How to fill 150mm cavity

[allthatpebbledash]

What’s the best way to fill a 150mm cavity with insulation?

 

Should I partially fill it and go with 100mm PIR with 50mm gap as is being suggested?

 

Wall build up intention here;

Clayworks plaster or paint

Plasterboard dot dab 

100mm block not specced yet

150mm cavity

100mm block not specced yet 

Render by Baumit I think

 

Theres scope for a wider cavity to be honest but architect is saying going wider would increase costs as majority of ties and other ancillaries or all geared for 150mm cavity’s.

 

I’m not keen on blown EPS beads.

 

Editing to add, the roof is a pitched roof, gable end to end.

 

Intention is a cold roof, with loft roll above joists then boarded over for loft storage.

 

 

Edited 2 hours ago by allthatpebbledash
Roof info

[JohnMo]

Poly beads.

[ADLIan]

Built in mineral wool slabs. 150mm now a standard thickness

[Mr Punter]

Dritherm 32 cavity slabs.

[Iceverge]

Mineral wool batts.

 

Absolutely not put boards.

 

They're next to impossible to install properly in the real world 

[Andeh]

1 hour ago, Mr Punter said:

Dritherm 32 cavity slabs.

This!