A lawful development certificate is a legal document stating the lawfulness of past, present or future development. Whilst a domestic extension or loft conversion may meet all of the planning conditions and be allowable under permitted development, it is advisable (although not compulsory) to make an application for a lawful development certificate. The certificate can be used for planning purposes to confirm any details for further building works or, at the time of sale, to answer queries raised by potential buyers or legal representatives. Shirin Alavi Architects can make this application online with a fee payable to the local authority.