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XPS on exterior walls

Amac78's picture

I'm considering buying a house built with 2x4  walls and fiberglass batts.  I want to install XPS on the exterior walls to add "R" value to the walls and reduce thermal bridging.  My question is - is it necessary to remove and reset all te windows and doors to accomodate the additional wall thickness or is there a way to NOT remove the windows and flash them so they don't leak?  I need help on this one.  Is there a construction detail I could use?

Are you familiar with the (post #209283, reply #1 of 2)

Are you familiar with the term "jamb extensions"?  Usually referes to interior trim, but the same concept could be used on the exterior of a building. 

There's no inherant advantage to the windows being in the exterior plane of a wall - in fact, that's one of the advantages touted by designers of superinsulated shells with abnormally thick walls  (sometimes 16" thick) -  the ability to set the windows further in towards the interior plane of the wall creating a sort of "window well" which protects the window and sealing materials from at least some direct weather.  There's some logic to it, for sure.

Check out the Passive House, or superinulated shell websites for detailing.  I'm sure you'll be able to find something to get you started, then maybe modify a little for your specific design needs.

Could easilly be something at Building Science Corporation's website too, but it's not something I can say for sure. 

Thanks (post #209283, reply #2 of 2)

I'll check Green Building Science website for a detail.  Thanks for the quick response.