How and when do you tell the Council?
Remember that the council is here to give advice. The Building Control Officer responsible for your area will be happy advise you on the procedures to follow.
If you decide upon a loft conversion (or any other type of building work) you need to tell the Local Authority by submitting an application form, giving them either Full plans application or a Building Notice.
If you choose the option of providing a Building Notice then you may need to provide additional information about specific elements of construction where the nature of the work may be complex or unusual (e.g. in the case of a loft conversion, structural engineers calculations are often required for dormer roof and floor structures).
A delay in supplying information can slow the progress of work on site, so we strongly recommend that design solutions are agreed before you start work.