If the work involves any new accommodation in the roof space (bedroom, spare bedroom, study, occasional playroom, etc), or any structural alterations (adding or removing joists, installing a roof light if it involves trimming the rafters, etc), then you will need to make a Building Regulations application.
If it involves any alteration to the size or external appearance of the building, then Planning Permission may also be required. Please check with the Development Control section before undertaking any such work.
The following guidance only applies to a loft conversion of no more than two rooms and a floor area of no more than 50m² in an existing one or two storey single-family dwelling house. For advice on any other type of building, please contact the Building Control section. The information in the following pages is for guidance only. Loft Conversions often involve complex construction issues and you are advised to use the services of a qualified architect or surveyor if you are thinking of undertaking such work on your property.