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From time to time there have been discussions on here about how/whether closed-cell foam insulating -boards ( PIR/PU and extruded-polystyrene ) lose part of their insulation value with time as the blowing-gas leaks out of the closed-cell structure.
This has mainly been about whether these boards are worth the significant premium they have if some of the extra insulation-value leaks away over the first few years,
Whilst looking at the Marmox website in connection with another thread, I noticed that for the first time I have seen, a manufacturer gave an initial insulation value and then a value at 5 years.
http://www.marmox.co.uk/uploads/product_images/47/MarmoxProductBrochureOct09.pdf see bottom of page 2
Thermal conductivity 0.027 watts/mK
Thermal conductivity after 5 years 0.032 watts/mK
So they reckon that their board loses almost 20 % over 5 years which is a fairly significant whack and as far a I have read, this continues until it* ends up at the same value as expanded polystyrene and fibre-wool. ( *talking about closed-cell boards generally, not specifically Marmox )
Obviously there are situations where those materials could not be used, but where they could, do you think it worth paying 3 to 5 times more for something that will disappear relatively quickly ?
This has mainly been about whether these boards are worth the significant premium they have if some of the extra insulation-value leaks away over the first few years,
Whilst looking at the Marmox website in connection with another thread, I noticed that for the first time I have seen, a manufacturer gave an initial insulation value and then a value at 5 years.
http://www.marmox.co.uk/uploads/product_images/47/MarmoxProductBrochureOct09.pdf see bottom of page 2
Thermal conductivity 0.027 watts/mK
Thermal conductivity after 5 years 0.032 watts/mK
So they reckon that their board loses almost 20 % over 5 years which is a fairly significant whack and as far a I have read, this continues until it* ends up at the same value as expanded polystyrene and fibre-wool. ( *talking about closed-cell boards generally, not specifically Marmox )
Obviously there are situations where those materials could not be used, but where they could, do you think it worth paying 3 to 5 times more for something that will disappear relatively quickly ?