Frank Kelsall worked on historic buildings in London from 1964 to 1986. In 1986 he moved to English Heritage and acted as Inspector of Historic Buildings for the North West including Manchester and Liverpool.
He retired from English Heritage in 1998, becoming casework adviser to the Ancient Monuments Society and in 1999 established AHP. He has wide experience in building conservation and cites building technology, urban domestic architecture and the history of conservation and town planning among his particular interests. He is a past-president of the Society of Architectural Historians of Great Britain and former chairman of the London Society.