Framoing Question

[Jim Robinson]

I'm building a house for my wife and I, and doing a lot of the work myself. I am using an insulated header to prevent thermal bridging. Do any of you know the fastening schedule for the headers? I found 602.3(1) items 10 and 27 which sort of cover it. Neither one is calling for an extraordinary amount of fastening, which makes sense. It's not under much pressure side to side. I used 3 5" screws every 16" to fasten it together. I'm comfortable with it, but not sure what the code says about it.

[Jerry Peck]

You are doing something not covered by the codes, so you really need an engineer.

Double 2x headers are there to carry the load from above, and that is not a double 2x header. That is two single 1x headers with no structural connection between them.

[BARRY ADAIR]

not so sure eng is necessary
typical 2x header w/foam @ interior is what is commonly done, i ? interior based on what i've seen
https://www.youtube.com/watch?v=fa-7L4locLk
i'd think the sealed foam at the outside would be a better choice to avoid any potential for air/vapor transmission condensation within the header
i'm a bser but not a building science (bs) engr/architect so consult one in your area that knows what works best for your climate

[Jerry Peck]

not so sure eng is necessary
typical 2x header w/foam @ interior is what is commonly done,

The problem is that he didn't make it that way, the foam is neither on the inside or the outside, it is sandwiched between the two 2x, thus making them structurally independent from each other.

If the two 2x were next to each other and structurally attached to each other, that would have been different, then add the foam anywhere there would otherwise be "empty space", even center the two 2x header and put foam outside and inside ... I am not addressing "where the foam should be" (inside or outside), only "where the foam should not be" (between the two 2x structurally separating them from each).

[Jack Feldmann]

I agree with Jerry. This isn't really a proper header, since the foam can compress between the two 2x's. Kind of defeats the purpose of doubling them.

[Jim Robinson]

Interesting takes on it. I will have to see what our AHJ says about it. The load path is vertical, and they are fastened together. For many years, we built headers by ripping a 2.5" block to put in between and just left the empty space. Still how it's done most places. I can't see this being much different. I can't see how one side would get weight on it without the other side. But codes are codes.

I could definitely put the foam on the inside pretty easily, and push the doubled up header to the outside of the wall. We have a double stud wall, so the foam on the inside is not a factor for trim or sheet rock. I can also through bolt, which would be easier. I didn't really see this as an issue, but perhaps it is.

[Jerry Peck]

The load path is vertical, and they are fastened together. For many years, we built headers by ripping a 2.5" block to put in between and just left the empty space. Still how it's done most places. I can't see this being much different.

What were the blocks made of? Wood.

You would never have done that using small cardboard boxes, would you? No, because cardboard boxes had no strength.

Neither does the foam.

The dead load is vertical, correct, but there is also live load too, which is typically horizontal ... but let's just think of the dead load as that is greater.

Why not use one 2x for the header?

Because it's not strong enough and could twist and\or bow.

Adding blocks between two 2x headers makes them as one and keeps each separate 2x from twisting.

Adding foam between them does almost nothing.

Put the foam inside or outside ... or get an engineer to sign off on it.

[Jim Robinson]

My SE got back to me tonight and said to put them back to back on the inside or outside, or to box it with a cap piece and bottom piece. R value will be a little better if I put it together and put it to the outside. Not a big deal to switch it around. With the screwed connections between the 2x and the sheathing on the outside, I'm still pretty skeptical that it isn't strong enough this way. But not skeptical enough to spend any more time on it. I always pictured the blocks as providing the spacing for the 2x so that the exterior door and interior trim works properly. Maybe the block connections are stronger than they seem.