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tropple · 09-30-2004, 10:15 AM

Hi,

A quick test:

Put a square of heavy, clear plastic on the concrete and then tape it on all edges with duct tape. If you see moisture under the plastic the next day, then water is migrating up through the concrete slab. Sounds odd, but it does. Concrete is porous and lets the moisture right through. Slowly, but it'll still come right through. If it's dry the next day, then:

Check the patio slab to make certain that it slopes away from the foundation. If it has settled such that the edge next to the foundation is lower than the outer edge, the water may flow down along the foundation and come through the cement blocks.

Very carefully, and with a very good light, check the joint between the patio and the foundation to verify that caulk along the joint is still intact. If there are any crack or it has pulled away from the patio slab or the foundation, then you will need to dig out that small (hopefully) portion of the caulk and apply new caullking. Frequently this area is caulk using a heavy tar/asphalt impregnated strip of material, though it could be some type of silicone or rubber material. If you need to recaulk, use GE Silicone II. If the gap is wider than a 1/4 inch or so, push some "backer rod" (a closed cell, hard foam rod that you can find at home depot near the air conditioner insulation kits, door thresholds, and foam weatherstripping) into the gap and then apply the caulk over that. Trying to fill a big gap using caulk is a bad idea.

PM or reply if you need more info.

09-30-2004, 10:15 AM	#2 (permalink)
tropple Junkie	Hi, A quick test: Put a square of heavy, clear plastic on the concrete and then tape it on all edges with duct tape. If you see moisture under the plastic the next day, then water is migrating up through the concrete slab. Sounds odd, but it does. Concrete is porous and lets the moisture right through. Slowly, but it'll still come right through. If it's dry the next day, then: Check the patio slab to make certain that it slopes away from the foundation. If it has settled such that the edge next to the foundation is lower than the outer edge, the water may flow down along the foundation and come through the cement blocks. Very carefully, and with a very good light, check the joint between the patio and the foundation to verify that caulk along the joint is still intact. If there are any crack or it has pulled away from the patio slab or the foundation, then you will need to dig out that small (hopefully) portion of the caulk and apply new caullking. Frequently this area is caulk using a heavy tar/asphalt impregnated strip of material, though it could be some type of silicone or rubber material. If you need to recaulk, use GE Silicone II. If the gap is wider than a 1/4 inch or so, push some "backer rod" (a closed cell, hard foam rod that you can find at home depot near the air conditioner insulation kits, door thresholds, and foam weatherstripping) into the gap and then apply the caulk over that. Trying to fill a big gap using caulk is a bad idea. PM or reply if you need more info. __________________ +++++++++++Boom!