Ok, I'm building a 10x12 foot outdoor shed on skids. I've got the floor done- notwithstanding some "gotchas"- like forgetting to measure and trim the rim & floor joists to length first (a 2x6x12 is actually a 2x6x 12.5, 12.25, 12.65 etc), placing the floor joists 16 inches OC from the ends of the rim joists rather than the OC of the first floor joist (realized there was a problem when my floor decking, 4 x 8 PT ply, didn't line up). grrrrr.....
Anyway, now I'm doing the walls. But I'm having trouble understanding what my stud lengths should be. I'm doing four exterior walls, all the same hieght, and I won't be finishing the interior. I want to use
4x8 T-11 siding, and would like to use all 8 feet of length.
I've found plenty of info online about how to frame, but little having to do with measuring / cutting studs when using exterior siding. They all just say to use 92 5/8 studs, which will make the wall 96 inches when you are done. But...
My Sill plate= 1 1/2 inches Top plate= 1 /12 inches Second top plate= 1 1/2 inches my flooring = 3/4 inch pt plywood.
That's already 5 1/4 inches. If I use 92 5/8 pre-cut studs, I will be short somewhere. And do I extend the siding below the 3/4 ply? If so, by how much? How about at the top?
92 5/8 precuts actually yield a wall 97 1/8 tall. As you have figured out, that doesn't work with 8' t-111 *the length is really designed to work on the interior with drywall.). You can probably get 10' sheet goods. Or else, figure out where you want to start your siding (bottom of floor joists?) and figure out a stud length that works with
8'.
I'd sheath it from the bottom of the floor joists up to the top. Cover everything. An eight ft tall sheet of t-11 will make plenty of head room even when you loose teh few inches covering the 2x6's at teh bottom.
So. lay three 2x? flat on the floor on the edge. Measure from teh bottom of the 2x6 floor joists and establish an 8 ft mark. Now measure from the top of the three 2x? that you dropped on the floor to that eight ft mark, and that's your wall stud length. Make sense?
Oh, and be more careful laying out your studs than you did with the floor! Don't forget corner overlaps for the T-11, taht will offset the studs a tiny bit.
That is the kind of mistake you make once, then never forget 'cause it is such a PITA to fix.
another gotcha to add to my list- thanks! I'll NEVER pre-build anything that is going to be sheeted w/o making sure the studs line up at sheet seams just right.
lol... maybe one day soon... Thus far it has been measure twice, cut it once, re-measure and find that the 12' rim joist you just cut was slightly cupped so it's now 1/2" short. No problem, just cut the opposite rim joist to match the shorter length- except that now your
16" OC measurements are all out of whack. Even more so since you forgot to account for the decreased spacing between the first two joists. Too bad I didn't find out until after I installed all 20 joist hangers :-( Live and learn I guess...
Thanks. I've read three different "beginner" type guides to framing, and not one has gone out of their way to make this basic concept clear.
Where would I find 9 or 10 foot sheet goods? I'm in central Texas & HD and Lowes are pretty much the only game in town- everything they carry is 4 x 8. The only place I've found where I could get lengths over 8 feet would have to do a special order, and would have to order at least one pallet.
A couple of follow up questions:
T-1-11 is some pretty thin stuff... how does one nail it up? To my credit I did get the plywood backed version, not the OSB- but it still looks pretty flimsy to be hitting with a hammer. Screws every 6 inches along the perimeter, and 8 inches on the inside?
Will I have any problems putting the non-pt T-1-11 over the PT 2x6 rim joists? The whole floor frame is on three 4 x 6 skids, so I suspect not... but at this point I hate to assume anything...
It was fresh on my mind because I bought some pine boards a couple days ago, and the ends were cut at about 70 degrees instead of a square 90. I would have been in trouble if I hadn't squared up the ends.
Most any lumber yard should have 9 foot sheets. There's bound to be one somewhere in town. Even Home Depot and Lowes should be able to order them for you.
