If your proposed works exceed the permitted development criteria then you will require planning permission.
If the property is a house then you can apply using a ‘householder’ application. We also recommend seeking duty planner advice before applying.
If the property is not a house (for example a flat or a shop) then you would need apply using a ‘full planning permission’ application. We also recommend seeking pre-application advice before applying.
You can submit an online application for these works.