I need assistance with window/door install with 4″ foam

kenorakq | Posted in Green Building Techniques on March 28, 2015 01:37am

I am looking for some direction on installing windows and doors. I have 4″ exterior EPS on a 2×6 walls

The current plan is to build 5/8″ plywood boxes (I believe they are called Dewey boxes) to get the nail fin of the window to the same plane as the furring strips that the foam and the siding will be attached to.
I am sure its been covered but searching Dewey box got me 0 results so I wonder if someone could point me in the right direction?

Thanks
Tim (Kenora ON Canada zone 7)

Answer

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Replies

DIYJester | Mar 29, 2015 09:20am | #1
Tim,
Try searching "Dudley" boxes and "innie and outie windows". There are numerous articles and cut sections on how to build these.

I'm not going to attempt to replicate the details or know how that these articles have as I have not physically built a set of Dudley boxes; I've only been doing the research like you.

Don't forget to plan for furring strips. There are lots of articles on these too.
LucyF | Mar 29, 2015 11:55am | #2
These are the most relevant articles I think you are looking for: https://www.greenbuildingadvisor.com/blogs/dept/guest-blogs/window-installation-tips-deep-energy-retrofit

https://www.greenbuildingadvisor.com/blogs/dept/musings/innie-windows-or-outie-windows
kenorakq | Mar 29, 2015 12:26pm | #3
DEWEY...... DUDLEY.......DOOOH :)

Thanks
user-1072251 | Mar 29, 2015 01:58pm | #4
When we install windows with nail fins on a wall with polyiso, we install 6" wide strips of 5/8" Advantech in place of the strapping, using 6" screws ,made by GRK or equal. Then fasten your windows directly to the Advantech. Alternatively, or additionally you can use "masonry clips"; steel straps which are screwed into the window and screwed into the framing of your stud wall.
kenorakq | Mar 29, 2015 05:25pm | #5
Thanks Bob...I'm Goggling Avantech to learn more
kenorakq | Mar 29, 2015 05:31pm | #6
Just found it....it looks like a competitor to plywood and OSB...I was planning on using 3/4" plywood strapping, including 6 inch strips around the windows.

Has your experience with Advantech proved it to be worth the additional $$$... do you do all the strapping with Advantech or just around the windows....thanks in advance.
Irishjake | Apr 08, 2015 09:58am | #7
Tim,

Advantech is far superior to plywood or OSB when the issue of water comes into play....
dburgoyne | Apr 08, 2015 11:15am | #8
I handled this a little differently by framing rough window openings 3 inches larger and framing in 2x trimmers cut from 2x12's, flush with the foam. I screwed them into the jambs, header and sill, as well as each other at the corners. This way, the windows could be attached to solid 2x lumber. I used 1x4s for strapping.