Kingspan for loft flooring?

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The use of Quinn-lite probably explains it - they have lower conductivity than standard block.
 
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:)

I actually misunderstood. But in general you're saying that 50mm Quinn rigid board foam is not better than 100mm rockwool. My builder (friend) believes it is better and covered the higher cost, mainly because we were taking our time on brick selection and he needed to crack on so didn't put rockwool.

For lofts room and single storey he has / will use 100mm of the same rigid board as part of a warm deck.
 
It is not twice as better in "laboratory" conductivity terms. The lambda of Rockwool is 0.037 W/mK, the lambda of quinn-therm is 0.022.

The lambda of generic mineral wool can be up to 0.044, so that would mean Quinn-therm would be exactly twice as better if you happened to choose one of those products.

But as I said it depends what you mean by "better" - conductivity is not the only question. Insulation is very sensitive to quality of installation, so a product that is easier to install might be able to achieve the desired result, whereas another product may not.

If you have room I would maximise insulation everywhere. It's a lot more expensive to add later.
 
Can someone update me on the current cavity wall requirements.

I thought that it was still a cavity of 50 mm filled with 50 mm of insulation?

The earlier reference was for a cavity of 100 mm but only half filled with 50 mm of insulation!

Tony
 
Can someone update me on the current cavity wall requirements.

I thought that it was still a cavity of 50 mm filled with 50 mm of insulation?

The earlier reference was for a cavity of 100 mm but only half filled with 50 mm of insulation!

Tony
Yes you cannot completely fill the cavity. Need to leave room for air due to moisture etc. had this confirmed by my building regs inspector.
 
No, assuming you are not on an exposed site you can do full fill, with batts anyway. In fact there's some good evidence that it works better, because otherwise you get convection in the cavity (especially with an insulant as shallow as 50mm).

Remember lots of BR inspectors sometime need convincing or a friendly pointer to the regulations.

http://www.planningportal.gov.uk/bu...ments9/acd#MasonryCavityWallInsulationDetails

I would prefer 100mm full fill batts to 50mm PIR/PUR (assuming a non-exposed site again).

Actually I'd prefer about 300mm batts but...
 
Isn't the difference for an exposed site because of the fear of moisture penetrating the outer skin and getting through to the inner skin?

Tony
 
Yes, wicking through the insulation (also rendering the insulation useless, as well as the damp effects).
 

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