The Council’s decision notice confirming approval states that the building must be built as in the plans in the notice. If any part of what’s built varies from those plans it is unauthorised. Potentially triggering enforcement action. The Council can force such parts to be undone. In extreme, rare cases, enforcement is demolition of entire buildings.
In practice some buildings and extensions are built differently from plans approved. But enforcement does not necessarily occur. Because no-one notifies the difference to the Council (few councils have resources to monitor construction of all approvals). But enforcement is always possible. Especially if neighbours, or the public, do notify the Council. They can recognise differences because the approved drawings are in the public domain. So comparison with what’s built is easy.
Upon notification the Council considers if the variation is “material”. Meaning it could have influenced the decision if known before the decision. Or it may consider the variation “non-material”. Meaning it’s relatively inconsequential. Alternative retrospective secondary applications can then avoid enforcement. There are two types of these depending on material status.
If you want to change the design before, or during, construction submit one or other of those two secondary application types. By, firstly, advise the Council of the change. For it to consider material status. Secondly, depending on whether the change is “non-material” or “material” the Council will tell you which type of secondary application to submit.
If “non-material” the secondary application amends the approval by submission of new drawings. Which are then substituted for the original ones. At the discretion of the planning officer. This type is a Section 96A application.
If “material” the application also requires a drawings submission. But the officer then re-processes them. Including new consultations to neighbours, the public and within the Council. This is a Section 73 application. It leads to a new approval. Or a refusal. If a refusal the original approval remains in place but of course does not contain the change in design.
