Stud wall from Garage to Utility room...construcion details

[hammerswinger]

Hi,
as part of my ongoing extension I've built a stud wall with a door to separate my garage from the utility room.

The wall is made from 100mm x 50mm timber and insulated between the studs & noggins with 100mm kingspan (Not foil faced).
The utility side of the wall will have 25mm foil faced kingspan over the studs to stop cold bridging and then 12.5mm plasterboard & skim.

The BCO said that the garage side could be sheeted with OSB 3 so that's what I plan to use, but do I need to put a layer of plaster board on before the OSB 3 to give fire protection?

Do I need to have a plastic membrane on the garage side before the OSB 3 goes on?


Thanks.

 

[freddiemercurystwin]

Normally you would use moisture resistant plasterboard to face the garage. If your BCO has said he will be happy with a sheet of OSB instead of PB then one would assume he would be happy with it.

The vapour barrier is the foil on the 25mm Kingspan. Tape the joints with foil tape to seal the gaps and complete the membrane.

No need for any other membranes.

 

[hammerswinger]

Hi,
Thanks for your reply.

I should have mentioned that the stud wall is also supporting a small tiled roof (48 tiles) that's why the OSB has been specified to add strength to the wall, not that it needs it as it would probably hold a battle ship up the way I've built it.

I couldn't remember 100% what the BCO had said about the construction of the wall, hence my question, but just to be on the safe side I rang him this afternoon just to check, he said that it would need a layer of plasterboard on the garage side as well as the OSB, this can go on top or behind the OSB...my choice.
I may put the OSB on top as it's less prone to damage.


Cheers.