I’ve been asked by a friend of my daughter if I could line out an old pre-cast concrete garage to give the inside a clean look so she can use it as an occasional playroom for her children. There will be a stud partition behind the garage door so access to the new "room" will be via the personnel door.

It won’t be a habitable room and she’s not too concerned over the level of insulation but she is very concerned about keeping the cost to a minimum.

So far I’m considering dot & dabbing plasterboard to the concrete walls and putting up a plasterboard ceiling under the apex roof with Rockwool above to at least reduce some of the heat loss through the corrugated roof.

My real concerns are whether dot & dab will be OK on the old concrete but making up an internal frame would obviously considerably increase the work and hence cost.

I could use taper edge boards for the walls to avoid the necessity to skim but what about finishing the ceiling where there would be more joints as I’d need to use smaller boards.

Any advice?

John.

I think the biggest issue is going to be damp...

At a minimum you will want to be fixing decent sized studs to the concrete walls and then maybe fitting an insulation board topped with plasterboard. You need an air gap and ventilation between back of insulation and concrete otherwise your nice plasterboard will look shoddy in no time.

If it's just a cheap nice finish and there isn't the money to do it properly then why not just paint the walls!?

[Edited on 10/5/13 by tegwin]

The concrete walls are not waterproof so if you dot and dab the plasterboard will absorb the damp and fail.

I would build a timber frame inside the garage walls and roof with breathable roofing felt in between the frame and the outer walls and roof, pack insulation in to the frame and then line with plasterboard. Also I would put visqueen on the concrete floor then build a false floor with battens and plywood.

seems like a lot of expense but at least it should last a while.

Yeah, I have thought myself about this, as I wouldnt mind lining out my own steel frame garage, to reduce noise transmission to next door but also add some insulation, for which inslulaion backed plasterboard would be ideal but I just dont think it would last.

As said, I would say your either looking at batterning it out, polythene vapour barrier sheet and then board with plasterboard, inslulation if required.

Else alternatively, given it a good clean (presure washer and detergent?) and paint with a suitable exterior masonary paint and but up some lights. Prehaps a plywood ceiling.


Daniel

My last house had concrete walls which we lined with silver foil insulation straight to the wall then 3x2 timber which the Plasterboards went straight on.

Was ok but wish I had put kingspan in as well.

David

It'd probably be cheaper to have the walls bonded and skimmed than buy timber, boards etc!

Thanks

Aaron

quote:

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Originally posted by Aaron_n_Sim
It'd probably be cheaper to have the walls bonded and skimmed than buy timber, boards etc!

Thanks

Aaron

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No sorry you'd have to blackjack the walls first!

^^^ not a fan here. having a few places that are 100+years old and basements means I have come across damp issues. bitumen coatings blinded with sand, then rendered and platered are relatively short lived and not cheap to do. Plus a PITA when they break down. Batten/boarding with a vapour barrier is my favourite. simple and cheap and dead easy to re-do if needed (but standing up very well thankyou, 12 years of rental to students and no issues)
Dot and dab is hopeless in this situation, the adhesive sucks in water VERY fast and you get nice damp blobs all over the wall.
I would fix treated roof battens to the wall 9proper sized 2x1 from memory) with a strip of DPM between batten and wall. Staple vapour barrier over, and then screw pasterboard. Skim the joints and paint.

What's the budget?

What garden space does she have?

A summer house type shed might be a better solution.

Paint the concrete first... there are Lots of water proof Goops available Xypex is V good to miraculous for this.
Avoid : tar emulsions and chlorinated /elastomerics are crap! These only enrich the Sales types. You have been warned.
Then affix Dow PS insulation board carefully, with a Glue gun :-) This is of ship lapped edges and makes for a "fine' vapor barrier
To that add your gypsum wall board... again with a glue gun.
This materials sequence will not come back to haunt you.. IF.. the concrete walls were not running with water at the outset.

[Edited on 11/5/13 by Bare]