Drywall screw length, is 35mm too long?

[Thorfun]

I am working my way through the Plastering sub-forum and I found this thread

 

 

in it many folk seem to suggest that issues can occur if the plasterboard screws are too long. we have 12.5mm plasterboard and I chose to purchase 35mm drywall screws. should I be worried? we've only done one wall so far so I could easily purchase 25mm screws instead for the rest of the house or is it safe to crack on with the 35mm screws?

Edited July 7, 2023 by Thorfun
typo

[Thorfun]

ok. so in my panic I did a quick Google and found many references to needing to penetrate into the timber by approx 1". so for 12.5mm plasterboard they're saying 38mm screws. e.g.

 

https://www.homebuilding.co.uk/advice/screwing-into-plasterboard

 

I think I've, once again, answered my own question and will just crack on with the 35mm screws. 

 

if anyone thinks I've made a massive boo-boo let me know otherwise I'll assume it's all good.

[Gus Potter]

No 35mm is probably the shortest length for fixing plasterboard if into timber. For plasterboard 9.0mm or 12.5 mm thick I use a min screw length of 38mm.

 

The rule of thumb is that of you are fixing something to timber the embedment length of the screw needs to be 2 x the material thickness you are fixing. Thus a 12.5mm plasterboard needs 3 * 12.5 = 37.5mm.

 

One key thing about fixing plasterboard is you use a bugle head type of screw and screw it in so it lies just under flush of the face of the plasterboard without breaking the paper face. It takes a bit of practice unless you have an auto feed type of screw fixing tool with a depth setting. I would encourage you to do it with an ordinary battery operated screw driver as when you get to corners you may need to use a battery drill anyway.

 

If you go onto the Gyproc website and Utube you can watch videos about how to fix plasterboard correctly. Gyproc tell you how close to the edge of the plasterboard the screws can be and the correct screw spacing for walls and ceilings etc.. There are two edge distances. One is if the paper is left intact at the edge of the board, you get this with tapered edge plaster board, the other when you have cut the plaster board and you have a weak edge, you also get this with square edge plasterboard as the paper does not continue around the edge.

 

Main thing is to read up and then have fun!

 

 

[Gus Potter]

4 minutes ago, Thorfun said:

ok. so in my panic I did a quick Google

Posts overlapped there!

[nod]

Presuming timber 35 for walls 45s for ceilings 

For MF 25s 

[Thorfun]

1 hour ago, nod said:

Presuming timber 35 for walls 45s for ceilings 

For MF 25s 

Thanks. Great info. I already have 25mm for resilient bars and MF ceiling. Will pickup some 45mm for ceilings in to timber. 

[nod]

5 minutes ago, Thorfun said:

Thanks. Great info. I already have 25mm for resilient bars and MF ceiling. Will pickup some 45mm for ceilings in to timber. 

Corse thread for timber Fine for metal 

👍