Insulating garage breeze block wall

[Siliconslave]

This is what i have found as well, its still better than polystyrene, but arguable not worth the extra for a garage. For the house definitely, i'm going to be using 140mm in the loft.

I used some 120mm in the loft for the 'boarded' section - it's a bit of a pain to work with in some ways - you'll need to cut it to get through the loft hatch and makes a huge mess when you cut it

 

[clv101]

Celotex and the like are all well and good, but what they dont tell you is its only rated for i think around 10 years max, its performance slowly drops to the same level as polystyrene, which is vastly cheaper. In a garage i would be tempted to just use that with some plasterboard over the top.

I'm doing some insulation at the moment and it's not as bad as this. Celotex is CE marked, meaning its stated Lambda value (0.022) have been prematurely aged. See this paper for discussion of the ageing process: utech_2003_aged_thermal_conductivity.pdf

From Celotex FAQ:
"What is the life expectancy of Celotex?
Celotex is expected to remain efficient for the life of the building, and the Lambda values published have been prematurely aged in accordance with British Standards."

Thermal conductivity of polystyrene is 0.033. No way Celotex is as bad as that within a decade.

 

[Dublove]

If you are going with the celotex option or around 50mm in a timber frame, you would be better going for 25 thick boards between batons of 25mm to match. Then a second layer of 25mm foil faced offset over the top, bonded with some foam glue. This will eliminate cold bridging. Then you tape the joints over with foil tape, and screw plasterboard through to batons.

Make sure to mark baton centers on the floor and ceiling before covering!