Which plasterboard?

[Benpointer]

Am I ok to use standard 12.5mm plasterboard for the walls and vaulted ceilings throughout our single-storey timber-framed new build?

 

I was planning to do just, that with a skim, however one of the plasterers we have contacted for quotes has suggested we should use blue acoustic PB throughout.  However the Building Inspector has insisted we fit acoustic insulation to all internal stud walls and the vauled roof make up includes 250mm blown cellulose + 100 PIR, so I feel we will be fine on the sound front. (Plus it's just the two of us most of the time.)

 

Also, I thought I saw somewhere in the building regs that we need to use fire rated PB on the external walls - but I can't find anything about that now I look again.  Our external wall build-up is PB + 25mm service cavity + 50 PIR +140mm frame (with 120mm PIR) + 50 external cavity, then a mixture of timber cladding or render on render-boards.

 

Thanks!

[dave1967]

I dont know about the plasterboard but you will be grateful for them insisting on acoustic insulation.

[nod]

BC shouldn’t be insisting on Aciustic insulation It’s not a requirement to put it in a house Unless your joins to another property ?

 

Strange that quotes would suggest soundblock Is there a noice issue that you haven’t mentioned 

Its normal to use 12.5 wallboard 

30 minutes fire rated 

It should say on your drawing if they are looking for 60 minutes fire rating 

 

[Nickfromwales]

They didn’t insist on it, it’s standard b regs! Acoustic control between habitable rooms is the standard on every job that has stud walls internally. No need for acoustic control on external walls unless it’s to your own advantage. 

 

You only need FR plasterboard if you’re less than 1m from the boundary. If you’ve any steels which are behind the cosmetic PB + skim layer they will give the requisite 30 mins FR for the steel.

 

Acoustic plasterboard on the inside face of all external walls is a good idea if you’re SIPs (timber walls with PIR) as they’re quite acoustically transparent vs masonry / concrete or blown cellulose structures.

 

Odd make up for the roof? Why the combination of insulations?

 

Batten the interior to have 400mm oc’s and 12.5mm everywhere will be fine, but at 600mm oc the ceilings should really be 15mm.

 

Bathrooms need 400mm for the weight per m2, all other rooms are fine at 600mm. 

[Nickfromwales]

26 minutes ago, Benpointer said:

Our external wall build-up is PB + 25mm service cavity + 50 PIR +140mm frame (with 120mm PIR) + 50 external cavity, then a mixture of timber cladding or render on render-boards.

Ah. Defo use acoustic PB on the interior of outside walls, as a lot of nuisance noise gets through these PIR boards. I’d go for 15mm if you’re in a built up area / on a main road. 

[Benpointer]

Thanks for the quick replies.  

 

It's a very quiet rural area but there are houses each side so I'm not sure about acoustic boards - but probably will go for them.

 

The reason for the odd mix in the roof is the rafters are 254mm easi-joists which we're having blown with cellulose, VCL below,  then we will have 100mm PIR below that to give the 0.1 u-value we want.  Also going to run the MVHR duct through channels in that 100mm PIR.  Service cavity below that and then the PB.

 

Might have to go for 15mm on the ceiling then as the joists are 600 and the service cavity battens will need to be below them.