I imagine that this will be the dumbest sounding question but here goes....
I recently bought a house after the first one I was going to buy fell through. I of course stupidly got ahead of myself and pre ordered my insulation (Roxul R20) as it was cheap and I got a bit of a deal.
Turns out however that my new house is 2 x 4 construction and not 2 x 6.
So, here goes my query....
Do I have to really extend my joists by 2 inches or can I trim down the Roxul by 2 inches guessing that the R value would then be about R14?
I know that it would be best to extend them - I'm just looking for a short cut cos I have so much else to do.
I have got to imagine that you know the answer. I think for your own savings on heating bills in the future it would be worth buying a few 2x2 and strapping the walls. It's a small price to pay up front.