I'm replacing a hearth and Building Regs Part J specify that the
constructional hearth has to have a depth of 500mm from the fireplace.
Unfortunately there is a wooden joist 460mm from the fireplace. If I
was to comply with the regs I would have to remove this part of the
joist. It all seems a bit much for 40mm. What are the consquences of
breaching the regs?