Insulating an existing corrugated roof.

[Dee J]

Pondering the feasibility of a cost-conscious conversion of a workshop building to residential, and one of the key points would be if we could retain the existing roofing. So its a fairly conventional pitched roof with timber A-frames and purlins covered in cement fibre corrugated sheets. It was re-sheeted recently enough for it not to be asbestos. Currently its insulated in about 75mm of kingspan and clad in 9mm ply.... ok for a workshop, but insufficient for residential. Also we'd need to integrate some proper insulated skylights to replace some sections of transparent sheeting. Any advice?

Thanks.

[scottishjohn]

first stop is building control regs to see what is minimum insulation value on roof and walls ,and is there a dpc in floor+ walls  of  the building 

any conversion you make will have to comply with CURRENT requirements for a habitable dwelling  -as it is a change of use ,you may even find that the roof structure will not pass for a dwelling  if it was an agricultural building to start with .