Attaching drywall to OSB with GG in-between

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howiedrum
Posts: 36
Joined: Thu May 25, 2017 8:09 am
Location: Arcata, California USA

Attaching drywall to OSB with GG in-between

Post by howiedrum »

My builders started attaching the 5/8 drywall to my 3/4 OSB with gg in between today. The studs are 16 OC. They are using 1-1/4 inch screws, so they are not getting into the studs, only the OSB. I told them to not put screws in the field. So they just did the perimeter. See photo.
IMG_4695.jpg
My builder is concerned about the weight of the OSB. He wants to add screws in the field.

My questions are:
1) Should they use 2" screws so they actually sink into the studs or is just into OSB ok?
2) If sinking into studs is required, should they sink into the studs in the field of each panel too or just in perimeter?
3) If sinking into studs is not necessary, is it ok to put more screw in the field as my builder requested?

Thank you,

Howie
Paulus87
Senior Member
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Joined: Sun Mar 02, 2014 8:42 am
Location: Wales, UK

Re: Attaching drywall to OSB with GG in-between

Post by Paulus87 »

howiedrum wrote:My builders started attaching the 5/8 drywall to my 3/4 OSB with gg in between today. The studs are 16 OC. They are using 1-1/4 inch screws, so they are not getting into the studs, only the OSB. I told them to not put screws in the field. So they just did the perimeter. See photo.
IMG_4695.jpg
My builder is concerned about the weight of the OSB. He wants to add screws in the field.

My questions are:
1) Should they use 2" screws so they actually sink into the studs or is just into OSB ok?
2) If sinking into studs is required, should they sink into the studs in the field of each panel too or just in perimeter?
3) If sinking into studs is not necessary, is it ok to put more screw in the field as my builder requested?

Thank you,

Howie
In my opinion either is fine, but no need to use so many screws. You could use longer screws and screw every 16" horizontally and vertically.

Paul
Paul
howiedrum
Posts: 36
Joined: Thu May 25, 2017 8:09 am
Location: Arcata, California USA

Re: Attaching drywall to OSB with GG in-between

Post by howiedrum »

Thanks Paul for your opinion. I spoke to Ted White of soundproofingcompany.com and he said it is critical to put screws in the field along the studs, spread 16 inches so the gg spreads properly. That is how it is designed. The screws do not have to be longer and screwing just into the OSB is fine.

Unfortunately for me, those two panels have been compromised.
Gregwor
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Location: St. Albert, Alberta, Canada

Re: Attaching drywall to OSB with GG in-between

Post by Gregwor »

There is a screwing schedule that needs to be followed for safety reasons.

Also, if that were my build, I would have sealed the heck out of every seam of the OSB before putting up the drywall. The odds are against you that the sealant will be perfect on only the exposed layer of drywall.

Greg
It appears that you've made the mistake most people do. You started building without consulting this forum.
atomicus
Posts: 39
Joined: Thu May 03, 2018 10:44 pm
Location: South of England, UK

Re: Attaching drywall to OSB with GG in-between

Post by atomicus »

howiedrum wrote:Thanks Paul for your opinion. I spoke to Ted White of soundproofingcompany.com and he said it is critical to put screws in the field along the studs, spread 16 inches so the gg spreads properly. That is how it is designed. The screws do not have to be longer and screwing just into the OSB is fine.

Unfortunately for me, those two panels have been compromised.
Isn't there a contradiction there... "critical to put screws in the field along the studs" but "screwing just into the OSB is fine?" So you DO or DON'T have to screw into the studs in the field?

How are your panels permanently compromised? You can just add more screws in the field can't you?
howiedrum
Posts: 36
Joined: Thu May 25, 2017 8:09 am
Location: Arcata, California USA

Re: Attaching drywall to OSB with GG in-between

Post by howiedrum »

How are your panels permanently compromised?
I am no expert but you don't want your assembly be too stiff. So if you put a bunch of screws in the field, you could over do it. Not have any play between the sheathing.

You can just add more screws in the field can't you?
Mainly you want to spread the Green glue between the OSB and drywall. What Green glue retailers like Ted White say is to basically screw the drywall in following the normal schedule you would use when installing two sheets of drywall. The OSB is solid enough so you don't have to go into a stud, but we just followed the normal schedule for two sheets of drywall, putting our screws in line with the studs,
howiedrum
Posts: 36
Joined: Thu May 25, 2017 8:09 am
Location: Arcata, California USA

Re: Attaching drywall to OSB with GG in-between

Post by howiedrum »

Also, if that were my build, I would have sealed the heck out of every seam of the OSB before putting up the drywall. The odds are against you that the sealant will be perfect on only the exposed layer of drywall.
Good advice. When I brought this up the builders said they put caulk on each stud before attaching the OSB. I would have felt better if they then put more caulk on the seams but at the time I wasn't sure whether it was necessary and I had been fighting with the GC so I let it go. I will know soon if it is an issue, but if I were doing it myself I would have definitely caulked those seams. The good thing is the closest structure to my studio is 100 feet away!
atomicus
Posts: 39
Joined: Thu May 03, 2018 10:44 pm
Location: South of England, UK

Re: Attaching drywall to OSB with GG in-between

Post by atomicus »

howiedrum wrote:
Also, if that were my build, I would have sealed the heck out of every seam of the OSB before putting up the drywall. The odds are against you that the sealant will be perfect on only the exposed layer of drywall.
Good advice. When I brought this up the builders said they put caulk on each stud before attaching the OSB. I would have felt better if they then put more caulk on the seams but at the time I wasn't sure whether it was necessary and I had been fighting with the GC so I let it go. I will know soon if it is an issue, but if I were doing it myself I would have definitely caulked those seams. The good thing is the closest structure to my studio is 100 feet away!

How has the OSB been attached exactly and how are all those screws in the plasterboard missing any in the OSB? Are they just staggered?

Also, I couldn't see if much of a gap has been left between the OSB sheets? I've seen it recommended that OSB has a 1/8th" when putting sheets together (for expansion) but I don't know if that's necessary when using like this, or if that's just more for external use?
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