Mono pitched roof insulation question

[amsie]

Hi all,

Where would you place insulation when building a mono pitched roof with 6x2 ceiling ties underneath? In other words not a vaulted roof, and additionally is it best practice nowdays to insulation under the joists, such as celotex pl4000??

Sorry if its a dumb question I can't seem to find the detail anyway.

Thanks in advance

Paul

 

[^woody^]

On the ceiling

 

[amsie]

Cheers Woody, let me put it another way.

If I put 100mm celotex inbetween the joists, do I need an additional 50mm below the joists???

Cheers

Paul

 

[freddiemercurystwin]

Just use 270mm Rockwool no need for Celotex.

 

[amsie]

Thanks Freddy,

Do I still need a vapour control barrier?

 

[freddiemercurystwin]

Just use foil backed plasterboard, the foil being the vapour barrier.

 

[^woody^]

On the ceiling

LOL. Note to self, learn the difference between rafters and joists