Got a job to price. It's a big flat occupied.landlord is selling it but it has failed some heat test .it's got a flat roof .no insulation. I think it's to messey to take down ceilings. I thought counter Barton over existing boards. Then put 37mm insulated PBS. Questions are do u think it's enough insulation. Would it sweat . Wot would you nutters suggest. Cheers.