Why does everyone use OSB behind drywall?

[Mikael_L]

Had to test screwing into a chipboard and I didn't get a crater 3

That's about how it turned out in the chipboard I tested.

There's probably a difference between various chipboards in terms of how hard the surface and porous the core are. I think.

 

[emni0032]

Hello,

I am planning to set up a new interior wall to partition a space in the apartment. Approximately how thick will a new interior wall with a standard interior door in a frame be? Preferably a slightly thicker wall with gypsum/OSB and perhaps some insulation in between to dampen disturbing sounds. Is it enough to estimate about 10 cm thickness?

Best regards

 

[Poxeman]

We have the following structure in our walls and they feel stable.
13 gypsum
12 OSB
45x70 stud with mineral wool insulation
12 OSB
13 gypsum.
Total: 120mm

If it's about bathroom walls where you want to reduce sound, it doesn't hurt to use 45x95 studs.

 

[Demmpa]

One can roughly calculate the following for a standard wall:
Gypsum-OSB-stud-OSB-gypsum
15+15+45+15+15=105
At least the gypsum is 15mm without approximately 13mm.

Whether it is enough to dampen disturbing noise or not depends partly on what kind of noise it is.
Some noises go through almost everything.

 

[useless]

118 mm (70mm rule 2x11mm OSB 2x13mm gypsum). Check the standard dimensions for door frames and base it on that for simplicity.

 

[emni0032]

Thank you so much for the quick and good answers!
/E

 

[catherineb]

We have the following structure in our walls and they feel stable.
13 gypsum
12 OSB
45x70 studs with mineral wool insulation
12 OSB
13 gypsum.
Total: 120mm

If it's about bathroom walls where you want to reduce sound, it doesn't hurt to use 45x95 studs.

That's what we have too, but with particle board instead of OSB.

But I thought you always needed 49x95 studs in bathrooms to be able to tile?

 

[Poxeman]

No, 45*70 works fine as well.
https://www.sakervatten.se/FILEARCHIVE/9407E0F7F7F9C1D4013B9462BDC7EF32.pdf

Then you can also build a bathroom without tiling.

 

[catherineb]

No, 45*70 works just fine too.
[link]

And it's possible to build a bathroom without tiling as well

Yes, of course. Yes, it seems to work well with 45x70!

 

[Mikael_L]

Door frame dimensions (thickness) can arguably be considered standardized to a few measurements. (Perhaps they vary by a few mm with some manufacturers, and maybe you can find some that don't follow this at all)

But basically, it goes like this:

68mm frame
Fits a 45 stud in the wall with one layer of board on each side.
Stud + 2 x 13mm gypsum = 71mm, stud + 2x11 mm OSB = 67mm

92 mm frame
Fits a 70 stud and a single layer of board, or a 45 stud and double layers of board.
70 stud + 2x13mm gypsum = 96mm, 45 stud + gypsum + OSB = 93 mm

118mm frame, fits a 70mm stud + two layers of board, or a 95 stud and a single layer of board.

Looking around, you can find 92-96 mm frames, and 68-70mm frames etc.
But a millimeter or two here or there usually doesn’t cause trouble; it just means the siding will tilt slightly.

 

[Jarlsgård]

I am installing OSB now in our bedroom. Since our walls were framed with 45x95 during construction, I don't want to reduce the size where I make changes.

So our walls will be
13mm drywall - 11mm OSB - 45x95 studs with 95mm mineral wool - 11mm OSB - 13mm drywall = 143mm.
Thick as heck but stable enough to withstand a small bomb attack The biggest problem will be door frames. Even the thickest 118mm frames are not enough.

 

[Mikael_L]

Yes, you should probably stick to 45x45 or 45x70 as studs in partition walls if you're using double layers of boards.

I have 45x70 in some load-bearing internal walls (as well as against the bathroom), and 45x45 in the others.

 

[Jarlsgård]

Yes, you should probably stick to 45x45 or 45x70 studs for partition walls if you're using double board layers.

I have 45x70 in some load-bearing interior walls (as well as against the bathroom), and 45x45 in others.

Haha yes.. but if you're not moving walls, it feels silly to replace that nice core wood! The studs currently in place are straighter than the ones you get at the hardware store On the bathroom wall, there will be construction plywood, so that wall will be an additional 4mm thicker

 

[Mikael_L]

Exactly, it feels kind of counterproductive to tear down nice material.

You can buy a regular 96mm frame and then build some reveals around it.


edit: You can get a bit of a stone house feel, with deeply seated frames in thick walls, if that appeals to you.

 

[Jarlsgård]

Exactly, it feels just somewhat counterproductive to tear down nice material.

You can buy a regular 96mm frame, and then you'll need to build some reveals around it.


edit: You can get a bit of a stone house feel, with deeply set frames in thick walls, if that appeals.

The outer walls are stone walls, so it actually gives the same feeling as you mentioned!