Nic Posted January 21 Share Posted January 21 Ok if I build a timber framed house and looking to make it as passiv/ airtight as possible without the certificate. what is the best insulation route ? I take it an insulated raft floor but for walls and roof is it better blown cellulose or spray foam it all ? Link to comment Share on other sites More sharing options...
Gone West Posted January 21 Share Posted January 21 5 hours ago, Nic said: I take it an insulated raft floor but for walls and roof is it better blown cellulose or spray foam it all ? You'll get supporters for both types of insulation. I built a PH and used Icynene sprayed foam which gave me an airtightness of 0.47ACH without using any membrames or tapes. The reason I didn't use blown cellulose was because a friend had used it in her house and after a year it had slumped and she used an airtightness membrane but couldn't get below 1.0ACH. There is also blown mineral fibre, which was second on my list. 1 1 Link to comment Share on other sites More sharing options...
IanR Posted January 21 Share Posted January 21 No problems with blown Cellulose here, ~0.1 ACH with no membranes. Can't say I didn't use tapes though, as all windows were taped and all penetration in the external air tight layer (T&G Egger DHF board) were either gasketed or taped. I went with blown cellulose primarily for its air tightness and acoustic qualities. At the time I was making the decision there were also numerous comments going around about PUR/PIR type insulations off-gassing and I wasn't able to quantify any potential risk involved with that, so went with the cellulose and other natural materials as much as possible. 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted January 22 Share Posted January 22 As with all things, none of them are bad, if done right. Personally, from my limited experience, the sound deadening qualities of cellulose would make it my choice. I think there are two ways that this gets installed, dry and wet. I think from memory that the wet method reduces the chance of slumping. There is also the bigger environmental picture. Cellulose is a recycled product, which may, or may not, be environmentally better (mineral wools have a very low embodied energy though). As for the 'off gassing' of polyurethane and phenolic based products, not a problem these days, 50 years ago maybe it was, but we survived the 1960s and 70s. If you are really irrationally worried about it, get rid of your sofa, mattress, car steering wheel, carpet underlay, then move up an isolated mountain, make sure that all combustion technology is banned within 500 km... 1 Link to comment Share on other sites More sharing options...
Conor Posted January 22 Share Posted January 22 Spray foam insualtion has one of the highest embedded carbon levels of any insualtion, cellulose has one of the lowest. Even though you need more of the cellulose, it's still way lower. Never mind one come from trees, and the other comes from an oil refinery. 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted January 22 Share Posted January 22 (edited) 25 minutes ago, Conor said: Never mind one come from trees, and the other comes from an oil refinery And the other comes from plants, possibly. We used to use a vegetable oil derived polyol, worked just the same as the others. If it can be made from oil, it can be made from plants, usually. Edited January 22 by SteamyTea 1 Link to comment Share on other sites More sharing options...
IanR Posted January 22 Share Posted January 22 13 minutes ago, SteamyTea said: If it can be made from oil, it can be made from plants, usually. Is this not at research stage (for use as a thermal insulation product), with work still to do? Is there a commercial product available. I remember reading about blends of veg oil in fossil fuel based PU foams, but then more of the blended product being needed due to the reduced performance of the veg oil. 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted January 22 Share Posted January 22 Just now, IanR said: Is this not at research stage (for use as a thermal insulation product), with work still to do Not really, they have been about for decades. Was back in the 80s I was working with them. I think the very first polyurethanes where bio based, as where the first plastics (called cellulose for a reason) 3 minutes ago, IanR said: Is there a commercial product available No idea. 4 minutes ago, IanR said: blends of veg oil in fossil fuel based PU foams, but then more of the blended product being needed due to the reduced performance of the veg oil. There are so many different blends from secondary re-processor that I can't keep up. It is one of the problems that makes comparisons so difficult. The base may come from 2 or 3 companies i.e. Bayer, but then it has other chemicals added before being shipped out i.e anti-oxidants, plasticisers, lubricants, fillers. 1 Link to comment Share on other sites More sharing options...
IanR Posted January 22 Share Posted January 22 4 minutes ago, SteamyTea said: Not really, they have been about for decades. Was back in the 80s I was working with them. But a bit like EVs from the 1900's they were pushed out by cheaper, higher performing fossil fuel based products. I believe for now, PU based foam thermal insulation products are fossil fuel based, but the industry is having to re-look at alternatives. 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted January 22 Share Posted January 22 1 minute ago, IanR said: I believe for now, PU based foam thermal insulation products are fossil fuel based, but the industry is having to re-look at alternatives. Yes, most probably are, and bio based will be for specialist installations. And there there will be the clash about land usage. We had a spike in grain prices back in the mid 00s because some twat of an oil trader could not work a calculator when working out the consequences of adding 5% bioethanol to gasoline would actually mean. It is going to be either price or legislation that changes the market. But I would still use blown in cellulose. 1 Link to comment Share on other sites More sharing options...
Gone West Posted January 22 Share Posted January 22 1 hour ago, Conor said: Spray foam insualtion has one of the highest embedded carbon levels of any insualtion, cellulose has one of the lowest. Even though you need more of the cellulose, it's still way lower. Never mind one come from trees, and the other comes from an oil refinery. IIRC Icynene is made from oil from the castor oil plant. 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted January 22 Share Posted January 22 10 minutes ago, Gone West said: made from oil from the castor oil plant So is Ricin. Castor Oil Plant has so many uses. 1 Link to comment Share on other sites More sharing options...
Gone West Posted January 22 Share Posted January 22 1 minute ago, SteamyTea said: So is Ricin. Lucky I didn't get a taste for Icynene. 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted January 22 Share Posted January 22 1 minute ago, Gone West said: Lucky I didn't get a taste for Icynene. Just imagine going to see an ancient Aunt and she starts rambling on about chemistry and how her house is insulated with Icynene, then noticing the castor oil plants in her living room, and her Palestinian husband. Or is it just me that has strange Aunts. 1 Link to comment Share on other sites More sharing options...
Gone West Posted January 22 Share Posted January 22 1 minute ago, SteamyTea said: Or is it just me that has strange Aunts. Does it run in the family? 😉 Link to comment Share on other sites More sharing options...
SteamyTea Posted January 22 Share Posted January 22 (edited) 14 minutes ago, Gone West said: Does it run in the family? Depends which side you look at. All the interesting' ones are on the French side. Edited January 22 by SteamyTea Link to comment Share on other sites More sharing options...
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