Xtratherm Fitted to outer wall

[Bigmac74]

Evening all,

My builder has fitted the Xtratherm insulation board in the cavity wall of my new extension. But I noticed that he fitted the board against the outer rather then inner wall i.e. wall consists of breeze blocks then 5mm air gap then 5mm Xtratherm then outer brick.

Most litrature I've seen shows the extratherm attached to the inner block wall - does it make any difference?

As the floor is suspended there are air bricks and I'm concerned the insulation might not be effective (doesnt the air gap get cold due to air entering the wall from the airbricks?

Any help or advice would be much appreciated.

 

[r896neo]

It should be on the inner leaf. You need a good flow of air around your joists so dealing with insulation on a suspended timber floor is a seperate issue.

Air bricks should be sleeved through the cavity.

 

[noseall]

Insulation should be fitted tight against the internal blockwork.

Sounds to me like your brickie has made a boob.