Loft conversion insulation

[marlb]

Hi, I have an architect comming to do calcs next week but want to get a ball park figure of cost of insulation. Can anyone tell me what thickness I have to achieve in the eaves (100mm rafters and non breathable felt) stud walls and ends of the conversion if using celotex?
I was thinking 50mm air gap, 75mm (25mm battons over rafters) between rafters with 50mm laid over. Then 100mm in stud walls down to floor level. The ends of the loft conversion (brick cavity wall) 100mm between batons laid on wall.

Have I got it about right?

 

[ree]

How about allowing your paid for architect to get it absolutely right?

Celotex do a loft conversion application/calculator on their site. They also, along with Kingspan, do excellent little booklets for DIY'ers or professionals.

 

[tony1851]

Congratulations! You've found an architect who can do calcs!!