Improvements to office in home of OMB

Buying a new house where the largest room will be used for the business, the director wants to claim for decorating the office, laying laminate floor as it is more practical, and replacing the windows of a large south-facing bay with better insulated ones to reduce daytime temperature extremes. The window are already double-glazed, but not well insulated.

Can he claim any or all? There is no mortgage on the property so rent paid by the company will be minimal.