Using thermally broken 2×6 studs
Gene_Davis
| Posted in Energy, Heating & Insulation on
Here is what they are. Imagine a 2×4, at standard 1.5 x 5.5 section, having a 1.5 x 1.5 section of rigid foam glued to it’s edge, and then on that, a layer of 1/2″ OSB.
The OSB layer goes to the inside.
Ever used them?
Replies
Nope.
No- sounds goofy, but maybe I don't understand without a picture.
The really strange pat is the 2x4 that is 5.5"
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My typo. Imagine a 2x4 faced with two layers as I described.
Photos to follow.
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Not a photo, but a quick Sketchup.
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"A stripe is just as real as a dadgummed flower."
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Loks neat. Love to know how they'd hold up in the lumber pile, stand up tp weather, and how inspections viewed them?http://www.tvwsolar.com
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We'll report back from the real world in a week or so, but as for inspections, you've heard me say before that they don't happen 'round here.
Guy I know is building, and I'll go an help with the framing. His supplier came across a few bunks of these and offered them at perhaps a deal. I'll see if I can determine the manufacturing source.
Our local AHJ wants all houses framed with 2x6 exterior walls, but that is really just an insulation thing. I'm sure a criscross as per M. Hussein S. would make anyone who cares, happy. I'm sure these will, too.
As we all know, walls framed in 2x4s are holding up some pretty substantial roof structures, all over the place.
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"A stripe is just as real as a dadgummed flower."
Gene Davis 1920-1985
You tryin to say youre buildin heavy houses with them too?
Got a brand name for those, or a link?
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"walls framed in 2x4s are holding up some pretty substantial roof structures, all over the place."
Right, but these are really 2"x6"s with no substantial bearing on their outer 2". How do you see them supporting roof rafters, rim joists or beams that usually rely on that portion of the stud? Not saying they won't work, just trying to understand how.
I am thinking the solid 2x4 section goes to the outside.
Don't think of these as 2x6s. Think of them as 2x4 studs padded to the inside with a rigid foam 2x2, then skinned with an 1-1/2" strip of 1/2" OSB. Just like my doodle.
The foam is providing the thermal break, keeping the studs from transmitting heat through the walls.
Headers are all two ply packed to the outside, thus bearing fully on walls.
Where is the structural problem? Are not substantial houses built in large parts of the country, framed with 2x4 exterior walls? If M. Hussein Smith frames a house with his "mooney wall" setup, isn't that essentially a 2x4 frame?
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"A stripe is just as real as a dadgummed flower."
Gene Davis 1920-1985
I don't know why I assumed the foam went to the outside. It makes perfect sense the way you describe it.
One thought: Our code allows 2"x6" framing to go to 24"oc. , where the 2"x4"s have to be at 16". That goes some way to eliminating the advantage of the foam studs. Although I guess if the top and bottom plates were also foam composites you are way ahead.
How strong is the bond between the materials? Do you think you could hang cabinets off a wall framed with them, or would you need to install blocking?
If you have a pile of them sitting around, I don't see any problem with using them in a non-critical application and see if you like them.If this is purely a theoretical question, I would want the OSB flange to be wider to make splicing rock together easier (perhaps wider on one side only so that when doubling up a stud is necessary, it isn't necessary to trim the OSB). And I would like to see a 1" hole in the foam every 12" or so for wire and water supply lines unless that breaks some sort of code issue I don't know about.In general, I like the idea, although there are already a number of fairly simple and common DIY ways of breaking the thermal barrier if you want to go to that trouble.
I don't think the brick ties nailed into the foam (osb + foam) are going to help much, then again, nor would the drywall screws. Only about 5 % of the studs won't twist, wouldn't that just peal off the foam? Maybe there's a reason the yard is discounting them?
Edited 7/27/2009 8:04 am ET by wane
Hey, he told you the wood is to the outside!>G<
Being a fellow Canadian this looks like a product made for us. I assume that the foam goes to the outside of the wall. That will provide the thermal break that the 1" of stryofoam does when applied over the OSB sheathing. Then there would be on difference with drywall, etc.
Let us know how it worked out.
No. But I can just hear the complaints. If you had a twisted stud, there'd be no way to tweak it into compliance. There are probably many situations in framing a house where that foam would getcha. The OSB would be OK for fastening rock to, but would be marginal for attaching base. If a plumber had to cross studs (as typically occurs when venting the kitchen sink), nothing would be left of the 2x4.
