Insulation How much In Wall Cavity

samthebeat · Post by **samthebeat** » Tue Jan 17, 2006 10:09 pm

Hey I have been away busy building my studio, I will post pics sooner or later. But Im getting to the inteior rooms soon and was wondering how much insulation to put in my cavity, if any.

I want to fill the the cavity (30cm cavity) but wonder if this is worth the money. I intend to put solid fiberglass bats up against the plaster board on each side but dont know what to use in the middle and how much.

Any comments apreciated.

Post by **kendale** » Tue Jan 17, 2006 11:11 pm

Aloha,

Welcome back!

I want to fill the the cavity (30cm cavity) but wonder if this is worth the money. I intend to put solid fiberglass bats up against the plaster board on each side but dont know what to use in the middle and how much.

Here's a recent post: http://johnlsayers.com/phpBB2/viewtopic ... 7755#37755

The attachment might be useful as well.

Looking forward to seeing pics of your progress.

Aloha

samthebeat · Post by **samthebeat** » Tue Jan 17, 2006 11:40 pm

cheers.

I think im gonna do what I said. Im having a 30cm air gap from stud to stud so its atchually more like a 50cm air gap so I reckon in gap Im gonna use some cheap fluffy stuff and use dnser stuff up against the boads.

How much is still a question I will have to figure out. I can buy 10cm thickness of the fluffy stuff and have to layers of it, or I have 3 layers of it so that would 30cm in total, but would 30cm of insulation make it into one big leaf. I dunno. Also I reckon you need sapce for the wir to circulate so the cavity can breath.

thanks again helpfull to know im still on the right track after leaving it alone for a while. I will get those picture posted up, the things a beast man. Ive built this 20X16 building over the summer just gone. Its quite a picture.

Dan Fitzpatrick · Post by **Dan Fitzpatrick** » Wed Jan 18, 2006 5:00 am

you are better off filling the cavity completely. if you want i can go back and find the canadian report that demonstrates this, i have it somewhere ... or you can just trust me

so, it is better to buy more cheaper, less dense insulation (typical fluffy fiberglass insulation works at least as well as denser stuff on low frequencies) so you can afford to fill the space, rather than buy more expensive insulation and only fill part.

the cavity does not need room to breathe or anything, insulation is still considered "airspace" as it lets the air flow through easily.

knightfly · Post by **knightfly** » Wed Jan 18, 2006 7:10 am

Inside a wall, especially THAT thick a wall, go for the cheapest NON-backed breathable insulation you can find that's between .8 and 3 PCF; usually the "fluffy stuff" is cheaper. And Dan's right, a complete fill will improve things. Going HIGHER in density will cost you in low frequency isolation; the lighter weight actually works better at LF... Steve