Most loft conversions in Bromley can go ahead without a full planning application, but a surprising number of homes in the borough fall outside those rules. Whether you need permission comes down to your type of house, where it sits and what shape of loft you want. Here is how to work out which side of the line you are on before you spend money on drawings.
Houses usually have permitted development rights, which let you extend into the roof without applying for planning permission, as long as you stay within set limits. If your design fits inside those limits, you do not need to apply to Bromley Council for planning at all.
The main limits for a roof extension are:
Bromley has more than 40 conservation areas, including large parts of Chislehurst, Beckenham, Bromley town centre, Petts Wood, Keston, Downe and Farnborough village. In a conservation area, roof extensions are not permitted development, so any dormer or hip-to-gable change needs a planning application. Rooflights on the front slope can also be restricted.
Some roads in the borough are covered by Article 4 directions, which remove permitted development rights on specific properties, and some older estates had their rights removed by conditions when the houses were first built. Flats and maisonettes have no permitted development rights at all, so a loft conversion above a converted flat always needs planning. Listed buildings need listed building consent as well.
You will also need permission if your design goes over the volume allowance, adds a front dormer, raises the ridge, or uses a full mansard at the rear, which is common on Victorian terraces around Penge and Anerley but rarely fits within permitted development.
Even if your loft falls within permitted development, we recommend applying to Bromley Council for a Lawful Development Certificate. It is not compulsory, but it is written confirmation that the work is lawful, and solicitors will almost always ask for it when you sell. It also protects you if a neighbour complains.
The fee is half the standard householder planning fee, so roughly £250 to £300 at current rates (check the council website for the latest figure). Decisions usually take around eight weeks, similar to a householder planning application, so build that into your timeline.
Planning is only one part of it. Every loft conversion needs Building Regulations approval, whether through Bromley Council's building control team or an approved private inspector. This covers the new floor structure, steel beams, fire safety, the escape route down a protected staircase, insulation and headroom on the stairs.
If you live in a semi or terrace, the Party Wall Act almost certainly applies, because steels usually bear into the shared wall. You must serve notice on your neighbours at least one month before that work starts. If they do not agree, surveyors get involved, which can add cost and a few weeks.
In older properties or those near woodland, as in parts of Chislehurst and Keston, it is worth checking for bats in the roof before work starts, as they are protected and can delay a job if found late.
Not under permitted development, as dormers facing the road are excluded. You would need a full planning application, and Bromley Council tends to resist front dormers unless similar ones already exist on the street.
On an ordinary semi or detached house outside a conservation area, a hip-to-gable conversion usually falls within permitted development provided the total added volume stays within 50 cubic metres. It is still worth getting a Lawful Development Certificate to confirm it.
Bromley Council publishes maps of its conservation areas and Article 4 directions on its website, and you can also ask the planning department directly. Your solicitor's local search from when you bought the house should also show it.