area. Unless for good reason, I would not pour slab to be same height as interior finished floor. I would allow at least a 1 inch drop. This way, water cannot back up into interior.Best way to keep concrete from settling is to have good drainage and a good compacted base underneath it. 1/2 inch rebar or 6X6 WWM for reinforcement is always a good idea as well. Chances are, it may still settle (drop) somewhat; another good reason to pour patio 1 inch lower than door threshold height....you won't notice minor changes in pad height.Good luck.Davo.
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I need to pour a patio slab at finished floor level on a house with a basement. That means I must pour against a plywood wall against the floor joists. Any ideas on water proofing and termite proofing this area? How to keep out seepage, will aluminum flashing to the ground do it? How do I keep the slab from setteling later? Basement wall is poured concrete with a brick ledge, if I laid cap block on the ledge and went up to slab level how do I waterproof all this?