Detailing Wall Assembly to Manage Bulk Water
Hello, this is my first post. We purchased a house built in 1974 in zone 5A. To the exterior side it has painted, vertical cedar T&G siding (no air gap) backed by building paper and plywood. Foundation is 10″ wide poured concrete with a 4×6 bottom plate and 2×12 rim boards. I’ve not found information on how people are now handling this wall construction in renovation—if you are able, please direct me. OK, so the worst of it is the interface at wood and concrete. I have three leaking areas into the basement. Rim boards in bad shape; bottom plate condition unknown. I am looking for advice on how to handle where siding is attached to rim board, particularly at or below the level of the concrete foundation. In, other words, I don’t know how to finish at the bottom the vertical siding to protect from water and mice. Thank you, Bill
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First make sure grade slopes away from the foundation on all sides. If you're getting leaks, something is not properly shedding water out and away..
Gutters and downspouts and positive drainage first. Then come back to the siding and rim boards if you still have issues. If the siding and sill plate are not proud (outside) or flush to the outside face of foundation wall, you'll need to get a metal flashing on there tucked up and behind the building paper to shed water.
Thanks Jason. The house is built with the rim joists flush with the foundation. Except for one place where another, but treated, 2x6 must have been placed from the inside next to the original rim joist. It's scary to think what may be lurking behind this. You are correct to direct me to the slope from the house, and i need to correct any issues this spring. The leaks are at three places: two concrete porches, to accommodate the entry landing 2 doors, for which the foundation was "jutted" out from its normal rectangle so they could be supported on the foundation . The third is a deck cut out into the envelope of the house, so it's supported over my structural house framing. The water or most of it has to be coming from between the concrete and wood structure.
I do think you have answered a main worry of mine. I need to flash at the bottom of the siding to help remove water that gets through the siding irrespective of having an air gap. I don't know about getting behind the building paper to do that. Without disturbing anything perhaps I can tape over the flashing onto the paper where siding is removed. Having my mason over today, we looked at this 10 days to Sunday. I hate to say it, but removing the concrete deck surface and one landing will be the best way to go. Regards, Bill