Why Isn't There Any T1-11?


davidinvest
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Go to solution Solved by dshall,

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T1-11 has too many issues with achieving brace wall shear panels.  It has become associated with low end builders.

I don't have any problems using t-111 over shear walls, you will of course need to shear the whole wall or furr it out to match. Not low end around here.

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I agree that this should be much easier to accomplish than it is now. It can be done using the methods stated above, but there really should be something a bit easier to work with.

I had a project a few months ago that was an addition on to a house that has T-1-11 siding. I thought the same as others that with only 5/16" of remaining panel that it would not have enough shear rating to work. I was surprised to find that the actual thickness of the remaining panel was not the issue. The issue is the rating stamped on the back of the panel by the manufacturer. It turned out in my case that the siding's shear rating was fine.

There is another issue with using a product that is both the sheathing and the finish siding and that is the application of the rain guard type of barrier or the lathing. Nothing so far seems to make a whole lot of sense to me about how to go about this type of situation.

So, if it is not so much the shear issue that has many builders using far less T-1-11 today than they used to, then I would think that it would probably have more to do with market preferences and the association with low cost housing that is being avoided. Two cents.

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Using it over shear walls is fine.  A lot of builder want to use it as both the sheathing and siding.  The grooves make it too thin to qualify for prescriptive panels.  You can get thicker t1-11 but it may be cheaper to use sheathing and real siding.

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What I found is that in order to qualify for use in the prescriptive method it is the manufactures thickness rating, not the actual thickness of the panel that counts.  I agree that it does not make a lot of sense, but that is how I understand it to be viewed by building officials.  Kind of goes against everything I was taught in engineering classes, but it appears they are leaving it up to the thickness rating stamped on the back of the sheet by the manufacturer.

 

BTW, I was using the continuously sheathed prescriptive method and it passed just fine.

 

Another thing that I found to be a bit irritating is that it is very difficult to find the thickness rating unless you actually look at the back of the sheet.  That information has to be available somewhere, but trying to determine who the manufacturer is and then find their rating is a royal pain.  There probably is some consistency between manufacturers, but I did not get much help with that from any of the suppliers.

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IRC calls for 3/8 continuous. Rod is right the mfg rates the panel in their data sheets for shear and buckling is what some have if the stud span gets too far. I think some just want to sell more wood so say 3/8 fails which I doubt. I've seen ICC letters of approval at 3/8 but some like LP contradict it by selling 5/8 structural rate @ 16/24 told me they have bucking issues at 3/8. LP and most Engineered is glue laminated fiber junk, I'll take T1-11 with a ventilation gap behind it any day of the week. Roy O Martin one direct makes a good product I use 5/8 way cheaper than engred, no osb sheathed, or barriers. The reason why most siding fails early is due to a lack of understanding of vapor transports and hygothermal mass they don't teach in engr school. The whole vapor barrier and retarder, house wraps, smart or dumb wraps, is a mess I don't follow any of. 

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