Insulation

Bungalow with loft conversion - can I place Celotex or Kingspan between battens?

Anonymous user 23/02/2024 - 2.51 PM

HI and please help, I have moved into a bungalow recently with a loft conversion, it has as best I understand a single batten stub wall, with very little insulation if any in some places between the battens, on what I describe as the roof side of the walls, it is like a triangular quadrant that I can access and crawl around the entire loft, the spacing between the rafters of the lower and upper floor has been insulated and boarded over and seems to be doing an adequate job of insulating the downstairs of the bungalow, the underside of the roof tiles is not lagged though, I want to put either Celotex or Kingspan on the upright walls, roof side, the battens are 100mm deep. My long winded question is can I place 100mm Celotex or Kingspan between the battens, up tight to the back of the plasterboard bearing in mind it can breath, or do I need to leave an air gap between the back of the plasterboard and the insulation board? If an air gap is needed as I understand it, I could only fit 50mm insulation board which would reduce the efficiency by half I guess. Many thanks Alec