Zone 5 - Chicago area. planning to use 1.5" exterior rigid with 0.75" thick 1x4 kiln dried.
I am curious what methods you guys use to frame out around windows. I have heard several methods:

1) put the window in normally - hanging out past the sheathing - and use brick ties to hold it in/down. I don't like this method b/c it seems like a poor attachment and to make changes to a window the drywall inside will need to be ripped out.

2) put the window in normally - hanging out past the sheathing - with foam run up to the edges. Use 1x6 strips of Advantech to "cap" on top of the foam to "frame" the window to nail into. The frame "cap" will sit on top of foam. I kinda don't like this because I feel the window could move or the foam might compress

3) Box out the rough opening making the r/o 1.5" larger in both directions and use the "Advantech" to make a "sleeve" to slide the window into. This sounds better of the three so far. but I wonder if the sleeve's 0.75" nailing surface is enough?

I watched every youtube video I can find on this. Any insights? I will need to build the "cap" over the foam to frame/furr the window out so siding can be nailed up to the window, I suppose I will use Advantech for this. Do I need to make the sleeve as well? Does it have to be Advantech?

what are you using for siding/cladding?

Either LP Smartside lap siding or JamesHardie Fiber Cement lap siding

Thinking about this, I should be able to just use the same 1x4 kiln dried furring around the window that I use for the siding, yes? And use the same flat head fasteners ( I will use 4-0" HeadLOK FMHLGM005-250 ) that I use to attach the furring strips on top which will be pretty secure to nail the windows into yes? In other words, option #2 above...?

the furring around the windows should be wide enough for the window flange (of any) and for fastening any trim around the window. 1x KD should work fine.

ok I will plan to use 1x4 kiln dried furring and look into that Advantech to see if HD sells that (where I am getting my lumber).

Posted By Surfsup on 01 Jan 2014 03:36 PM
ok I will plan to use 1x4 kiln dried furring and look into that Advantech to see if HD sells that (where I am getting my lumber).

The air gap only needs to be 1/2". Use strips of 1/2" ply or even osb. You can rip the pieces for the corners and around the windows wider to allow for nailing both the trim and the siding. The ripped sheet goods won't split like 1x tends to.

Good point, FBBP. I was concerned about exterior corners. That will make it easier for sure, though lots of extra cutting. that table saw is going to get a workout...

How confident are you guys in using furring or OSB/Advantech on TOP of the foam around windows? I am getting some mixed signals here from others on a different forum. Saying I should use a frame with the wood tied to the underlying studs for rigidity...

vs the whole house envelope making a rigid assembly using a 2x4 around the window won't hurt thermal performance THAT much...

I don't understand the question - are you worried that the foam will shrink? What is the argument not to do this? Most, if not all windows with flanges have non-rigid flanges and/or a non-rigid attachment from the flange to the window, so even when attaching flanged windows to sheathing fastened to studs, it's still a non-rigid attachment.

IMO the best way to attach windows is to use "masonry clips" which are metal straps fastened to the side of the window and screwed into the studs. That said, flanges are much easier all around and we've seen -0- issues with installing them this way.

the masonry clips I thought about but the problem with drywall returns is if anything happens I'd have to tear up the drywall. I suppose you are correct the flanges are not rigid either...ok. I feel comfortable with putting the nailing "frame" on top of the foam...

With the window over the furring strips, and the furring strip over the Tyvek, how do I seal at the window nailing flange the proper way? Should I just Tyvek wrap the side furring strip again and tape it to the face of the tyvek down the side?

flash the advantech or whatever you are using for furring to the foam, or to the underlying sheathing, and from there over the window cap.
Tvek must lap onto the flashing so water draining down it does not go into the window. The tyvek also goes under the side strapping. We tape the window flange directly to the advantech with SIGA; many of the tapes will not stick to unpainted wood or plywood.

flash the advantech or whatever you are using for furring to the foam, or to the underlying sheathing, and from there over the window cap

I was planning to cut horizontally a slot in the tyvek, take another tyvek strip and slide it up and in over the window and tape that. The new tyvek strip would go over the top piece of furring strip and be taped over the top of the window's top nailing strip.

I will check into SIGA.