Now don't get me wrong, I'm all for the concept of reducing thermal bridging--I'm just skeptical of this approach.
I see electricians liking them; no more drilling, just jam the wires through the foam. :)
Is this a creation of yours or something you've seen already in production?
My 2 cents:
Seems 2x4 is a bit small. Also almost as easy to sheath a 2x6 wall w/ 1/2" polyiso, use let-in diagonal bracing for the same affect and far superior thermal properties ... notwithstanding your friend getting a 'deal'. 2x4 seems very wimpy.
Seems 2x4 is a bit small.>>>>>>>>>>>>>>>>
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vs. a 2x6, that is. 2x6 is so common anymore, not sure why anyone would opt for a 2x4 (not that there isn't a time and place for it).
Still rather un-common around here. Not un-heard of, just not frequently done. 2x4 has more than enough strength in compression to hold up a few floors and a roof. Also, no inspector will pass it with all of the mechanicals running through the foam. I'm pretty sure IRC states that they have to run through the middle of the stud to avoid puncture. It's either plate off every stud at every location, or drill every one.
2x6 @ 24oc vs. 2x4 @16oc is nearly a wash (cost/material wise) and fewer pieces to handle/nail. It is superior energy wise. I'm surprised it's not used more up there (2x6). I've been few places where they do otherwise. 2x4 still used for interior walls, of course.
There are other factoids besides the cost of the framing lumber... door and window jamb extensions can be a major up charge.http://www.tvwsolar.com
We'll have a kid
Or maybe we'll rent one
He's got to be straight
We don't want a bent one
He'll drink his baby brew
From a big brass cup
Someday he may be president
If things loosen up
Both should be available for 6" wall framing. However, I did by a jamb extension for a door I bought off the shelf. It was like $23 and it took me like 15 minutes to install (my first time doing it).
I'm surprised as well. I've realized the benefits of for years now. I've talked to lots of framers about it and have heard every excuse. The lumber is harder to work with, the sheathing sags between studs making the siding look wavy, 24" is too much for 1/2" drywall. I honestly don't get it.
Do you not agree that 24" is a lot for 1/2" on walls?I like 2x6 @ 24", but I think you need to take in to account the GWB, sheathing, and floor space it eats up.
Jon Blakemore RappahannockINC.com Fredericksburg, VA
1/2"GWB is made for 24" oc I believe ... of course it is. Flimsy? Maybe for rental applications, but not your own house. You could go to 5/8 on ext walls if you need to; just order extra w/ the ceiling rock.
All the excuses people come up w/ for staying w/ 2x4 or going 16 oc, IMO is a bit much. While there is certainly a place for 2x4, 2x6 is generally far superior. There is always a time and place for anything.
Takes up more floor space? Give me a break. With all the oversized wasted floor space people tend to design into their mammoth houses, how can you grouss about a small percentage loss? Rationalizing, IMO.
Personally, I do think 24" is too far, but I believe that regular 1/2" gwb is rated for 24". And if you do push sheathing and sheet rock up to 5/8" you are no longer "breaking even" in material costs. I'm not too concerned with the amount of square footage it eats up. Thats minimal, and most houses are more than large enough for a typical family.
Or stagger 2x4 on a 2x6 plate24 on center
Now THAT is thermally broken! Nice option IMO. The thermally broken stud as a product seems like generally a lot of effort/expense for the gain.
Hmmm.... Interresting point.It seems that if you rotated every other one of Gene's fancy 2 X 6 stud sandwiches around, you'd get very close to the same effect that a stagger-stud 2 X 4 wall gives you, without the hassle of either framing the wall twice (or nailing, flipping and re-nailing), or toe-nailing the second course of studs in place.Of course, if you were tacking conventional FG batts up, you'd be stuck stapling to the stud face, which tends to be more insulative anyways (even if the drywall crew hates it...).-t
I don't see why you wouldn't just do a 2x4 with a continuous sheathing of rigid on the inside for the same effect, but with increased airtightness to boot.-------------------------------------
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What is today's cost of a 2x6x9P (i.e., 104 5/8" precision-cut)?
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"A stripe is just as real as a dadgummed flower."
Gene Davis 1920-1985
Sorry - I wasn't arguing it's a best practice, I was just pointing out that it seemed interesting that two different approaches to energy efficient wall construction were nearing convergence.-t
Have not read the thread, but after a few days cannot resist:
I got plenty broken 2x6 studs, how many you need <G>