sonicboom Posted November 30 Author Share Posted November 30 3 hours ago, MikeGrahamT21 said: went up after work and decided to tackle it whilst it’s still cold out, doing work under the eaves is no fun at the best of times! found quite a few bits which I’ve now corrected, where the ceiling joists end was warmer than I’d expected it being, so the wool is clearly doing it’s job, was just too patchy in places, fingers crossed it’ll do the trick anyway. Managed to cut out some excess pipe too from the supply runs, around 3m in total which should help also Its probably useful to understand the purpose of the different types of insulation. Wool type insulations do not stop airflow, they slow it down. This allows for the trapped air to heat up but also for moisture to escape. Its primary use case is in attics because you want moisture that has seeped through to escape otherwise you risk mould growth. Foam type insulations stop airflow completely and convective heat loss is substantially reduced i.e. > 95%, and the primary focus is on conduction/radiation. Pipework should be using some type of foam insulation for this reason. Wool type insulation will help but you are losing heat through conduction, radiation and convection. You just won't get the numbers you want. Link to comment Share on other sites More sharing options...
MikeGrahamT21 Posted November 30 Share Posted November 30 9 hours ago, sonicboom said: Its probably useful to understand the purpose of the different types of insulation. Wool type insulations do not stop airflow, they slow it down. This allows for the trapped air to heat up but also for moisture to escape. Its primary use case is in attics because you want moisture that has seeped through to escape otherwise you risk mould growth. Foam type insulations stop airflow completely and convective heat loss is substantially reduced i.e. > 95%, and the primary focus is on conduction/radiation. Pipework should be using some type of foam insulation for this reason. Wool type insulation will help but you are losing heat through conduction, radiation and convection. You just won't get the numbers you want. I know foam insulation is the gold standard for this type application. had a quick look online and can see climaflex 76mm bore for not much money, but only seems to be 9mm thickness, probably wouldn’t make a worthwhile difference for the immense amount of effort I’d need to put in to install it. hopefully my efforts yesterday which I’m paying for today will work some, there’s no gale force winds up there Link to comment Share on other sites More sharing options...
Marvin Posted November 30 Share Posted November 30 On 29/11/2024 at 10:18, G and J said: Good grief there’s a warning for me. I’ll be running ducts in the loft and had intended to run on top of the first level of fluffy stuff, underneath a couple more. Ok your 100mm of PIR is more insulative than our 100mm of fluff (technical term!) but still, methinks I need to rethinks…. My humble opinion is that you insulate the ..... out of any of the system which is outside the building thermal envelope. I have 400mm of fluffy over the MVHR box and about the same over the ducts... Good luck M Link to comment Share on other sites More sharing options...
JohnMo Posted November 30 Share Posted November 30 Nice discussion but isn't duct supposed have a vapour barrier also? So any type of insulation is fine. Stuff like Climaflex is closed cell so additional vapour barriers are not needed. Link to comment Share on other sites More sharing options...
G and J Posted November 30 Share Posted November 30 1 hour ago, Marvin said: My humble opinion is that you insulate the ..... out of any of the system which is outside the building thermal envelope. I have 400mm of fluffy over the MVHR box and about the same over the ducts... Good luck M If you are M is JohnMo really Q? Link to comment Share on other sites More sharing options...
G and J Posted November 30 Share Posted November 30 1 hour ago, JohnMo said: Nice discussion but isn't duct supposed have a vapour barrier also? So any type of insulation is fine. Stuff like Climaflex is closed cell so additional vapour barriers are not needed. Hmmmm. I’ll have a vcl directly below my bottom level of fluffy but I’m now thinking condensation risk when on summer bypass…. Goodness it boils the brain! Link to comment Share on other sites More sharing options...
JohnMo Posted November 30 Share Posted November 30 1 hour ago, G and J said: when on summer bypass…. Think I would be more concerned about winter, than summer. If summer bypass is on its likely your loft would be unbearably hot. Any condensation would vapourise. 1 Link to comment Share on other sites More sharing options...
G and J Posted November 30 Share Posted November 30 1 hour ago, JohnMo said: Think I would be more concerned about winter, than summer. If summer bypass is on its likely your loft would be unbearably hot. Any condensation would vapourise. And in winter the ducts will be warmer than the loft in our cold loft….. ok, condensation panic over. Link to comment Share on other sites More sharing options...
sonicboom Posted November 30 Author Share Posted November 30 9 hours ago, MikeGrahamT21 said: I know foam insulation is the gold standard for this type application. had a quick look online and can see climaflex 76mm bore for not much money, but only seems to be 9mm thickness, probably wouldn’t make a worthwhile difference for the immense amount of effort I’d need to put in to install it. hopefully my efforts yesterday which I’m paying for today will work some, there’s no gale force winds up there I use https://www.ebay.co.uk/itm/335374071609 Link to comment Share on other sites More sharing options...
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