900 or 1200 mm drywall?

[Fredrik K80]

I am going to take down old plasterboards and put up new ones. It is framed at cc600. Should I choose 900 or 1200 mm plasterboards?

 

[Magnus E K]

1200 if you don't have extra studs to throw in between every other existing one.

 

[Fredrik K80]

1200 if you don't have extra studs to throw in between every other existing one.

If I put plywood behind. Should they also be 1200?

 

[ETQ]

Had the same dilemma myself 2-3 months ago. It should be added that I live a few floors up without an elevator. I bought 900 and some short studs that I screwed in. I found 900 fairly easy to handle alone when they were going up on the studs. I don't think it would have gone as smoothly with larger ones.

If it had been the ground floor and a helper, 1200 would probably have been a good option

 

[useless]

If I put plywood behind it. Should they also be 1200?

Why plywood? Particleboard or OSB board is sufficient.

 

[Fredrik K80]

Why plywood? Chipboard or OSB board is enough.

Plywood is better 😁

 

[Johan Gunverth]

Install vertical screw-glued 1200 wall particleboard first. It will be vault-like stiff, but requires more work. These can be installed and also glued edge-to-edge. Then you can choose 900 or 1200 drywall and install however you like. It doesn't need to be installed with joints over studs, but avoid matching the joints on the particleboard. The drywall screws only need to be 30-32 mm in this case. Screw 3 rows on 900 board and 4 rows on 1200 board including the edges.
Plywood is expensive. OSB moves (897 resp, 1197) and cannot be glued due to the wax.

 

[RoTe]

First, install vertically glued 1200 wall chipboard. It becomes vault-stiff but requires more work. These can be set and also glued edge-to-edge. Then you can choose 900 or 1200 gypsum board and install however you like. It doesn’t need to be installed with joints over studs, but avoid matching the joints on the chipboard. The drywall screws only need to be 30-32 mm in this case. Screw 3 rows on 900 board and 4 rows on 1200 board including the edges.
Plywood is expensive. OSB moves (897 vs. 1197) and cannot be glued due to the wax.

In this video from Fiskarhedenvillan, they don’t glue the chipboard but install it with a movement allowance of a few mm, and they claim that it’s not sufficient to screw a kitchen in chipboard, for example. So it seems both expensive and unnecessary work in my eyes. Then plywood is probably better in a kitchen, for example, and OSB otherwise in my opinion.

 

[Johan Gunverth]

In this video from Fiskarhedenvillan, they don't glue the chipboard but set it with a movement allowance of a few mm, and they claim that it is not sufficient to screw a kitchen into chipboard, for example. So, it seems both expensive and unnecessary work in my eyes. Then plywood is better in a kitchen, for example, and OSB otherwise in my opinion.

I have personally screw-glued Byggelit's chipboard throughout the house on the advice of two different carpenters I know. They have built using the same method themselves. The installation instructions for the 1200 mm wide boards were that they should also be edge-glued together without movement allowance. The whole idea is to get really stiff walls. The boards were not 1197, which would justify movement allowance like OSB. There were also tongue-and-groove chipboards similar to floor chipboards for wall mounting, but they were unnecessarily expensive. They were also fully glued. For fastenings in the chipboard, you should pre-drill. That's the drawback of chipboard. You can't just nail or screw directly into the material. Then you risk a crater on the inside. In a kitchen, I would have chosen plywood if you can't put in noggings. I did the latter.

Twenty years later, everything is without problems. Nothing has moved. However, it is significantly more work. It's not something a house manufacturer can charge for.

 

[FredrikR]

If I put plywood behind it, should they also be 1200?

If you don't plan to put studs in between, isn't that wise?

What type of room is it and what is the purpose of the plywood behind the plasterboard?

 

[Fredrik K80]

I myself glued and screwed Byggelit's chipboard throughout the entire house on the advice of two different carpenters I know. They have built with the same method themselves. The installation instructions for the 1200 mm wide panels were that they should also be glued edge-to-edge without movement allowance. The whole idea is to have really stiff walls.
The panels were not 1197, which would justify movement allowance like OSB. There were also tongue-and-groove chipboards similar to floorboards for wall mounting, but they were unnecessarily expensive. They were also fully glued.
For fastenings in chipboard, you should pre-drill. That's the downside of chipboard. You can't just nail or screw directly into the material. If you're unlucky, it creates a crater on the inside. In a kitchen, I would have chosen plywood if you can't install noggings. I did the latter.

Now, 20 years later, there are absolutely no problems. Nothing has moved. However, it's considerably more work. It's not something a house manufacturer can charge for.

Does plywood also need pre-drilling?

 

[FredrikR]

No, it is not needed.

 

[Fredrik K80]

Had the same dilemma myself 2-3 months ago. It should be added that I live a few floors up without an elevator. I bought 900 and some short studs that I toenailed in. 900 also went reasonably smoothly to handle alone when they were going up on the studs, I thought. I don't think it would have gone as smoothly with larger ones.

Had it been on the ground floor and with a helper, 1200 would probably have been a good alternative

But say I go with 1200 on the plywood. Should I go with 900 on the drywall then?

 

[FredrikR]

But say I'm using 1200 on plywood. Should I use 900 on the drywall then?

1200 and staggered joints.

Why would you have different sheet sizes, you think?

What kind of room is it, you'll be just fine with OSB. The price difference is greater than the tensile strength difference between OSB and plywood.

 

[ETQ]

But let's say I'm doing 1200 on plywood. Should I do 900 on the plasterboard then?

The only reason I did 900 was because I had to carry them up the stairwell and then install them alone. If you can get large sheets of whatever type you choose underneath, I agree with the above, why would you use different sheet sizes? It only becomes more complicated when, after a few sheets, you end up with a general seam instead...

Either frame it up as needed and use 900 or do 1200 all the way.