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Insulating Concrete Roof in Outbuilding

Posted: Wed Aug 17, 2016 2:34 pm
by insulateconcreteroof
Hello

I'd appreciate any suggestions - we have an outbuilding with a thick concrete roof; there's no real ventilation, and it gets incredibly hot inside on a sunny day.

Unfortunately I can't insulate it from the outside. Inside, it has very restricted headroom, and there's really only room for an inch or two of insulation.

I realise that in the circus, there's probably not a lot that can be done, but almost any reduction in temperature would be worth having. Knowing nothing about this subject, would foil backed plasterboard be any use, or should I be looking at some kind of foam-based sheeting?

thanks

Re: Insulating Concrete Roof in Outbuilding

Posted: Wed Aug 17, 2016 8:07 pm
by welsh brickie
batten out the ceiling with 50mm x 25mm timber, insulate with 25mm celotex insulation, then use either t&g pine/plasterboard

Re: Insulating Concrete Roof in Outbuilding

Posted: Thu Aug 18, 2016 8:38 am
by insulateconcreteroof
Many thanks, Welsh bricky, looks like that's the way to go.

Whilst I'm here - someone suggested last night that a cheap solution would be to stick polystyrene insulation boards to the ceiling - anyone got any views on whether this option is worth exploring?

Re: Insulating Concrete Roof in Outbuilding

Posted: Sat Aug 27, 2016 8:06 pm
by welsh brickie
polystyrene is a fire hazard and gives off toxic fumes if alight, so it needs to be covered, it also creates condensation. Fibreglass is a cheap option

Re: Insulating Concrete Roof in Outbuilding

Posted: Sat Aug 27, 2016 8:58 pm
by insulateconcreteroof
Many thanks, I'll go with the solution you advised.