Roof Insulation

Recycled slates on TLX Gold vapour permeable multifoil sarking overall, over either formaldehyde free glasswool to 350mm, high density glass-fibre batts on Spacetherm or Thermafleece sheep’s wool between built up rafters, underdrawn with plasterboard

There are 3 configurations to the the roof insulation once past the covering:

The remaining floorspace above the attic rooms, in which we have simply topped up the glasswool, down the middle we have used some unwanted rigid insulation to create a crawlway now the insulation is so deep, to get to the solar plumbing. U-value 0.1 W/m2/K

The main slope of the roof has had the rafters built up to accommodate 200mm Thermafleece and is then underdrawn with 10mm plasterboard and skim with no vapour barrier, so fully vapour permeable. U-value 0.143 W/m2/K

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The area under the half gable and dormers where space is at a premium has 100mm Hi-Cav 32 rigid glass wool batts, at the time of installation formaldehyde free was not available but to get the highest insulation value for the smallest thickness this is undrawn with 27mm of Spacetherm on Fermacel board which is vapour impermeable. U-value 0.148 W/m2/K