Insulating my eaves

[Twiggy00]

Hi. I have a cold roof so I know I need air flow it I'd like to insulate more without causing condensation.
My trusses aren't very deep so could I put 50mm celotex in between them and leave a gap about 30-40mm between the celotex and felt? Also should I stop the celotex just above the plasterboard ceiling at the bottom to help with the air flow?

 

[tony1851]

Also should I stop the celotex just above the plasterboard ceiling at the bottom to help with the air flow?

Can't quite follow that but it's usual to put the insulant direct on the plasterboard, if that's what you mean.

 

[Twiggy00]

I mean as the celotex comes down the eave spaces then meet the boards

 

[catlad]

If you have eave vents then you need to leave it a bit short to keep the air flow, if you have over fascia vents then you can push it up to the fascia board.

 

[Twiggy00]

Will I get condensation if I do this?

 

[luisdesign]

Will I get condensation if I do this?

Not if you retain an air gap as its purpose is to prevent condensation. Current recommendations are a 50mm clear air gap. You will need to ensure that you can maintain full cross ventilation.

It may be easier to improve insulation of the roof by installing insulated plasterboard to the ceiling.