Are the powers of building regulations retrospective?
No, so if works were being carried out to a building and, for example, the existing lintels were discovered to be timber and were in sound condition and would be unaffected by the works or use of the building, you are not required to replace them. Similarly, the building regulations do not require you to provide extraction fans to an existing kitchen if it is not being extended or if the ventilation is unaltered.
