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Can I spray foam insulate from the outside?
Kurt Klischuk
Published: June 6, 2019, 8:56 a.m.Last updated: July 24, 2019, 10:56 p.m.
I bought an old timer home on Gibsons, BC and the siding needs replacing. I want to use the opportunity to seal up and insulate the wall cavity once exposed. I expect to see insufficient or no insulation. After applying spray foam what is best to apply (tyvek vs. something other) before installing the new board and batton siding?
Thank you, Kurt
Hi Kurt,
Are you not expecting to see some sort of sheathing behind the siding? In order to spray foam properly from the outside you would need to see bare studs, and spray foam in the stud cavities. So that would leave you without sheathing, so you would need to re-install sheathing or at least wind bracing if we are understanding you correctly. To re-install siding afterwards you would be wise to create an air space so the exterior of the wall can dry. Here is our how to install siding properly video, and another on how to install a weather barrier. And read here for more information about choosing breathable weather barriers.
Let us know more details about our wall assembly and what is behind the siding if you'd like, and we may be able to be more helpful.