How do you frame around windows when using staggered stud wall framing techniques? By staggered stud, I mean 2×6 plates and 2×4 studs, offset from each other, eliminating the thermal bridge. The rough window sill will be 2×6 and the jack studs (in BC we call the studs that support the sill, under the window jacks) will be 2×4. How do you frame the cripples (the vertical member supporting the lintel/header, in many places these are called trimmers)? Because they support wall finishes on both sides, should these be 2×6 as well?
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
Learn more about the benefits and compliance details for the DOE's new water heater energy-efficiency standards.
Featured Video
Builder’s Advocate: An Interview With ViewrailHighlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Replies
2"x4" studs staggered in the field, and 2"x6" at the ends and around all doors and windows. Including headers, cripples, and the studs at the ends of the headers. I've had to do this for townhouses and duplexes.
Frankly, I'd reconsider this framing method.
I've done it and after living in the house and the results....
If you can afford couple of more inches inside, go with 2X6 exterior framing 24" oc and 2X3 strapping applied horizontally on top of a vapor barrier.
Air infiltration is the key.
I grew up and lived in Saskatchewan. The last house I built there used about 50 bucks a month in heating costs including HW. (all gas).
Details are everything. You must have a heat recovering air exchange system. I built my own from plans I got from the Sask Research Council. But commercial varieties work well and are a small percent of the cost of a house.
You allude to unsatisfactory results with staggered stud framing. Any specifics?
I've seen 2x6 walls with 2" extruded polystyrene or other rigid insulation on the exterior of the sheathing. It can act as an air barrier as well.
When you strap horizontally do you insulate the space between the vb and the drywall/interior finish?
Man,The house I built with staggered studs just didn't perform that well. Weaving the 'glass was labour intensive, and maybe could have done better.I also didn't know what I know now about properly sealing up a house, so that was a factor as well.The beauty of hor. strapping (which is insulated as well) is that the electrical boxes and the drain and water lines run in the 2X3 and rarely, if ever, have to penetrate the vapour barrier. This is of key importance.Alan
If you're going this route, what are you going to insulate with?
If it's open cell spray foam, you'll find that there's a fair bit of overspray/trimming waste and potential for minor bulging of your drywall between studs even if the foam guys do the best job they can with their trimming. I went this route with my place and that's what I experienced. Fortunately I don't care about having dead flat drywall so it doesn't bother me, but others would be unsatisfied with the result. The 24" centre spacing for support of the drywall is otherwise no big problem, as the drywall has continuous contact with the foam and does not feel flimsy in the slightest.
If you're going to do dense-packed cellulose, look up the Mooney Wall here. 2x2 furring on the inside of a regular 2x4 wall. Better than staggered studs by far- for the same amount of wood, you can get a similar reduction in thermal bridging with the advantage of 16" centres for support of your drywall. But I would imagine that Mooney construction would be a b*tch to spray foam the bays completely full. Partially filled bays would only pass local code here if you went with closed-cell foam such that no VB was required.
If you're planning to use rigid foam, it'll be a tough job to install the foam if you do it after the walls have been sheathed and erected.
Search Breaktime for "Mooney Wall" -- a more refined approach to thermal bridging.
-- J.S.
Gene Leger is the guy to ask, but he's long gone from BT.
He built this way in the 70s and had good results.
I have a book somewhere with some info about it. He was spending close to zero on heating in a couple of experimental houses he built. Insulated with cellulose.
You might try google and come up with something. Leger House maybe, or Gene Leger.
Joe H