So this is just a point of interest and I know I’ll tap the well on this one.
If 2×10 solid sawn are used interchagable for floor joist and header material why can’t you use TJI’s for headers?
Would seem to cancel out the effect of shrinkage and the web void would make a nice cavity for foam board insulation.
I have no plans to do this as I rarely do any framing but just always wondered why.
Mike
” I reject your reality and substitute my own”
Adam Savage—Mythbusters
Replies
Intriguing idea.... I think though that you would need web stiffeners, which, by the time you went through all that, the rigid foam insulation would be significantly reduced to where it just wasn't worth it...
Edited 2/6/2006 7:11 am ET by Matt
Theoretically, it's possible. But realistically I doubt it's a good idea.
I-joists are NOT interchangeable with 2X lumber. Each one has different strengths and weaknesses.
I-joists used as headers might work, but would require exaluation for each situation. They may need web stiffeners or other modifications.
To the best of my knowledge, none of the I-joist manufacturers recommends them for headers.
If you like insulated headers, check out these:
http://www.swi-joist.com/p_04.htm
I see in the Superior site the end view looks like it would if you ganged two TJI together--So this only strengthens my original idea that the system is generally better than 2x solid material.Seems like the engineers have pondered the idea before and I just am on the slow boat of ideas.Again this is in theory only and just a point to ponder--I do remember an article a while back on insulated headers--Box type and such--What will they think of next--Insulated baseboard--oh wait they already have--foam--what a wonderous material.Seems like they could wrap SIPs material in 2x for nailing and make header material out of it---Seems to me that that system has no headers and relies on the stress skin to transmit the load around the opening.Thanks Boss--just bouncing one of ya.Mike" I reject your reality and substitute my own"
Adam Savage---Mythbusters
I get scrap 16" LVL 7-8' odd lengths for $5 at my lumber supplier. I then use a 2x6 flatwise for the bottom of the header, then rip the LVL to height to fit under the top plate (or merely cap it with another 2x6 for tall walls). The LVL is flushed up with the ourside framing plane, leaving a 3-3/4" deep cavity for insulation (obviously this is for 2x6 exterior walls).
Forrest
Forrest, I have seen this done around these parts and the debate continues--void to the inside and insulate or void to the outside and foam board to keep the header on the warm side of the insulation.Most void to the inside--and I see the arguements both ways--I think most leave the void to the inside because that means one more step in the framing process if they had to stop and insulate the header before sheathing. I have no intention of using TJI for headers--just pondered the concept and knew if I asked others would explain the rational.Till next time.Mike" I reject your reality and substitute my own"
Adam Savage---Mythbusters
Mike,
You can't use a regular TJI for a header. In other words if you had an extra 3-1/2" x 11-7/8" TJI left over, don't use it for a header because it will fail unless you build it up or something. I know because this builder I was framing for about 10 years ago told me to use one because he didn't't want to get another 2x header. Within a couple days it sagged almost 3/4".
There is a website that does make TJI/I-joist headers because it was posted here a few years ago and maybe it's the one Boss posted.
Joe Carola
Edited 2/7/2006 9:19 am ET by Framer
I don't know about the prior web site but I did visit the one
Boss gave me and it looks like what I envisioned--The whole TJI issue was just inquiring minds----Although when I do get to adding the addition on to the house it will be nice to know more about the things I don't deal with every day.Thanks to the whole gang--the things ya learn--"if ya can't listen to a guy named Framer who can ya?"Mike" I reject your reality and substitute my own"
Adam Savage---Mythbusters