If you are unsure if you need building regulation approval or not, please view do I need building regulation approval.
Once it has been established that the work you intend to do does need building regulation approval, there are 2 ways you can apply.
Should you have already carried out work, which is notifiable, you may be liable for enforcement action. To prevent enforcement, you may submit a retrospective application called a regularisation.
View information on building regulation supplementary information and explanatory notes.