Browse Forums Building A New House Re: Roof batting? Sydney North West 6Dec 17, 2015 3:31 pm Quote: I wonder if those recommendations include the insulation effect of the plasterboard, as I thought the R2.5 was as high as your could currently get with insulation batts in a standard brick veneer wall. I wouldn't worry about the plasterboard oneJohn. Standard 10mm only has an R-value of 0.06 - hardly worth mentioning. You can also increase the total R-rating for a BV wall by opting for R 2.5HD batts which fit into a standard 90mm timber frame which would boost you up to around R 3.0 for that wall. But as with all things you pay more - $8.59 per sq m for the 2.5HD as opposed to something like $5 per sq m for R 1.5 batts. Or you can go the whole hog like we're doing and go up the next level and get the wall up to just a bit below R 5. Basically an improved BV wall that is a lot better thermally and only another 30mm thicker. http://i1212.photobucket.com/albums/cc455/stewiesno1/Picture%201_zpsvcvonlhp.png Quote: They also have a note to say that the ceiling insulation should be higher than that when the roof upper surface absorbance is greater than 0.4 - which is pretty much anything except a white roof. Yes I agree. For a city like Sydney in the warm/mild temperate zone R 4 is probably all you need especially where we are on the coast. Summer temps around 28-30ºC, winter 10-12ºC min. If I lived further West though where the temps are 5º hotter and frosts in Winter I'd want to boost those walls and ceilings to a higher rating. Stewie |