Bullwitter
Member
I'm about to install (PollyBatts) in my wall (by removing and replacing the gyprock). My questions is:
Should the wall insulation touch the brick vaneer?
Some batt makers say to use strips of tape to prevent the batts touching the brick BUT Justrite fill the entire cavity, which means that the insulation must touch the inside of the brick vaneer. See. http://www.justrite.com.au/content.php/category/id/23
Advice appreciated.
dymonite69
Member
Brick is porous and some materials can wick the moisture onto the frame or internal linings resulting in rot and mould.
Annette
Member
Its always better to have an air gap - both because of the moisture wicking issue and because it increases R values.
You can also use fishing line or string (two rows strung vertically (tautish) between the studs to keep the batts from touching the brick veneer. Make sure you secure it properly.
You could use rfl foil to line the back of the stud cavity (but not touching the brick veneer). However, if the batts touch the rfl you lose R value - though you do gain 'air tightness' if fitted well. Retro fitting RFL in stud cavities isn't hard - just a bit fidddly.
(BTW - Justrite is retro fitting by drilling holes and pumping in insulation so they can't avoid touching the veneer - but Rockwool is water repellent.)
thats why they are called weepholes
dymonite69
Member
Vapour barrier between insulation and brick wall.
GBD
Member
Just a correction there - Rockwool is normally not water repellent - the stuff used in brick walls is specially treated to make it not wick moisture - ie that way it does not wick moisture from the bricks to the plasterboard. Where does it go - well in time it would move downwards and with warmth it would eventually evaporate.
But in essence - if treated properly it should not soak up much moisture.
So if you're not using the correct stuff - make sure that your insulation is not touching the bricks that would get wet when it rains.
i was being ironic .
enough to make you weep
