Loft insulation+cross-batten spacing for 18mm T&G Chipbo

[stevebamford]

Hi all,

Good evening to you all.

Plan for loft insulation is to fit 100mm ecowool (b&q stuff) between existing joists.

Then to fit 3x2 cross battens with 60mm Celotex in-between (left by the people that we bought the house from)

Then to board on top with 18mm T&G chipboard

So the questions are:

1) The Celotex is in sheets that are 57cm wide. If I put the cross-battens at this spacing - is that too far apart for the 18mm T&G

2) Do I need an air gap between the top of the Celotex and the bottom of the chipboard - the plan above will give me about 10mm of gap ?

Cheers

Steve