If 8 foot sheets are your only option, just cut your studs to 89.25". With two top plates, a sole plate, and a 3/4" plywood floor, this would let the plywood overlap your floor joists by 1-1/2". This will let you nail the siding to the floor joists so the building doesn't blow off the floor, and will keep water from seeping under the siding onto the floor. You should end up with about 94" of headroom in the shed this way.
Of course, this will leave the lower part of the floor joists exposed. Since you have pressure treated joists it shouldn't be an issue, but you may want to paint them as a little extra protection.
Otherwise, you can install a "skirt board" the same thickness as the siding around the bottom of the building, and install "Z-flashing" between the bottom of the siding and the skirt board. This will direct any water running down the wall outward, instead of going back behind the skirt board. Z-flashing is usually available at any home center.
T-111 is only as strong as the thickness in the grooves. You'll need to look at the span ratings on the sheet to ensure the sheet you buy is rated for your stud spacing (typically 16" OC).
I use an pneumatic framing nailer, but I've done it by hand as well. It just takes longer.
I prefer to build the walls flat on the floor, including the plywood sheathing, then tilt it up, plumb and brace, then nail it in place. It's easier to build and keep things square this way, though you'll need help to tilt up the walls. If you're working alone, it might be easier to frame the walls first, then install the siding. You might find it helpful to screw a board to the joists (at the correct height) so you can rest the sheets on it while you nail it to the wall. Then unscrew the board and move to the next sheet. Sometimes you have to get creative when working alone.
You'll be nailing to the studs, so the studs are what you're really hitting against. However, if the plywood seems flimsy, you better double- check the span ratings stamped on the plywood to make sure it's the right thickness for your stud spacing. You may need to return it for the right thickness, or add studs to achieve the required spacing. Or, you can buy plywood sheathing for your stud spacing, and just use the T-111 as siding.
That would work fine. Nails would be better than screws in this application, as screws are brittle and tend to break under stress, whereas as a nail is softer and bends (but won't break).
Thus far I've done ok with my older model Bostich N80SB. The only problem has been that the "nose" of the gun is to big to fit into the channels of the t-1-11. So I have to come back around with a punch to sink the nails in the last little bit. Please tell me I am doing it right- you *do* nail t-1-11 through the channels correct? What's the best way to handle where the sheets meet? They don't really overlap much, so I am doing some nails in the channel, and some through the face of the adjacent sheet hoping to catch the stud.
look on page 12 of 19 which shows how it is nailed. And, no, not in the groove! This document also shows corner framing techniques nicely, good artwork.
I don't nail into the channel. I nail through the thickest part of the panel.
Then they must be double dipped hot galvanized, not electroplated. If they are good for PT, it should say so on the box. Otherwise, they will deteriorate.
You nail into the studs, whether that falls in a channel or not. Given a choice, I'd prefer to nail in the main body of the panel since it's thicker than the grooves.
The T-111 I've used in the past had shiplap edges that overlapped where they meet. I overlapped the edges, then nailed the top sheet down.
If your sheets have square edges, just butt them up so they line up over the middle of a stud. Angle your nails in slightly from each side to be sure you catch the stud.
Interesting. I've always heard the sheets were only as strong as the thickness in the grooves. Seemed to make sense, though in all fairness, I did recommend checking the ratings on the sheets too. :)
Still, I wonder if that's only for sheer strength? If it was being flexed in and out, say from a tornado or wind causing pressure differences, would the grooves would weaken the sheet more? Doesn't really matter as the building would probably be toast by then, but it makes me wonder.
per APA, the nail / sheathing interface determines the system strength.
Nails give higher values when nailed through the thicker section. The values I'm speaking of are for shear (in plane) loading.
The out of plane loading values probably aren't effected that much (if at all) by presence of the grooves. If the sheet has a decent nailing schedule, the bending (flexing) out of plane would be pretty well restrained.
