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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Building Questions >> Garage conversion https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1537186574 Message started by Glenn Daulton on Sep 17^th, 2018, 1:16pm

Title: Garage conversion
Post by Glenn Daulton on Sep 17^th, 2018, 1:16pm

Hi all.

I am about to have my integral garage converted to a bedroom. 2 internal walls are double skinned and insulated. The external wall is thermalite block internal and brick outer. But the cavity is pretty much non existance(10mm max & no insulation.
What will I need to do to ensure this is insulated enough?

TIA

Glenn

Title: Re: Garage conversion
Post by CWatters on Sep 17^th, 2018, 1:28pm

I suspect your only option is to insulate on the inside. I think I would fit a breather membrane to the wall then either insulation, battens and plasterboard or just insulated plasterboard. Probably at least 50mm of insulation but check what the Building Regs require.

If it's an integral garage how is the wall of the room above it insulated?

You need to think about how wall, ceiling and floor insulation meets up to avoid gaps.

Title: Re: Garage conversion
Post by Glenn Daulton on Sep 17^th, 2018, 11:24pm

Thanks for reply. Yes was thinking it would have to be from the inside with insulated plasterboard. Didn’t know about the breather membrane and wasn’t sure about what thickness.
The wall extends up into its own loft space.

Cheers

Title: Re: Garage conversion
Post by woodsmith on Sep 18^th, 2018, 8:48am

Without a decent cavity between the walls you are likely to have damp bridging the cavity unless the builder has done an impeccable job and both internal faces are perfect which is doubtful. I don't know how much space you can afford to lose, ideally you could do with applying a membrane, battening the wall and fitting foil backed insulation between the battens before fitting a vapour barrier and then plasterboarding. However if you don't have that much space to lose you could use insulated plasterboard. In which case you would dot and dab them to the wall using plasterboard adhesive and then adding some screws to prevent the plasterboard from parting with the wall in the event of a fire. If you are dot and dabbing the plasterboard you can't fit a membrane to the wall use the close cell foam insulated plasterboard and it acts as a vapour barrier so no need to add one of those either.