If your property has permitted development rights, you can build a Mansard conversion under a Certificate of Lawfulness. This certificate means that, as long as you build within the council’s guidelines, you do not need to wait for the application to be approved before work commences
If you do not have permitted development rights, you will need to obtain planning permission. With planning permission, you cannot start work until it has been granted. Once a planning application is validated with the council, it should issue a decision after eight weeks.
Here at The Loft Room, we will ascertain exactly which permission is needed and will submit the relevant applications on your behalf to obtain the correct approval.