We have water leaking between the slab foundation and sill plate of our house. The home was built in 1980 and I do not believe a foam gasket was used under the sill. One obvious issue is that there is not adequate clearance between the bottom of the cedar siding and grass, which results in splashback onto the sill/foundation joint. We live in the Pacific Northwest with lots of rain, so this is certainly one of the issues. However, after grading the soil away from the home I’m wondering if flashing should be added to prevent water, insects or air drafts through the joint. I’ve read that some people use self adhering butyl or asphalt flashing, but in this case, the flashing would be left exposed to the weather since it would be partially adhered to the slab foundation. Wrong side vapor barrier issues also concern me about self adhereing flashing. Another option would be to use some traditional aluminum drip edge and install it under the bottom piece of siding. But I’m not sure if this would be effective against insects. Does anyone have expe ri en ce with this and/or suggestions?
Thanks
Replies
Your issue of water finding it's way through the slab/bottom plate joint combined with the issue of your siding be too close to the ground in a wet environment leads me to one suggestion. Remove the bottom course (or 2 depending on it's exposure)of siding, then seal the joint with some combination of caulk, spray foam, peel and stick flashing. Then add a water table trim around the house again covering that joint by a good inch. Use a rot proof material like PVC and you can get closer to the ground. Also make sure to use proper drip cap above the water table.