Doubled up 9.5mm PB vs 12.5mm PB

Jul 18, 2016 10 Replies

This is plasterboard ---



Is there any downside to using 2 sheets of 9.5mm on studwork walls (will be skimmed) vs 1 sheet of 12.5mm?



I have relatively little wall to cover compared to ceilings and it would simplify ordering and storing to work with one type.



And I could overlap all joints in the 1st sheet which seems like a bonus.



Just wondered if there were any major downsides?


Can't see any apart from time and cost. Another upside should be improved sound resistance.

Extra thickness seems to be an upside both for fire proofing and sound proofing.

The lighter boards should be easier to handle.

Cost of the extra screws?

Nope - can't immediately see the downside.

Cheers

Dave R

GripIts only work on 9.5-15 mm plasterboard? I know that's almost certainly not major but if you were planning to use dozens of them and only found out later ... :(

I thought everything was done in 12.5 these days? More rigidity in the ceiling and greater fire resistance?

The builders in ours at the moment are certainly using 12.5 on the ceilings.

Cheers - Pete

That's a valid point...

Do you mean the new type:

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Because the old (collarless) type should not be a problem as they'd just push back a little further.

As everything's on 3x2" battens at 450mm centres, the aim is to be able to fix through to the wood - but there may be exceptions.

I'll have to have a think about that...

:)

That they are...

I have just tried a small area for mounting lighting junction boxes on the the attic - what I did was fix 1st sheet with 2 screws then fix right through both sheets with 50mm drywall screws - so longer screws but not really any extra needed (well a couple).

They look like the ones I have. But I see that site includes:

"GripIt Fixings have been designed for use with all types of plasterboard installation: ... Double-thickness plasterboard" ..."

And then goes on with:

"Features & Benefits: Fits 9.5-15 mm plasterboard"

That leaves me with bugger all idea if they mean they work on thickness up to 15mm or up 30mm.

Sorry!

Well, the original type will - just tap them in a bit further.

But I have not seen the new type in the flesh!

It's possible it might not be quite as strong as most of the GripIt will be handing on one of the 2 skins.

Not sure if that will make a lot of difference!

Not really... mostly advantages. Costs a bit more, and some cavity wall fixings may have a harder job, but there are plenty that will still work.

Its standard practice for shop fitters I understand (although they tend to do 2 x 12mm). Give a more rigid wall and better sound isolation.

Cheers John - going with this plan then :)

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