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bjqq 01-22-2013 03:23 PM

Newbie needs your advice on OSB wall sheathing
Hello everyone, newbie needs your advice on OSB wall sheathing

I have two questions on OSB sheathing, should seams/gaps be between sheathings? Is it normal to leave cracks/holes on sheathing?

After our builder had sheathed our new house with OSB, we found some seams between sheathings, and holes/cracks around window frames. We asked the builder to patch them, but he said that the gaps were left to allow for future expansion, and the holes/cracks were not big deal as there would be fiberglass insulation to cover them.

Both my husband and I are newbies on building, so we have no idea on what he said. Those gaps/holes really don’t matter insulation? And those cracks/holes don’t need to be patched?

Any advices would be appreciated.

P.S. I'll post some pics once i figure out how to.

md2lgyk 01-22-2013 03:31 PM

How wide are the seams?? How big are the cracks? It is typical to leave some small space to allow for expansion. Holes around windows are better sealed with spray foam, not insulation.

bjqq 01-22-2013 03:46 PM

I hope you can see the following pics




joecaption 01-22-2013 04:00 PM

I'm not there to see the whole big picture but it looks like someone messed up on the stud lay out and added a second 2 X 4, then never even nailed them together.
One looks like he used a scrap piece that got tore up but the fork lift.
None of what I see is exceptable.
If that's the kind of work he thinks is exceptable I'd very scared to let him do anymore work.

bjqq 01-22-2013 04:00 PM

Thanks for your reply, Please see the pics, they are not all, just some of them.

the gaps sounded reasonable, but the holes don't need to be patched?

joecaption 01-22-2013 04:02 PM

Whole section needs to be replaced, not just patched.

DannyT 01-22-2013 04:10 PM

looks like another hack job. it may be the contractors sub that did it but it is still not a professional job by any means.

bjqq 01-22-2013 04:49 PM

Thank you all for you inputs.

We will discuss with them seriously.

woodworkbykirk 01-22-2013 08:33 PM

1/8 to 1/4 is perfectly acceptable for horizontal joints as mentioned for expansion.. what has me curious is why the sheets are stood up. locally that woiuld never pass an inspection.

having a slight gap at vertical joints when a wall is built in sections then stood is sometimes ok. by keepin the sheet back from the edge of the stud makes it so the two sheets dont get fetched up on one another when stood.. allowing the two studs that will be laminated to get naileed together solid.

its also possible the cut man didnt have the blade set deep enough on the saw which is causing the ragged cut

Gary in WA 01-23-2013 08:45 PM

I recommend caulking the stud/OSB joints, and at the plates also, to stop air infiltration/exfiltration, pp.21; Especially with air permeable insulation; fiberglass, rock wool, etc. Though, north of me they vent the cavities, you wouldn't need to patch the holes- lol. Read the ink stamp on the sheet interior face- "sized for spacing"; horizontal application in Canada for these grades, Table 2: Notice spacing gap after Table 3.

In the U.S.- either upright or horizontal with shear blocking (if required).

Be sure there is a gap or you will have problems;

And be glad your OSB is applied vertically; "Yet, there is one simple aspect of this technology that many people do not understand, namely the placement of OSB boards horizontally or vertically. Some “scientists” advise holes and gaps between OSB boards to accelerate “drying” not realizing that actually they promote wetting of the wall. Thus the construction practice goes towards another trap. Horizontal placement of OSB improves (marginally) racking strength allowing the usage of 3/8 inch thick board instead of ˝ inch while destroying airtightness and effectively all aspects of hygrothermal performance.
Yet, the solution is simple, use only vertical placement of the OSB boards. Vertical placement provides most joints on wood studs and ensures long-term OSB performance and effectively durability of the wall." From;

IMO, the gaps between studs is not near as important that the wall is out of plumb the width of the gap between plates just above the studs. Get a few of those and your drywaller will scream...
See if they stuff fiberglass in the window gaps to framing, you will know he doesn't care/doesn't know; read just below #8:

Insulate your rims with foamboard/canned foam or pay extra to have it done; 2nd floor rims also;


bjqq 01-23-2013 09:57 PM

Thank you all for your kind comments. I downloaded the pdf files from the links and will go through them. Thank you Gary.

joasis 01-24-2013 07:32 AM

No, the gaps shown in the pictures are not acceptable. Since he probably will refuse to do anything, you need to grab a case of low expansion foam, or at least caulk, and get might insist on Tyvek house wrap also. And don't let him batt it. Insist on cellulose. Or if you could, spray foam it.

The point is to stop air and water infiltration. Not provide a path.

scottktmrider 01-24-2013 02:28 PM

Room for future expansion.thats funny sure your contractor wasnt a used car salesmen before he started building?If he does rough work like this from the start you might have a long tuff road.Stay on his work take pictures and keep an eye on him.

Gary in WA 01-24-2013 03:38 PM

Judging by the pictures, I almost hate to ask for more pictures of the housewrap (WRB) after it is up.....
But that would lead to more pics of the siding and insulation, before drywall. I only presume the electrical, HVAC, plumbing are correct since there is less room to error in those fields because they are watched more closely. (Though exceptions exist).
This will give you a heads-up before it happens, what type of siding and where are you located?


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