Air sealing at the mudsill
After watching “Passive House Video — Episode 2″ I’ve been thinking about doing more to stop infiltration at the mudsill in our new house build. In the video there are several layers between the foundation and the actual mudsill including a copper sheet, a sheet of plastic, a gasket, and some sealant goop. In one place on GBA someone said that the common polyethylene sealing strip that comes in rolls is fine if you caulk the seam in the basement. But I like some of the ideas in this video. I’d prefer to keep poly sealing strip but add a bead of sealant between it and the foundation just to cover some of the worst irregularities in the concrete surface. On top of the sealing strip I’d add a strip of tyvek overhanging a few inches on both sides of the foundation. Inside the basement the tyvek would be sealed/taped to the 1” layer of XPS lining the basement wall. Outside the tyvek would be sealed/taped to the exterior sheathing so that the next layer of tyvek would shingle-layer over it. I’ve attached a rough sketch. I would think adding the bead of sealant and the layer of tyvek is a vast improvement over just the sealing strip. Any thoughts? Pros and cons? Thanks for any insights.
House data — double stud wall, no exterior insulation, plywood sheathing, climate zone 5 (Lancaster Co, PA)
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