Also be wary of declaring an entire room to be business related (ie 1/10 of costs as one room is an office and 9 are not), HMRC could in theory insist that 1/10 of any eventual sale proceeds fall outside the Principal Private Residence exemption as they are not residential.
To avoid this only claim 95% of the cost of the room and ensure you have something non-business in there (eg a guitar or a bookcase with fiction books on it). You can then claim the full PPR on sale of the house.














