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43 replies
70k views
43 replies
What thickness of OSB or plywood behind drywall?
You can use renovation plasterboard to gain a few mm.
I hate bare drywall without anything behind it. If there's no space for both wood board and drywall, I would use MDF; it has a surface that is easy to make look nice. The challenge is to make the seam hold without cracking over time. It should be possible to router or sand down the thickness of the board near the seam by a few mm and splice with a tape.H Horace76c said:I am replacing a small wall section that is about 3600x600 due to a window replacement.
The whole section is more or less hidden behind a radiator.
I'm considering putting OSB on the inside without drywall due to space constraints.
Is it a bad idea to skip the drywall for reasons other than aesthetics?
Drywall provides fire protectionH Horace76c said:Going to replace a small wall section that is about 3600x600 due to a window replacement.
The whole section is more or less hidden behind a radiator.
Considering putting obs on the inside without drywall due to space reasons.
Does it look foolish to skip the drywall for any reason other than the aesthetic?
It might be mentioned in the thread above, but is it OK to choose 10 mm OSB board instead of 11 mm behind the plasterboards? I have 45x45 horizontal (cc 60 cm) screwed into the vertical studs. The reason I'm asking is that the price of lumber has risen a lot recently, and from what I understand, 11 mm OSB is about 100 SEK more expensive than 10 mm OSB. 1 mm difference isn't much, but I want to know before we pull the electrical wires so that the electrical boxes are at the correct "depth".
Double plaster boxes tend to be at the wrong depth even with 11mm OSB, typically 1-2 mm off...
But if you use single plaster boxes with an adjustable ring (which screws to the right level), it works well with 10mm OSB.
For example:
Schneider VP-2 for single plaster or Biltema's with screwable ring (which are actually quite good and very affordable)
https://www.elbutik.se/product.html/apparatdosa--vp2
https://www.biltema.se/bygg/elinstallationer/eldosor/apparatdosa-2000023485
But if you use single plaster boxes with an adjustable ring (which screws to the right level), it works well with 10mm OSB.
For example:
Schneider VP-2 for single plaster or Biltema's with screwable ring (which are actually quite good and very affordable)
https://www.elbutik.se/product.html/apparatdosa--vp2
https://www.biltema.se/bygg/elinstallationer/eldosor/apparatdosa-2000023485
Great tips!Mikael_L said:
Double gypsum boxes often come at a slightly wrong depth even with 11mm OSB, about 1-2 mm off ...
But use single gypsum boxes with an adjustable ring (which screws to the correct level) and it will be fine with 10mm OSB.
For example,
Schneider VP-2 for single gypsum or Biltema's with a screwable ring (which is actually quite good and very affordable)
[link]
[link]
Approximately how much can the ring be screwed out? Is it enough that a green box can be used for double gypsum (25mm)?
It's a bit different.
Biltema’s single drywall boxes probably can’t handle 26mm. I remember in my house, I was a bit undecided about using single or double drywall.
Double drywall sticks out a bit when it's 24mm with osv+drywall.
However, it's easy and quick to cut off 2mm from the box with a sharp knife if you first screw the ring all the way in.
If I chose single drywall boxes instead, there was a problem screwing the ring out far enough. When it reached the wall surface, it was only held by 1-2 thread turns in the box, a bit risky.
This is, of course, with osv+drywall=24mm, so 26mm isn’t good for Biltema’s single drywall box.
On the other hand, VP-2 is a bit more generous with the adjustment space, so there is more overlap.
Their single drywall box with a green ring handles both single and double drywall, and their box with a blue ring handles both double drywall and triple (39mm).
Biltema’s single drywall boxes probably can’t handle 26mm. I remember in my house, I was a bit undecided about using single or double drywall.
Double drywall sticks out a bit when it's 24mm with osv+drywall.
However, it's easy and quick to cut off 2mm from the box with a sharp knife if you first screw the ring all the way in.
If I chose single drywall boxes instead, there was a problem screwing the ring out far enough. When it reached the wall surface, it was only held by 1-2 thread turns in the box, a bit risky.
This is, of course, with osv+drywall=24mm, so 26mm isn’t good for Biltema’s single drywall box.
On the other hand, VP-2 is a bit more generous with the adjustment space, so there is more overlap.
Their single drywall box with a green ring handles both single and double drywall, and their box with a blue ring handles both double drywall and triple (39mm).
Self-builder
· Stockholm
· 10 106 posts
I used ABB boxes and extension rings. The boxes accommodate both single and double gypsum boards. Rings are available in different thicknesses and also thick enough to work in the bathroom with tiles.
mycke_nu said:
Well, I can't say that I have any experience to rely on either, except that I've read that many do it this way and it seems to work here on the walls where I have done so.
Regarding the risk of the screws working their way through the plasterboard due to moisture movements in the OSB, I don't think this risk is very high. The movement can only be a few percent of the board's thickness, i.e., about 0.1-0.2 mm, which is unlikely to cause the screws to go through the paper.
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