You need to apply for Building Regulation Approval whenever you intend to carry out building work.
The definition of 'building work' is contained within Building Regulations 3.
In general terms, it covers:
Building work did not previously include repair items but over past few years this has changed, in particular in relation to repairs that may affect energy saving. Many repairs and replacements do now require application. If you are in any doubt, please get in touch with the team to discuss it further.
This list of controlled works may not be exhaustive so if in doubt, please contact Building Control.
*A change of use is:
More information can be found on GOV.UK.