Green Building Forum |
Home Books GBEzine Subscription News HelpDesk Your Cart Register |
Welcome to the Green Building Forum. Reading any of the public conversations is free but if you want to join in the discussions then you need to register first to obtain a code for which there is a small charge. Please follow the link on the left. OR:
Logout | ||
© Green Building Press |
||
Comments
PIR is rigid, good thermal insulation, but so rigid it transmits sound too well...:bigsmile:
Good luck...:smile:
In reality though doubling the plasterboard is a smart cheap move....
World
OSB
140mm studs + (kingspan or warmcel or mineral wool batts)
80mm kingspan
OSB
AT membrane
service void
Plasterboard
Skim
Room
Warmcel pros: fast installation, no mess, sound deadening
Warmcel cons: not as good thermally as kingspan
Kingspan (in the 140) pros: thermal value
Kingspan cons: messy, slow to install, little sound deadening
Mineral wool pros: cheap, self fit, less messy than kingspany, acoustic insulating
Mineral wool cons: itchy for a while after, more messy than warmcel
Cost is about the same for KS and WC, and MW is about half the price, so I dare say it's probably the best thing to go for..
Warmcel pros: no mess,
Mineral wool cons: itchy for a while after, more messy than warmcel
A few comments on these -
We're building alongside a friend who's just had Warmcell pumped in. Our build is using SIPs, PUR boards and Rockwool in different places.
Warmcel installation is extremely messy - the stuff seemed to end up everywhere. There's also a fair bit of mess created by cutting the holes to blow it in and work to repair them.
Rockwool isn't anything like as itchy as traditional loft insulation. Using it wasn't nearly as unpleasant as I imagined it would be.
Youtube lied to me!
Anyhoos, it seemt he rockwool is half the price of warmcel and slightly better U in my application so I dare say we'll probably go for that. Already staring down the barrel of a twelve thousand pound bill for insulating, so any saving's a saving!
World
80mm Kingspan (located here it keeps the Timber Frame warm)
OSB
140mm studs + (80mm of kingspan against the OSB and then a 60mm layer of warmcel) The idea is the Kingspan is great for u value and the Warmcel is great for gap sealing, air tightness, sound deading and adds decrement delay.
OSB
AT membrane
service void (am thinking of filling the majority of the unused void with insulation)
Plasterboard
Skim
Room
With the vapour-closed Kingspan on the outside it'd seem sensible to me to put the airtightness layer there as well because then you could just use cheap polythene sheet and it would be well protected from electricians, mice and other vermin in the service void. E.g., between the studs and the outer OSB.
I had similar ideas at one point but chickened out of putting the vapour-closed stuff on the outside - having PUR on the inside and mineral wool on the outside.
I wonder what WUFI would say about the proposed build-up?
We had some blown in through holes or just through missing pieces of board and some just blown in to open studwork with the contractors scrimming up as they went. Holes were easily patched with sticky patches designed for the purpose. Missing boards that the carpenters had pre-cut were nailed in place as we went. And boards went over the contractors' scrim after they finished. All pretty easy.
We used rockwool in various places. It's not too bad to handle but definitely leaves you itchy for a day or two. Pushing it up into the ceiling was the worst part!
I think that rather than a deep timber frame with foam on the outside, I'd be more tempted by a double timber frame.