Lambeth · Brixton · Clapham · Streatham · Herne Hill · Norwood
Dormer, L-shaped, hip-to-gable and mansard loft conversions for Lambeth's Victorian terraces and interwar semis. We check conservation area rules, serve party wall notices and handle Building Regulations.
A loft conversion in Lambeth typically costs £45,000–£80,000 for a dormer in 2026 and takes 6–14 weeks on site. Outside conservation areas most rear dormers are Permitted Development. In Clapham Old Town, Brixton, Streatham, Herne Hill and Railton Road you need planning permission.
Last updated 3 October 2026
Lambeth is one of London's best boroughs for loft conversions. Brixton, Stockwell, Herne Hill and Tulse Hill are dominated by Victorian and Edwardian terraces with deep roof voids, while West Norwood and Gipsy Hill add interwar semis that suit hip-to-gable conversions.
The challenge is not the housing stock but the conservation overlay. Clapham Old Town, Brixton, Streatham, Herne Hill and the Railton Road area all carry designations that remove Permitted Development rights for roof alterations. We establish which rules apply to your address first, then tell you plainly what suits your roof.
Outside conservation areas, most rear dormers on Lambeth houses can be built under Permitted Development. Inside them, planning permission is needed and the council looks closely at roofline and materials. The areas to check:
Our Lambeth loft conversion planning guide covers each area in more detail.
On Victorian terraces in Brixton, Stockwell and Herne Hill, a rear dormer is the standard choice, and an L-shaped dormer works where there is a rear outrigger. Where a terrace sits in a conservation area, keep the dormer to the rear slope and expect to apply for planning.
On the interwar semis around West Norwood, Gipsy Hill and Streatham, a hip-to-gable conversion with a rear dormer typically gives the most space and is often Permitted Development outside conservation areas.
Indicative 2026 ranges for Lambeth houses. A free survey gives you an accurate, itemised figure for your roof.
Most Brixton, Stockwell and Herne Hill terraces are rear-dormer territory. Conservation-area schemes in Clapham Old Town, Brixton and Herne Hill carry extra design and planning cost.
Want a personalised range first? Try our free Loft Conversion Cost Calculator.
We measure your roof void, check headroom and confirm whether your street sits in Clapham Old Town, Brixton, Streatham, Herne Hill or the Railton Road area.
Drawings and structural calculations, then a Certificate of Lawfulness, a householder application to Lambeth Council or straight to Building Regulations.
Scaffold licence and skip permits applied for, party wall notices served at least two months ahead, and Building Control inspections handled throughout.
A rear dormer typically takes 6–12 weeks on site under a written JCT contract with staged payments, finishing with a snagging walkthrough.
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It depends on your street. Outside conservation areas, most rear dormers and rooflight conversions on Lambeth houses are Permitted Development within 40 m³ (terraces) or 50 m³ (semi-detached). In Clapham Old Town, Brixton, Streatham, Herne Hill and the Railton Road area you need a planning application, and flats always do. Mansards almost always need one. We check your address at the free survey.
Often yes, but not under Permitted Development. Lambeth Council tends to favour rear dormers that respect the roofline, with traditional materials and proportions, and rarely supports front-facing dormers. Expect to submit drawings, a design statement and the householder fee.
A rear dormer on a Victorian terrace in Brixton, Stockwell or Herne Hill typically falls in the £45,000–£70,000 range in 2026, and an L-shaped dormer on a terrace with a rear outrigger £60,000–£80,000. Conservation-area schemes carry extra design and planning cost, and matching brick or slate can move a project to the top of the range.
Usually a hip-to-gable conversion combined with a rear dormer. It turns the sloping side roof into a vertical gable wall, which gives full-height space across the house. Outside conservation areas it is often Permitted Development, within the 50 m³ limit for semis.
On terraced streets, scaffolding usually goes over the pavement, which normally needs a scaffold licence from the council, and any skip on the highway needs a permit. Party wall notices go to adjoining owners at least two months before structural work starts. We apply for permits and serve notices as part of the programme.
Cost figures are indicative 2026 London ranges for planning purposes, build cost only and excluding VAT, professional fees and fittings. They are not a quotation. Planning and Permitted Development rules depend on your specific address, so always confirm with your local council or a Certificate of Lawfulness.
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