Question 1

What does a rear extension and open-plan kitchen-diner cost on a 1930s semi in Orpington (BR5 or BR6)?

Accepted Answer

On a typical interwar semi-detached in BR5 or BR6, extending to the rear to create an open-plan kitchen and dining area — including foundations, steelwork, an insulated warm roof or glazed lantern, bifold or sliding doors, and a full kitchen fit-out with integrated appliances — usually falls between £68,000 and £115,000. Heavier clay subsoils in parts of BR5 can push foundation costs upward, and a bespoke kitchen adds materially over a supply-and-fit range. Every cost line — structure, wet trades, joinery, finishes — is presented separately on the day of the site visit.

Question 2

Do Green Belt boundaries around Farnborough and Chelsfield restrict building work on BR6 properties?

Accepted Answer

The southern fringe of BR6 — Farnborough village, Downe Road, and the countryside running toward Cudham — either falls within the Metropolitan Green Belt or sits immediately adjacent to it, where Bromley Council applies strict controls on extensions, new outbuildings, and any work that increases the footprint of an existing dwelling significantly. Even householder applications in these areas face a higher bar than equivalent work in the built-up core of Orpington. PrimeCraft checks Green Belt status and any relevant Article 4 restrictions for every BR6 address at the time of the initial survey, before any design or structural work is committed.

Question 3

Can I build a loft conversion on a detached house in Orpington without a planning application?

Accepted Answer

Most detached and semi-detached houses in BR5 and BR6 can accommodate a rear dormer or roof light loft conversion under permitted development, provided the additional volume stays within the 50 cubic metre allowance for detached properties (40 cubic metres for semi-detached) and the dormer sits back from the front roof slope. Hip-to-gable conversions typically also qualify. Properties in designated conservation areas or subject to an Article 4 direction — a small proportion of Orpington addresses — need a planning application even for modest roofwork. PrimeCraft establishes permitted development eligibility for your specific plot during the site visit, before any structural drawings are commissioned.

Builders inOrpington.

Services we deliver in Orpington

Nearby areas we also cover

Commonquestions, Orpington.

Let's talk through what you're planning.

Builders inOrpington.

Services we deliver in Orpington

Nearby areas we also cover

CommonCommonquestions, Orpington.questions, Orpington.

Let's talk throughLet's talk throughwhat you're planning.what you're planning.

Commonquestions, Orpington.

Let's talk through what you're planning.