I have been asked to install bevel siding and T111 siding on a new house, the bevel siding is pre primed redwood, the T111 is not primed. My question is should I prime the back and edges of the T111. I have never seen this done before but can’t understand why it wouldn’t for the same reasons that you would back prime any other siding.
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Replies
T1-11 is an exterior grade plywood.....not the most attractive siding in the world.....but backpriming shouldn`t be necessary.
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If you`d like to discuss topics other than home building, come on down to the Woodshed Tavern. Great bunch of guys and gals letting off a little steam about everything and anything. Its not a special club, but.....as of Monday, March 14, the Tavern folder will go behind an access wall. Only those who request access to this folder by contacting [email protected] will be able to view and participate in discussions there.
Maybe a dumb question.... but I seem to be on a roll with them tonight, so why quit now.
How do you flash windows with T-111? I built a great little kids playhouse last week for a GC/friend of mine's kids. No actual windows.... just holes with trim around 'em. But it got me thinking.
That's a helluva good question. A detail I've seen several times... they nail the T1-11 directly to the studs (maybe over Tyvek but definitely not over sheathing), nail the window to the T1-11, and then run trim around the window. There's nothing to keep water from going in behind the flange except... yeah you guessed 'er... caulk. With the groove patterns you get these nice water channels right into the house. Caulk those too.
I'm starting a job shortly where the entire house is done that way. I've told the owner to expect major issues.
Seems to me that if you planned ahead you could trap Z flashing under the top edge of the window opening, then work the window in under it. Might need to cut the siding a bit short on the top side, then install a spacer below the flashing, to make it work right.A lot of planning, though, and that's not typical for a T111 project.
I agree with DanH, We have gone to the extra work of installing a "Z" flashing over the window which is covered by the trim. It's not that hard with advance planning. As we all know depending on caulk becomes a chronic pain. You can still caulk above the trim but you're not depending on it. The "Z" flashing we made up lapped over the window flange.
Dieselpig,I used T1-11 on Townhouses about 20 years ago but we sheathed first and installed the windows on top of the sheathing and then put drip cap on and sided over the drip cap.I built a couple sheds that only had two or three windows and we weren't using sheathing so I put 2x4's on a flat nailed to the king studs and 2x4's on a flat at the bottom of the sill nothing at the top because of the headers and then nailed the windows right into the framing and trimmed around the windows with 5/4 x 6 and nailed a drip cap on top of the 5/4 and then nailed the T1-11 on up against the sides and bottom of the window and on top of the drip cap.It's extra work but your not just nailing the window flange on top of the T1-11 and casing over that and relying on caulk with no drip cap.Joe Carola
Don,
I think its a combination of the dripping from the roof and the lack of proper preparation. Part of the front of my house has T111 and it looks fine. Its almost 27 years old and has only been painted once, but is well protected from water.
When I built my garage, we ordered the trusses for a 20" overhang. We did not measure them when they were delivered, framed up the walls and got ready to place the trusses. Well guess what ... only an 8" overhang :( Called the truss plant and they offered them to me at almost 60% off if I would keep them. At the time I did not think the small overhang would be a big problem, but now I see it was a mistake. The front and back gable ends of the garage have about a 16" overhang and there is absolutely no problem with the T111 there. I am getting ready to extend the overhang to solve the dripping problem. Gutters are not an option, too many trees. I am leaning towards just replacing the T111. Bill Koustenis
Advanced Automotive Machine
Waldorf Md
D........Flashing T111 windows.... I tried useing the J channel that DW's use when they wrap interior windows with drywall that butts the window. Over a year later and I took apart a section ,found no problems, makes a clean looking job with no caulking and is paintable also allows for expansion/contraction with less worry when cutting sheets for an exact measurements when windows are not perfectly plumb or level.
I`ve done only a few projects using T1-11....when installing over sheathing, I`ve flashed as normal....when installing over bare studs, I install windows and doors prior to product.
The housewrap/roofers felt and T1-11 overlap the flanges and trim is applied atop the siding. Caulking is applied with each step.
Its not a great product for homes....but for sheds I believe its ideal.
