Introduction to T1-11 Plywood Siding

T1-11 Siding
Ever heard of it? If you're a contractor, of course you have. If you're a do-it-yourselfer, maybe not. If you haven't heard of T1-11 siding I wanted to give you a brief introduction and tell you why you might want to use it on a project.
T1-11 type siding generally comes in 2 different forms. One is based on Oriented Strand Board (OSB) and the other is plywood based. You can get 4x8 sheets of either type at the local lumber store. The OSB type has a wood grain look embossed on the exterior of the sheet, whereas the plywood based T1-11 has a rough- sawn wood appearance on the exterior. Both types have vertical grooves 8 inches on center.
The plywood type T1-11 is what I used so that's what I'll be talking about in this video. I like it because it has 5 plies and is about 5/8 inches thick. The edges of the sheet are half lap joints so that when it is installed you can't see the seams between sheets.
T1-11 is used on all types of residential and commercial buildings. Everything from sheds, to houses, to restaurants and small office buildings. I used it to re-side a house recently and wanted to show you how it looks. Since so many houses have vinyl siding on them, T1-11 gives a unique look. Also, at $33 for a 4x8 sheet the price is reasonable.
Before I show you my project, I wanted to share some things I did to the T1-11 before attaching it to the building. Since this is a wood product I wanted to paint all sides before installing it. This may seem like overkill, but I wanted to protect against future water damage. Just think of this as insurance. I also painted any edges or cuts that I made.
A good paint for the finish coat is Valspar Duramax available at Lowe's. It's a paint and primer in one and is great for the exterior side of the siding but it is a bit expensive. With that in mind you probably want to buy and use a regular primer for the back side of the T1-11 sheet. Regular primer will still be over $20 a gallon but will save you some money when compared to the expense of the Valspar Duramax.
Another thing you will need is caulking. The one I like is called OSI Quad Advanced Formula Sealant for windows, doors, and siding. It is paintable but comes in various colors and is flexible even in very cold temperatures and costs about $5 per tube.

Now, here's some footage of my project. You can see we set up some saw horses and painted everything before we installed it. We painted the back of the siding with regular primer and we painted the front with Valspar Duramax.

To make things easier and safer, we rented some scaffolding from Home Depot. Other than that we just worked across the house, one 4 by 8 sheet at a time. We removed the old rigid insulation and replaced it with 2 inch rigid insulation under the siding and taped the joints. After installing the trim, we caulked the top but left the bottom open so moisture wouldn't be trapped.

Well, that's it for now and I hope you enjoyed this intro to T1-11 siding. Thanks for watching.

[ayellowbeard]

5 year old video I know but thought I'd chime in nevertheless: T1-11 also comes in a "rough-sawn plain textured face" version (no grooves). We used it on our house and added battens for a board and batten look.

[KJKP]

Painting and protecting the exposed ends and cuts is actually very important. T1-11 can begin to have significant problems in as short as 10 years if not properly installed. Proper installation protects all exposed cuts and ends from water exposure. T1-11 can swell with water.

[ronaldshane]

Where I work at we used 5/8” x 9’ cedar t111 siding. It works great . We used it for years. Good stuff.

[dlhiles]

Thanks for this! I didn't know what kind of siding I have on my house and now I do.  Next I have to figure out how to fix some rot I've discovered on my garage wall.

[HollondonSCOEM]

Very nice intro SyberPrepper and a very good video. I've used this on part of my house lately and it looks brilliant. I used Tyvek insulation sheets underneath and the T-11 ply over it for our back veranda. Looks brilliant. Great you posted this up.

[steveh]

Rent the scaffolding is a great idea, thanks for the video

[MarkSmith-zfqk]

Thanks for taking the time to make this video. Very helpful.

[lukewiggins]

Those sliding glass doors look just fine.

[SyberPrepper]

sweatyfish2007, No problems putting the T1-11 over 2" foam.  I think I used 3 1/2" screws.  My studs were 16" on center and I put screws every 12" or so on all studs.  Again, no problems.  If there was a stud where the tongue and groove overlapped I would put a screw.  I used lot of caulk to make sure no water could get in.  It has held up very well.

[charliefoxtrot]

Thank you for the intro to T1-11. I'll be using it in a couple of weeks on our new house, and didn't really know that much about it. Cheers!

[andyfer]

Thanks for a very informative video. Why isn't a housewrap required? Is the rigid foam waterproof and airtight? Also since the fasteners go through the rigid foam, do they get adequate support? I would think that the foam doesn't provide much support and it would be like installing the siding with an air gap from a structural standpoint.

[SyberPrepper]

Ny plantings: Looks like your replies for YouTube are turned off, so I'll reply here.  I think the only way to replace part of a T1-11 board would be to use some type of trim to cover the joint and lots of caulk. I'm thinking board & batten type of thing.  However, I think it would be hard to keep the water out over the long term, especially a chevron pattern. Probably better to special order the 9 ft boards and replace them.  Be careful taking the old ones off and use them as a pattern to make replacing and matching easy.

[skorpyo]

I have plywood sheets behind my t1-11 every other 5 feet. So theres a gap that 5 feet. Rotting bottoms. So im thinkin i ll hv to fill that gap w sheets so i can properly align a z channel.

[geirbalderson]

I agree that T1-11 has a nice post modern vibe. However, unless it is vigorously primed, painted and maintained it will deteriorate due to the open ply grooves. I would suggest a better siding is solid siding such as James Hardie fiber cement? It has a much longer life and will not warp or delaminate. The horizontal siding and or board and batten appearance is quite nice and more worry free.

[erichavemann]

Thanks.  The first time I knew the siding on my house was called "T1-11" was when I got an estimate from a contractor to powerwash and paint (or stain) the house.   Now I have to decide which route to go and what colors/products to use.  The house was built in 1983 and despite exposure to rain, harsh Poconos winters, and (to the best of my knowledge) the original stain, the siding has held up well.  Can't say the same for the 1/4" plywood soffits and pine 1X12 fascia, much of that has to be replaced as well.

[eaglelandedjupiter]

this was a real good video on how to install wood siding

[SyberPrepper]

Hey Brian,
Great tips. Thanks for posting.

[billparsons]

The horizontal trim board at the splice point has always concerned me as a water collection point. The vertical groves 8" oc are perfect channels for water to get behind the trim even when loaded up with caulk. I suppose you could rip an angle on top of the trim board; but ... I'll assume you've got some Z-bar behind the trim too. Thanks for the video.

[williamb]

Looks great, would you by chance still have the paint and trim colors?

[johndavis]

I have a question, If my house is all sealed up well already and it has really old but fiber cement shingle siding that is smooth, could I install this directly over that?  if so would I still install a vapor barrier over the old fiber cement siding?