I have a very well insulated house, R3.2 batts in ceiling. 2.5 in walls + walls are Hebel panels which adds another R1.1 or something. Problem is I have a stairwell which meets the iron roof and although it has the R3.2 batts between the roof and gyprock ceiling it lets in a lot of heat and heats up the living area. I have measured with a Infrared gun 39 - 40 deg on the stairwell ceiling when the other 2.7 metre conventional ceilings are only 28 deg.
Would it be worth the trouble to lift the iron roof over the stairwell and put foil over the batts or replace the batts with something better? I only have 120mm of space to play with. If I just add foil how much space should I leave between the foil and the iron?
Johnnojack