Hi folks,
Quick question. I have to make this decision quickly, so gut feelings & hunches are fine if it's a hard one to call :)
Through a combination of budget, time & availability, I can only get enough 4" mineral wool at the correct density for the walls.
The walls are as follows:-
3 foot stone wall - Air Gap - Stud work - 2 x 15mm Sound block dry wall with Green Glue.
(My celling is 2 x 15mm drywall - Stud - 200mm mineral wool - 2x15mm drywall hung off isolated frame)
Is it better to have an 4 inch air gap totally filled with mineral wool
Or
6 inch air gap with only 4inch of rockwool slabs jammed into the stud work & a 2'" (sometimes more as the stone work is not plumb) air gap with no insulation.
My gut is telling me to go 6 inch for a softer spring & the mineral wool is essentially air anyway... Hey we don't put wool in window voids after all... But some reasurance from the experts will make me sleep better :shock:
Many thanks for talking the time to read.
Nick
Walls - 6 Inch air gap with 4 Inch wool vs 4 inch filled.
Originally posted at johnlsayers.com, topic 18552.
Hmm, I thought this would be a relatively easy one :?
Maybe not... Anyone fancy having a guess?
Thanks
N
Sorry about the delay in response! I've been on vacations, and it seems like not too may other people are replying to threads right now... :(
Definitely go with the larger air gap, even if you can't fill it entirely with insulation. As long as you have at least 4" of insulation all around, that's fine. The extra depth of the cavity will drive down your MSM resonance greatly, which improves isolation. So go with the biggest air gap you can afford, and put in as much insulation as you an afford as well. But as long as you have 4" of insulation all around, you are good. The insulation does several things, but most importantly it damps internal resonance inside the cavity, and 4" is good enough to do that quite well. - Stuart -Is it better to have an 4 inch air gap totally filled with mineral wool Or 6 inch air gap with only 4inch of rockwool slabs jammed into the stud work & a 2'" (sometimes more as the stone work is not plumb) air gap with no insulation.