Hello, I am building a garage and I used 7/16x4x9 osb for wall sheathing. I built 9′ walls so I
used 9′ osb and stood it up. the sheathing has been on for a couple months and it is exposed.
It is now buckling. it is pushed inwards between the studs but it does push out next to some of the verticle joints. can I fix this without replacing it or can I just hide it with vinyl siding?
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Replies
id like a nice finish. i do not have any joints that dont fall on a stud.
Yeah, some of the buckling will flatten out after you get it out of the weather. It's a question of how you do that, and whether you want to cover it temporarily to let it flatten before you apply the siding, vs installing the siding and hoping for the best.
Cover it with tarpaper or your choice of vapor barrier, it should straighten out.
blocking?
I have to say I don't use OSB. Do you guys who have posted think that when the OSB dries out it'll straighten out? Does OSB do that? That's an honest question, not a statement of doubt.
If I wanted to straighten out some of the bowing, I'd consider adding some horizontal 2-by blocking in the stud bays wherever it's buckled the worst.
When you nail up vinyl, you generally leave the nails loose so the vinyl can expand and contract. So the vinyl might float right over some of the not-too-bad wonky areas. But with the nails snugged tight it'll follow the dipsy doo's.
I know that vinyl is often installed over that fan-fold foam stuff. Would that help since most of the bowing is inwards?
Again, no real solutions from me as I'm not an OSB or vinyl guy. So all I can offer are some some ideas for you and the others to kick around.
If you don't think any of the above ideas will work, how about getting some inexpensive 3/4" strapping and nailing that vertically, right over the studs. Then nail off the vinyl to the strapping. That'll prevent any outward bowing OSB from touching the vinyl. Can you do that with vinyl or does vinyl need continuous backing? Again, just another idea.
Good luck with it!
Wow. I've seen a lot of uncovered osb and never seen it buckle on a stud wall. Is there something you're not revealing?
I think I listed everything. I dont know if its because I put it up vertically because it is 9' sheathing on 9' walls so I dont have any horizontal joints. The idea of furring the studs out might work. I think ill cover it with roofirng felt and lrt it dry for a while and see what happens. thanx to all who posted.
Spacing
If the osb was installed without necessary spacing it could swell and buckle. Try setting a saw with depth the thickness of the osb and running it along the joints. This may relieve some of the pressure.
I'd suggest Tyvek rather than tar paper. It can let water vapor exaporate through it, which tar paper can't do.
I think tar paper is a vapor barrier, it's not airtight. Also the osb is open to the inside, so it can still dry out. I don't think tyvek is needed on a typical garage, it's a two or three man job to install, and more expensive than felt (tar paper).
Tyvek is a PITA to install single-handed, but I've done it. And if I can then pert much anyone can.
With two people it's a snap -- probably easier than felt, since it won't tear.
Tyvek is still more expensive, but is it really better? I think not, but wadda I know...
Buckled OSB Root Causes
I'm seeing this in a band of construction from northern NY State through Michigan and Wisconsin. There are MANY contributing factors, but the #1 cause was your orientation of the OSB in the vertical/portrait position. New OSB from a climate controlled source is only about 4% moisture content. As the name implies, the wood fibers are "oriented" in a particular pattern that causes a 4'x8' panel to expand much more on the 4' width than the 8' length by a factor of nearly 4x as the wood equalizes to 9-12% moisture content, so those panels can possibly grow by 1/4" each. When you nail the entire perimeter, even if you spaced the panels apart appropriately, there is nowhere for the expansion to go but into the space between the studs.
The best practice to remediate the problem is to strip the panels off and reorient new panels. Warped OSB will be forever the shape it warped into. In addition, if they have sucked up a lot of moisture from exposure, condensation, or bulk water; the panels are no longer as structurally sound and are much more vapor permeable.
Possible temporary fixes are to cut relief kerfs in the panels and gusset them from the inside. You may also apply a furring strip outside under the siding to simply hide the visibility of the warp.
Matt
greatlakeshomeperformance.com