A bit more advice on extension please

[Tony51]

I have nearly finished the blockwork on my extension now. According to the plans the draughtsman has gone for a vault roof????????
Does any one know of any sites that provide cross sections and examples of this type of roof. Pictures would be very helpfull. thanks in advance

 

[noseall]

a typical example would be say 100mm celotex between the rafters with 50mm over, then counterbatten then lathe and felt as normal.

or

same as above but underdraw the insulation and leave an air gap to the cold side.

celotex

kingspan