Taking up the floor coverings, lifting floorboards, cutting away plaster, and knocking holes through walls are things to do as infrequently as possible. They are unavoidable when you are dealing with urgent problems such as woodworm, damp, or rot, or carrying out improvements that involve plumbing or electrical work. Once you know what your proposed work will entail, decide whether there's anything else you can afford to do at the same time. If some jobs will have to be done later, leave access to underfloor spaces - screw, rather than nail, floorboards in place, and don't put down fitted floorcoverings until all the work is behind you.