by JazzQ »
Sat Jun 13, 2020 8:28 am
I am having a single storey extension built and the builder has used 100mm Knuaf Earthwool insulation in the cavity wall instead of 100mm Rockwool insulation as specified in the drawings. I am annoyed at this because I understand rockwool is a better product and has better R value, fire resistant, better sound insulation. Its too late to rectify as the wall has already been built. Approx 26 square meter has been used. How much should I be looking to deduct from the final account now that I have a deficient wall insulation that wont retain heat for longer.
