Hi All, i've just spent avo running around insulation retailers trying to find a solution to getting an R rating of 3.5 for a cathederal ceiling. i've put in Anticon under a metal roof, and only have 100mm space to fit actual ceiling insulation - i was looking at a polystyrene sheeting, but no-one stocks it down here, one retailer showed me a product called Retroshield (an air-cell product) when i looked at the product sheet it said Thermal Performance Residential Ceiling Heat flow in 3.4 Out 1.5, so what is the R rating of my ceiling if i link anticon with Retro shield? how do u calculate an r rating if in & out r at different values?
cheers Tony