Good news for Kent homeowners: most loft conversions can be carried out under Permitted Development (PD) rights without needing full planning permission. Here's what you need to know.
Under PD, you can add up to 40 cubic metres of additional roof space on terraced houses, or 50 cubic metres on detached and semi-detached houses. This is enough for most dormer and Velux conversions.
The key conditions for PD are: the extension must not exceed the highest part of the existing roof, dormer windows must be set back at least 200mm from the original eaves, materials should be similar to the existing house, and no veranda, balcony or raised platform is permitted.
Side-facing windows must be obscure-glazed and non-opening (unless the opening part is more than 1.7m above the floor). This is a common restriction that catches people out.
You will still need Building Regulations approval even without planning permission. This covers structural calculations, fire escape routes, insulation, sound insulation (between the loft and rooms below), and staircase design.
When you DO need planning permission: if your property is in a Conservation Area, is a listed building, has already been extended under PD, or if the proposed dormer faces a highway. Flats also don't benefit from PD rights.
At TEMBOK, we assess every loft at the outset and confirm whether PD applies or whether a planning application is needed. We handle all Building Regulations applications and inspections as part of our service.