A surprisingly large number of people should be informed before you embark on any building project in your home. The local authority project in your home. The local authority has to know because it administrates the building regulations and the town & country planning acts – the main rules governing the building, alterations and use of houses. The lender of the money you used to buy your property should usually be informed, as should the house building and house content insurers. It may also be necessary to tell one or more service authorities – electricity, gas or water – what are you doing. And if you are worried about how it might affect your rates you can get in touch with the Inland Revenue Valuation office (the local authority will do it anyway if you apply for planning permission or Building regulations approval).