Brick shed into usable area

[Rexrap]

Hi all

I’m looking to insulate my brick shed to make it more usable for chilling with kid’s watching films etc

I’ve been searching online and there is so much information and a lot of it is contradictory so am somewhat confused

so my plan is currently as follows

empty shed, clean, check for mould, damp and repair any mortar issues

paint on a water proof membrane

attach battens 25mm

attach 25mm polystyrene sheets between battens

cover with plaster board - fill, plaster paint etc

I will also add a faux ceiling either poly tiles or plaster board

add an air vent

would this work? What are the risks?

alternatively I would need to stud it out fully with air gap and add insulation between the studs, but I would lose a lot of room

all and any advise is welcome
Thank you

 

[piglet11]

I improved a single brick skin garage that was damp by putting up one of the breathable roofing membranes, on dabs of Gripfill then battening it to what ever depth I needed (2 x 1 inch battens), infilling between the battens with a rigid foam insulation and overlaying the lot with 9-mm ply. The foam will act as a dampproof layer as well.

Never had damp since.

Bear in mind this was a garage and not meant for habitation, though certainly good enough for a load of expensive tools.
It was a trussed sloping roof, so I insulated under the rafters with Celotex and put up a plasterboard ceiling with smaller sheets of 9-mm plasterboard. An opportunity to practice Artexing as well.

That was one half of a tandem double garage. The other half I did do membrane and CLS studding, insulated and 12.5-mm plasterboard.
Now a nice utility room instead of a grotty unusable garage.