Rate my wall
Greetings Everyone,
I purchased the GBA subscription with the hopes of finding details on what in had in mind for a owner/builder home construction. The intent is to do some of the construction myself. The focus of the construction is economical and easy of assembly with slight upgrades in materials such as exterior foam and advanced framing techniques. The site is in Ellabell GA which is on the border of 2a/3a. I looked through the details on the GBA and other sites and didn’t find what I was looking for. I did find this website, draw.io, which is extremely easy to use and was able to generate this detail to work out my ideas. Please scrutinize this detail and give me all of your opinions on it.
Thanks, Brad
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Replies
Hey Brad,
Looks good to me!
Couple of thoughts:
1" Foil -faced Polyiso is readily available and would be a good choice for the exterior foam.
The Building Science Corp reccomends using a "bumpy" housewrap like hydrogap, or tyvek stucco for your mechanically fastened WRB. This creates a bit of drying space between sheathing and foam boards with minimal thermal penalty.
Be sure to tape your OSB seams for improved airtightness. 3m all weather tape is one of the few affordable tapes that work well on OSB. Zip system is a great option too and you can eliminate the WRB.
Rick,
Thanks for the response. In the detail I have the house wrap over the foam. What benefit does a foil face foam have over a non-faced foam in this application? Should the house wrap be behind the foam? With wrap behind the foam I understand the need for a drain type wrap and also a benefit of a radiant barrier on the foil face foam.
In this detail I moved the housewrap to under the foam and over the ICF. I don't think think I like this set up as I understand the foil as water and vapor non-permeable.
Brad,
Where the house-wrap is situated influences how openings are flashed, as any flashing should go back to, and be lapped by the WRB.
I don't think there is any point in using a drain type WRB if you are including a cavity.
I'd suggest interrupting the strapping and cladding at the top of the foundation and dividing the levels with a drip flashing, as the chances of the entire house framing being exactly coplanar with the foundation insulation below are pretty slim.
Brad,
Now you have moved the wall in to bear more directly on the concrete foundation, you may want to reduce the size of the sill-plate..
Brad, do you have termites in your area? If so, then detail to handle them would be a good addition.
Bill