I want to thank everyone for their input. I had an opportunity to speak with a engineer at Georgia Pacific and we discussed the nailing issue at length. Obviously you need to nail through the thick part of t1-11 to get maximum strength. However, the channels are at 8 inches OC. This puts a channel dead center on each stud @ 16". The groove is 3/8 inch wide, but with the beveled edges it is more like
1/2 inch. Also, I've found it necessary to nail at least 1/2 inch from the groove to keep from crushing the laminates. All this doesn't leave much room to catch a stud, even when nailing at an angle. He told me that there was much discussion about this after hurricane Andrew hit Florida and revealed that allot of t1-11 wasn't nailed to anything.
He told me the solution is to rip 3/8 inch from the overlap edge of the first sheet. This insets the grooves relative to the studs enough to reliably nail though the full thickness of 303-6 T1-11, even when using a nail gun. Notice that the APA's E30T Wall Construction Guide shows how to nail a shiplap edge (by nailing at an angle), but shows nothing about dealing with channels in the field of the sheet. You'd infer that you'd just always nail at an angle. But if you look closely, the illustration shows the underlap is inset slightly. If you don't rip 3/8 from your first sheet, 9 times out of 10 the underlap will cover the entire stud.
Gee, I looked at the APA guide and in figure 17, page 48 they show nails on either side of the groove of t-111. Course that looks good on autocad, but in the real world, studs do not wind up being placed so precisely that you have the luxury of two nails side by side. Nor can plywood be placed that precisely. (plywood manufacturers recommend a 1/8" gap, yet still make plywood 48" wide, so you tend to start gaining on the layout anyway.).
But what was your engineer talking about ripping 3/8's off of the first sheet? Doesn't really seem practical to me. I would bet you money that in is almost never done. T-111 is a low end residential siding product. Most carpenters don't even know that you should cut
3/8's off of the first sheet, and if they did, they'd ignore it. Manufacturers like it this way. If there is ever a hurricane that results in collapses of buildings sheathed in T-111, all they have to do is point their finger at the installers. This happens time and time again in the construction materials business. Providing vague, incomplete,or no instructions with the product is not an accident, it's a carefully thought out strategy.
Back to your shed. I would go ahead and nail it in the grooves. It's just a shed, and the wind would probably pick the whole thing up before the shear walls fail anyway. Also, to deal with your sheet length problem, another approach would be to add a wide 1x8 "belly band" trim around the bottom.
Happy Turkey Day all! Last post on this issue- I promise. Thanks again to everyone for their input.
I know I am belaboring this issue. I think it's because it offends my anal-retentive nature to have a question without an answer. But also, I'd just like to understand construction & make things the right way. I do realize that t1-11 is pretty low on the quality scale. It is designed for projects just like this- that's why they sell it at Home Depot. Groove vs. face? Who cares- doesn't matter when your are building dog houses and such. As marson mentioned- the manufacturers really don't care either. It's not in their interest.
PeterD- yes, in the future that is what I'll do- just offset the studs by 1/2 inch. Ripping 3/8 inch from a sheet sounds like a PITA
marson- I think we are referring to the same document, APA E30. The one I am looking at is the 2007 version E30U, but the illustration in yours should be the same. If you enlarge the diagram you will see a very small vertical space next to the right most nail. What the GP engineer was saying is that the diagram only specifies the nailing pattern @ the shiplap- not necessarily how you should nail in the field. Yes, he was talking about ripping 3/8 off the first sheet- on the clean edge, not on the shiplap edge. In the end I think I'll do what PeterD advised: just offset the studs a little- much easier. Thanks for the belly-band idea, that's what I will be doing. It should blend in nicely since I will be using 1 bys on the corners & around the doors and windows. I was loath to extend the t1-11 too far towards the ground- I've seen plenty of sheds with the bottom edge of the t1-11 rotted away. To prevent that I am using plywood not OSB & I back primed the sheets 36 inches with an alkyd primer. Finally, if I use z-flashing between the t1-11 and belly-band, I think I will have done all I can.
Steve Barker - lol... yeah, I can't argue with that.
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