Cavity

[oldgarden]

Thinking of having a 75mm cavity instead of 100mm for an extension wall; space is tight. Does anyone see any issues in doing this. I guess we would use 50mm kingspan and leave 25mm gap. Any issues with this approach?

Cheers

 

[IT Minion]

Thinking of having a 75mm cavity instead of 100mm for an extension wall; space is tight. Does anyone see any issues in doing this. I guess we would use 50mm kingspan and leave 25mm gap. Any issues with this approach?

Cheers

Won't that fall short of the .18 U value standard? You could do full fill instead.

 

[oldgarden]

no idea tbh. wouldnt 50mm insulation be sufficient. think inspector is ok with it. what would be used for full fill?

 

[^woody^]

Best find out first if it meets the u value requirement.

 

[rikaka]

we had to use 90mm in 100mm cavity to meet the u value, with no additional insulation on the walls on the inside. build currently in progress.

 

[oldgarden]

Actually this is a domestic extension, so its not .18. Its .28 I believe and in that respect, the u value can be met.