When works have been carried out without building regulation consent, you will need to apply for building regulations approval retrospectively.
This is known as a Regularisation application.
A 2022-2023 Guidance on Building Regulation Charges.docx[docx] 52KB is payable when you submit the application.
Regularisation applications can only be made if your building work was completed on or after 11 November 1985.
You may have to correct the work or pay a fine if building regulations are not followed.