Builders in Bromley
Bromley's suburban housing stock — predominantly 1930s semis with generous plots — makes it one of South London's most active areas for extensions and garage conversions. Builders in BR1 regularly handle projects that add space to family homes without the conservation constraints found closer to central London.
Bromley's character is defined by its 1930s semi-detached houses, built during the suburban expansion between the wars. These properties have solid brick construction, hipped roofs, and front and rear gardens that offer excellent scope for extension work.
Rear extensions are the bread-and-butter project for Bromley builders. The generous rear gardens mean that single-storey extensions can be substantial — 4 to 6 metres deep — without overwhelming the plot. Most fall under permitted development, and Bromley Council's supplementary planning guidance for extensions is clearly written and straightforward to follow.
Loft conversions in Bromley's semis typically involve a hip-to-gable conversion with a rear dormer, converting the hipped roof into a full gable to maximise headroom and usable space. This is a tried-and-tested approach that works well with the 1930s roof structure, though a structural engineer must confirm the existing timbers can support the conversion.
Garage conversions are particularly popular in Bromley, where many properties have integral or attached garages that are underused. Converting a garage to a home office, playroom, or additional reception room is one of the most cost-effective ways to add usable space, typically costing £10,000–£18,000.
The Rookery conservation area near the town centre and period properties on some of the older roads require more careful treatment, but the majority of Bromley's residential streets are free from conservation restrictions. This makes the planning process more predictable.
Build costs in Bromley are among the more competitive in our coverage area, reflecting the suburban location and good access for deliveries and construction vehicles. Wide driveways and front gardens simplify logistics compared to inner-London terraces with no off-street parking.
Content verified by the South London Trades editorial team — last updated March 2026
TYPICAL COSTS IN BROMLEY
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List your businessA hip-to-gable conversion with a rear dormer is the standard approach for Bromley 1930s semis, converting the hipped side roof into a full gable wall to maximise usable space. This typically creates a large double bedroom with en-suite and costs £34,000–£52,000.
Most single-storey rear extensions up to 4m (semi-detached) or 3m (terraced) fall under permitted development. Bromley Council publishes clear supplementary planning guidance. Properties in the Rookery or Town Centre conservation areas may have additional restrictions.
A garage conversion in Bromley typically costs £10,000–£18,000 depending on the level of finish and whether the garage is integral or detached. This includes insulation, damp-proofing, flooring, electrics, and plastering. It is one of the most cost-effective ways to add a room.