Air sealing T111 to use as siding and air barrier
This is for a garage build in Central NY CZ6 that will be heated in the future.
Original plan was for 2×6 walls with fluffy insulation, taped OSB sheathing, reclaimed polyiso, strapping, steel siding.
Prices of OSB and Steel have more than quadrupled in the last year.
T111 is now the same price, or cheaper than 7/16 OSB, its common to see on garages and sheds around here, One shed I used in on nearly 30 years ago, is holding up just fine.
Is there any reasonable way to detail it to act as an air barrier, and finished siding?
The part that has me slightly confused is the vertical seams, is there some sort of double sided tape that could work?
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Replies
Just air seal the T1-11 to the framing so that the T1-11 itself is the air barrier instead of whatever you put over the exterior of it. The easiest way to do this would be to put a bead of sealant around the perimeter framing immediately prior to hanging the T1-11 panel. I would use a polyurethane sealant for this application. If you air seal the back of the T1-11 to the framing in this way, the vertical channels on the front don't matter. If you use the T1-11 as finished siding, you need to paint it.
You may want to consider regular plywood too. Plywood has often been the same price as, or even cheaper than, OSB lately. Regular plywood is usually considered to be better than OSB, but it used to be more expensive so using OSB was a cost saving option. If that cost savings goes away, there is no longer any reason to OSB in place of regular plywood.
Bill
I have used this product a few times acting as both the sheathing and outer siding (particularly for out buildings). I always found it difficult to figure out how to flash/tape the windows and doors. What approach are you taking for this aspect of construction?
Building will have large overhangs (2') I'll be doing a metal head flashing, and just tube sealant for the t111 to framing, then same for windows to framing
I would put up a heavy duty house wrap such as Tyvec commercial over the framing and under the T111 and detail that as your air barrier. Seal that to your framing with acoustical caulk around the perimeter of the walls and rough openings and tape any seams. You can now flash your windows to this layer but I would add a kickout flashing on the bottom to channel any water past the T111.
This will get you a decent air barrier and a WRB if you ever decide to install other siding over it.