Insulating single skin garage

[NoviceDiyer]

Hi

I hope you can help please.

I have a long, 'tandem' garage attached to my house. The wall to the left is my house wall so is a cavity wall. The wall to the right is a single skin brick wall (100mm wide). I shall be dividing the garage in half with a stud wall and plan to put insulation between the roof joists (flat roof) with a plasterboard ceiling.

I wish to use the garage as a gym / 'chill out' room so would like to make it a bit warmer. I should add there will be a spa in there also, so a bit of moisture generated from that.

I've tried to find information on the internet and it all seems to contradict itself, so I thought I'd asks the experts on this forum!

Various websites say that I have to put a damp proof membrane against the wall before I attach the insulation, but others say that I do not need this and the insulation board can fix directly to the wall with no damp proof membrane. Some suggest forming a small cavity using battens.

etc, etc ...

Any advice would be greatly appreciated please.

Thanks.

Rob :)

[welsh brickie]

there are various ways to insulate

you can batten out the walls and fit drytherm insulation,vapour barrier,plasterboard,then plaster.
Use insulated plasterboard and fix using drylining adhesive,then plaster.

But you mentioned a spa,the plasterboard would not last so you are best using tounge and groove timber for that.
so you would need to batten out the walls,insulate,then fix the T&G to the battens

[NoviceDiyer]

Thanks for you reply Welsh Brickie.

That make sense - I don't want it all falling off the wall and ceiling in a soggy heap! I assume the timber will need to be treated (tanalised ?) to combat the moisture.

Your advice is much appreciated.

Rob :)

[welsh brickie]

yes its best to be treated you can stain it but no varnish as the wood needs to breathe.

[NoviceDiyer]

Thanks again for your help.

It's always appreciated when somebody who knows what they are doing is willing to offer advice.

Rob