Thermally Broken Studs

UpNorth

Ever used them? A client for which I did plans got a deal on enough to frame his new house.

Thought I would post a couple pics, now that the place is mostly framed out.

Studs and plates are all 2x4s, to which the manufacturer has laminated a 1.5x1.5 layer of rigid iso foam, then an inner nailing surface of 1/2" OSB. Maker is Nordic Engineered Wood Products, of someplace in northern Quebec.

Insulation in walls will be 3" nominal thickness spray iso foam, the fillets of which will pretty much ensure no delamination occurs between the rigid foam thermal break and the studs. Or so the owner hopes.
My apologies to the dialup folks.

I helped frame for a couple days, and in my experience, the loss from delams was pretty minimal. The way that Nordic makes these, the lams are resawn once the glueup is done, with the inside parts measuring about 1-3/8", so that any ganged members are tight, wood to wood. A close look at the pics will show the telltale sawkerf mark about 1/4" onto the 2x4.

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JumboJack

Why not just use 2x6's?

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in texas with framing and cornish people will do it for 3.00 a foot. What do yall think about that? Just laber

concretemasonry

2x6's would obviously be better structurally, but there is still a "thermal short circuit" through the wood.

This thermal short circuit is the reason why R19 insulation in a 6" wall actually gives an R10 to R15 wall at best (in a short term lab test). The only thing worse would be a steel stud.

If you are just concerned with material costs, and tradition and you can sell the owner on it, it may be within "code" (which is the worst way you can build and still be legal) and not the best way.

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Dick

Engineer, designer and consultant recently active domestically and internationally on construction and design in about 35 countries.

mics_54

That's one way...another way is to use 2x6 top and bottom plates( or wider) but use 2x4 studs staggared on 1' centers... the outside course for the exterior surface and the inside course for the drywall which eliminates thermal bridging.

mics_54

I'd say overall the design looks terribly costly in labor. I've seen a few energy efficient homes being built here in alaska with 2x4 walls for structural frame covered on the exterior with 4 inches of ridgid foam and an outer layer of bitumin.

KentWhitten

There are dozens of ways to break the thermal bridge. Half inch rigid foam inside or out would do this. A ceramic coating does too (it's applied like paint)

This manufactured stud to me seems unnecessary.

2x4's look like nice material.

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canadianwood

Hmmm, that is interesting but almost seems "gimmicky" to me, XPS on the outside is probably the easiest way to get that thermal break (as framerman stated).

I walked through a "net-zero" house built here in Edmonton that had an interesting design for its exterior walls (its a duplex whose net energy use over the course of a full year is zero, keep in mind that we regularly get down to -30 Celcius in the winter, so its quite impressive IMHO).


Walls were R56! Exterior wall was 2x4, 16" space, inner wall was 2x4 @ 24"oc. This design also gives you an almost 100% thermal break.

Link: http://www.riverdalenetzero.ca

BirmanBuilders

don't think the trim will hold on too well to 1/2 osb! what about drywall? Do they have to use longer screws to hit into the stud?

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UpNorth

Here is a shot of the project thus far, and for comparison, a render of the design as done using Chief Architect software. Roof trusses go on next week. Except for me helping out for a little bit when framing walls off the first deck, the entire thing, dig, footings, foundation, framing, etc., has been done by owner/builder and his one helper.

The photo is a pretty good approximation of the view seen from the second story windows looking W. That is the upper L in the photo and render of the house, the windows looing out over the screened porch.

The sun in May, June, and July, sets near Indian Pass, which is the deep notch in the photo of the range.

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Tom Struble

looks awesome

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mics_54

yea...nice job!

Framer53

How much time have they into the project?
Looks like a nice site!

WNYcarpenter

I was wondering the same thing.

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Tom Struble

interesting i thought the foam would be on the outside

UpNorth

I just ran some numbers on how many manhours have gone into the project from groundbreaking to where you see it in these pics.

I get about 950 total, half of which the owner/builder got for free, since it is his own labor and he is sort of retired, and the other half is paid for (475 manhours) to his able assistant, a very capable 66-year old.

Let's presume his fully-burdened cost for those 475 hours of hired labor is $30 per hour. I get a total cost of $14,250, and I'll bet that is conservative.

That includes all excavation, underground drainage, underground to existing septic system, footings, foundation (all Amvic ICF), and the frame carpentry you see. The owner has for a long time operated a cabinet and tile business, and is a very talented mason and carpenter. His helper is a retired stonemason.

The owner has a John Deere loader/excavator/backhoe with all kinds of attachments for hoisting, etc.

Nothing at all will be subcontracted in this project. Plumbing, HVAC, and electric work will all be done by the owner/builder.

UpNorth

Trusses are up on garage and connector.

The garage has a square footprint, about 25x25, a hipped duncecap roof at 6:12, and with no internal supports wanted, trussing was the solution.

The overhangs are such that the truss hips have 2x8 top chords. When the roof goes on the house, with its 46" overhangs, we will see the hip trusses with their 2x12 top chords. The truss supplier used machine stressed lumber with a higher allowable stress than #1 structural, for these.

Perfection in planing was gotten everywhere. Trusses were ordered with 1" extra tail extensions, so as to allow for tail cutting to a stringline, but the fab-up was so good that no cutting will be done. Tails are in line, as-is.

No blocking or capping is on yet. They just got slapped up quickly and braced across the commons, as can be seen.

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UpNorth

A photo, and a rendering from the Chief file that shows where the project is headed.

Trees are northern white birch, and leaves will be falling soon. The summer birds, the robins, virios, thrushes, swallows, and the others, have all left, and things are pretty quiet. All we have now for bird noise are crows, jays, chickadees, turkeys, grouse, and some loons. The loons will head out in a few more weeks.

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oldfrt

I don't get it!!!!!

All that expense for thermally broken studs and to save what?

You're going to lose a ton of heat through all that glass.
Is that issue addressed in this design?

Are they counting on passive solar gain?

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UpNorth

Windows are by Thermotech.

You are invited to study their specs by going here.

Triple pane, special inert gases, warm edge spacers, high-performance coatings. Pretty special, and verrrrrryyyyy pricey.