25mm EPS to insulate garage wall?

[Harrier23]

Hi,

I previously posted about insulating my single skin detached garage with 50mm EPS board laid over battons, however I have since decided to go with a 2 x 3 timber frame to give the walls the strength I need.

This will leave me with a 75mm gap to play with. I don't trust that my walls will remain free of moisture all year round, so am keen to have a 25mm air gap between brick and insulation. I would also be covering the EPS with thermal bubble foil insulation which would also act as a vapor barrier but requires a 25mm air gap for the insulation to be effective, leaving me with a 25mm gap for my insulation boards.

Should 25mm EPS, coupled with the bubble foil insulation, be effective enough in retaining heat?

I expect the obvious alternate would be to use PIR boards, but I'm working with a low budget so unfortunately this wouldn't be an option for me.

 

[^woody^]

EPS is crap. OK for packaging maybe. Likewise for bubble foil

However, if you are connecting the heating to main house and the radiator is suitably sized to keep the room warm despite the heat loss, then it may be OK if you are happy to maintain comfort levels by relying on the heating.

Alternatively work out how much the extra heating will cost to keep the room at a comfortable level opposed to the extra cost of good insulation. Also take account of whether the heating will be room controllable or is governed by the main house system - ie will the room cool before the main house system fires up?

 

[Harrier23]

Thanks for the reply.

The garage will only be used whenever I'm in there hitting balls in my golf simulator, so doesn't need to be anything more than just taking the edge off and allowing the room to heat up quicker once it has been insulated and plasterboarded. I would be relying on electric heaters rather than hooking this up to the system in the main house.

It was more a case of would this (along with the loft roll I plan to put in the roof) deliver a good enough result for what I need, or at 25mm EPS and foil insulation am I wasting my time and money?

 

[^woody^]

Insulation does not magically keep a room warm by itself, but will try and retain whatever heat there is. It will make no difference to how fast a room heats up, but how fast it cools down.

You will have to pump more heat into the room to counteract the greater heat loss of thin inefficient insulation.

Your question may well be one of those "how long is a piece of string?" questions. You will certainly be using the heater more, but whether EPS does enough to get the room how you want it is going to be hard to say.