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If you`d like to discuss topics other than home building, come on down to the Woodshed Tavern. Great bunch of guys and gals letting off a little steam about everything and anything. Its not a special club, but.....as of Monday, March 14, the Tavern folder will go behind an access wall. Only those who request access to this folder by contacting [email protected] will be able to view and participate in discussions there.
Install the t-111 as the sheathing/siding combo it is.Above the windows...Cut the t-111 along the -top- edge of the window flange. (Window not installed yet.)(Set the window in the opening, and mark along the top edge of the flange. Then remove window.)Remove that piece, and insert a piece of Z flashing under the t-111 above the cut.Caulk that to the upper piece of t-111. Caulk all inside corners/edges of the hole left by the piece of t-111 that you removed. Then reinsert the removed piece. (Best if you prime the bejeeezus on the removed/replaced piece before reinserting it. Also, prime the bottom of the piece above, before you install the Z flash.)When you install the window, make sure that you work the top flange under the Z flashing that you installed earlier.Caulk the rest as usual, and flash/trim as usual.
A person with no sense of humor about themselves, has no sense at all.
P.S. when we did this, we made our own Z flash for that particular detail, so that the bottom leg of the flashing was at least an inch to two inches long.You may be able to find the Z flash big enough on both legs, now.
A person with no sense of humor about themselves, has no sense at all.
I would prime the edges.
That is often where you start seeing paint failure.
Tim,
I am getting ready to replace the T111 that I used when I build my 24x24 detached garage about 16 years ago. I did not prime the edges or back prime at the time, but you can bet your life I am going to this time. The lower foot or so on the two sides of the garage are falling apart. They do get water splashing when it rains because of the lack of gutters, but I think that if the siding had been properly prepared before installation, I would not have had much of a problem. You migh also want to look at my recent thread on Hardie Panels, they look like a nice alternative, but there are limitations.
http://forums.taunton.com/tp-breaktime/messages?msg=58993.1
Bill Koustenis
Advanced Automotive Machine
Waldorf Md
I am getting ready to replace the T111 that I used when I build my 24x24 detached garage about 16 years ago. I did not prime the edges or back prime at the time, but you can bet your life I am going to this time. The lower foot or so on the two sides of the garage are falling apart. They do get water splashing when it rains because of the lack of gutters, but I think that if the siding had been properly prepared before installation, I would not have had much of a problem. You migh also want to look at my recent thread on Hardie Panels, they look like a nice alternative, but there are limitations.
My shed has exactly the same problem. It's also about 16 years old. I believe the T-111 is absorbing moisture at the base because of its proximity to the ground. The surface is very well protected with paint so I don't think a little splashing is causing my problem.
It does make me think that T-111 shouldn't be used on actual houses. I sure wouldn't. And when I get around to repairing my shed, I'll probably use CDX and cedar shakes.
-Don
Hey Bill, have you totally given up on the Hardi-panel?I'm still a-mullin' it myself. But if I go with the T-111, I'll do it thus: prime all the edges, and use a water table at the bottom against the slab (i.e., a PT 2x8 flashed over, upon which the siding sits)..this will keep the panels off the ground by 8" and it will allow me to build 9' walls and still be able to use 8' panels to side them ('round here no one sells 9' T-111 panels). Oh, and you weren't going to use OSB T-111, were you?BTW, the point of using T-111 as sheathing requires it to be applied first--windows are inserted OVER the siding, then self-stick flashing is applied OVER the flanges; trim over that. Yes, you've got to caulk the channels over the trim and over any belly bands. Use the best caulk you can buy.
It could be time consuming. But I think priming it would be worth while. I think I would talk the paint vendor into tinting the primer something closer to your finish color than the white the primer starts out. They will whine but, who cares?
Of course a lot depends on how long you want it to last.
I've been through the T-111 learning curve. They're right, it's really intended to be a cheap sheathing and siding combo. But even at that, it's worth back priming, especially if you back prime easy and cheap...try cutting boiled linseed oil with turpentine 50% and putting that on the back. Or even upping the linseed % to 60-70%.
For the edges, do them while the sheets are stacked. Paion in the butt to prime cut edges as you side, but probably worth it.
As far as flashing, I had good luck just relying on caulk where a 12" eave protected...but where there are minimal or no eaves, go the pre-planned Z flash and trim route.
Edited 6/6/2005 9:12 am ET by johnnyd