Best way to insulate a new 50mm cavity wall

[milese]

Hi,

We're building up the walls on our old conservatory footing which means I'm stuck with a 50mm cavity.

What is the best way to insulate a 50mm cavity? 25mm celotex on the inner leaf with a 25mm air gap?

We will insulate on the inside too.

Thanks

Miles.

 

[John D v2.0]

Full fill wool would be cheaper if it's suitable. Do you have a target u value or just whatever is economical?

 

[milese]

Thanks for reply.

Building regs don't apply but I want the best performance out of what cavity I've got.

It's not a big space so the difference in cost between options isn't really a factor

 

[motorbiking]

If the wall is already there a blown wool fill will work.

 

[milese]

It's currently about 18" but will be built full height with new brick and block work.

 

[cdbe]

A higher performing block will help.

 

[jeds]

Ecotherm EcoCavity full fill PIR is the best insulation value you will get for the cavity. If you want more you will have to line the internal surface with a thermal laminate instead of standard wall board.