The revised edition of Part L comes into effect in June this year.
The U-values for elements of structure have been tightened still further. Walls, for example, have gone from 0.26 to 0.18, which is an incredible reduction of heat loss. Roofs are similarly treated, meaning a lot more Kingspan, which is subject to the law of diminishing returns in terms of payback.
I did a quick calc on a typical wall build-up using brick/100 batts/Celcon and even with 200mm celcon, I couldn't get it down to 0.18, though I might be missing something? Perhaps we are supposed to compensate by festooning the house with PV?
Even so, it seems walls are now going to have to be thicker, which calls into question the viability of 3m extensions under PD.
The U-values for elements of structure have been tightened still further. Walls, for example, have gone from 0.26 to 0.18, which is an incredible reduction of heat loss. Roofs are similarly treated, meaning a lot more Kingspan, which is subject to the law of diminishing returns in terms of payback.
I did a quick calc on a typical wall build-up using brick/100 batts/Celcon and even with 200mm celcon, I couldn't get it down to 0.18, though I might be missing something? Perhaps we are supposed to compensate by festooning the house with PV?
Even so, it seems walls are now going to have to be thicker, which calls into question the viability of 3m extensions under PD.
