Loft Conversion Builders in Streatham (SW16)
Professional loft conversion builders in Streatham, South London.
Why Choose All Well for Loft Conversions in Streatham?
Streatham's mix of Edwardian terraces and 1930s houses means we see two main types of loft conversion here — dormer conversions on the terraces and hip-to-gable conversions on the semis. Both work well. The terraces have good roof pitch for dormers, and the 1930s semis have generous roof volumes that convert into spacious bedrooms. With Streatham property values rising steadily, a loft conversion that adds a bedroom and en-suite is one of the best investments you can make.
Every project comes with a fixed-price contract, single project manager, and full certification including Building Control sign-off.
Loft Conversions for Streatham Properties
Streatham is known for its edwardian terraces, victorian semis, 1930s houses. Our loft conversions services are tailored to these property types, ensuring results that complement the character of your home.
Postcodes we cover: SW16
Loft Conversions Tip for Streatham Homeowners
The 1930s houses in Streatham Vale and Streatham Common often have concrete interlocking tile roofs rather than slate. When building a dormer or hip-to-gable extension, the new section needs to match the existing tiles — we source matching tiles before starting to avoid a patchwork appearance. Some 1930s properties also have trussed roofs that need structural modification before conversion, which we assess during the free roof survey.
What a Streatham loft conversion typically covers
Three patterns cover most of what we build in SW16. Rear dormer on an Edwardian terrace is the most common Streatham project. The terraces along Streatham Hill, Mitcham Lane, and the streets running off Streatham High Road have cut-roof Edwardian construction with 2.4-2.6 metres of ridge headroom. A rear dormer creates a master bedroom with en-suite within the existing roofline. Cost is £48,000-£72,000 including structure, staircase, en-suite plumbing, electrics, plastering, and decoration. Build time 10-12 weeks. The 40 cubic metre Class B terraced allowance applies under permitted development. Hip-to-gable on a 1930s semi is the second pattern, common around Streatham Common and Streatham Vale. The 1930s semis have hipped roofs that suit hip-to-gable — the sloping side roof is replaced with a vertical gable wall, and a rear dormer creates a full-width master bedroom with en-suite. Cost is £55,000-£82,000 including new gable brickwork matched to the existing facing brick. Build time 12-14 weeks. Many 1930s Streatham roofs use concrete interlocking tiles rather than slate, and we source matching tiles for the new dormer cladding to avoid a patchwork appearance. Semi-detached properties qualify for the 50 cubic metre Class B allowance. L-shaped dormer on wider Edwardian terraces is the third pattern, suitable on the streets where the back addition supports a side dormer alongside the rear projection. Cost is £55,000-£82,000. Build time 12-14 weeks. Party wall agreements with both neighbours apply because the side dormer often crosses the party wall.
Edwardian solid walls, 1930s trussed roofs, and Streatham conservation areas
Three Streatham factors define the structural and planning approach on most loft conversions. Edwardian cut-roof construction (most central Streatham terraces). Built around 1900-1910 with solid 9-inch London stock brick walls and cut-roof construction — individually fitted rafters bearing on the external walls and an internal purlin. The structure can be opened up by adding new floor structure within the existing rafters and a steel ridge beam where the original ridge can't carry the new floor loads. Avoids the £3,000-£5,000 trussed-roof structural premium. 1930s trussed roofs around Streatham Common and Streatham Vale. The 1930s semis often have prefabricated W-frame trussed roofs where every member contributes to structural integrity. Trussed roofs need replacement steelwork (typically a steel ridge beam plus supporting steel beams across the loft floor) installed before any truss can be removed safely. Adds £3,000-£5,000 to typical loft conversion cost and 1-2 weeks to the schedule. We identify the roof type at the survey by checking the existing loft. The replacement also affects the dormer or gable design — the new steelwork bears on padstones on the external walls rather than the internal trusses. Streatham Common, Streatham Hill, and Leigham Court conservation areas. The Streatham Common conservation area covers properties around the Common itself; the Streatham Hill conservation area covers parts of the upper hill streets; the Leigham Court conservation area covers a smaller cluster. Within all three, dormer designs need conservation officer review — front-facing dormers are virtually never approved, rear dormers need subordinate proportions and matching materials. Lambeth Council has Article 4 directions on some streets near the conservation area boundaries that mainly affect front-of-property changes but occasionally remove permitted development rights for rear dormers. We verify the planning status on the Lambeth planning portal at the survey.
Lambeth Council process and project management
Streatham falls under Lambeth Council. Permitted development under Class B covers loft conversions within volume limits — 40 cubic metres for terraced and 50 cubic metres for semi-detached or detached. We submit a Lawful Development Certificate (£103, 6-8 weeks at Lambeth) on permitted development projects for written confirmation, which protects the property at sale time. Within the Streatham Common, Streatham Hill, or Leigham Court conservation areas, full planning at £206 applies and Lambeth typically determines applications in 8-10 weeks. A Streatham loft conversion involves 9-13 trades over 10-16 weeks (longer for trussed-roof properties): structural steel install (with replacement ridge beam and supporting beams on trussed roofs), joist and floor structure, dormer or gable carcassing, brick build-up matched to the existing facing brick, roof cladding matched to the existing covering (concrete interlocking tile or slate), Velux rooflights and FENSA-registered casement windows, insulation (150mm PIR between rafters plus 50mm under to U-value 0.18 W/m²K under Building Regulations Part L), staircase joinery, plastering, NICEIC electrics (BS 7671), en-suite plumbing, decoration. We assign one project manager from survey through handover with photo updates. Fire safety follows Building Regulations Part B — protected escape route with FD30 fire doors on every habitable room along the route, mains-wired interlinked smoke alarms on every floor, 30-minute fire-resistant floor construction. Original ground-floor doors typically need replacement to FD30 standard at £400-£600 per door fitted, included in the contract scope. Stair design follows Building Regulations Part K — 2 metres minimum headroom, 42 degree maximum pitch. Fixed-price contracts cover labour, materials, structural engineer calculations (£700-£1,400 for the design pack including any trussed-roof modification), Building Control fees (£400-£700 at Lambeth), FENSA glazing registration, party wall surveyor coordination, conservation area or Article 4 full planning where applicable, FD30 escape route door upgrades, and the Lawful Development Certificate or planning fee.
Loft Conversions in Streatham: What's Included
Loft Conversions Pricing in Streatham
£45,000 – £80,000
6–10 weeks | Fixed-price contracts | No hidden costs
What Our Customers Say
“All Well managed our project from start to finish. The fixed-price contract meant no surprises, and the result is stunning.”
Verified Customer
Streatham
“Professional team, clear communication throughout. They handled everything including Building Control sign-off.”
Verified Customer
Streatham
Frequently Asked Questions
- How much does a Streatham loft conversion cost?
- Rear dormer on an Edwardian terrace (the most common Streatham project) runs £48,000-£72,000 including structure, staircase, en-suite plumbing, electrics, plastering, and decoration. Hip-to-gable on a 1930s semi runs £55,000-£82,000. L-shaped dormer on wider Edwardian terraces runs £55,000-£82,000. Trussed-roof 1930s properties around Streatham Common and Streatham Vale add £3,000-£5,000 for structural modification. FD30 escape route door upgrades are £400-£600 per door. Party wall surveyor (Agreed Surveyor route) is £900-£1,500. Conservation area or Article 4 full planning adds £206 in fee and 2-4 weeks of lead time. Fixed-price contract before any work starts.
- Edwardian terrace or 1930s semi — which is easier to convert in Streatham?
- Edwardian cut-roof terraces are typically simpler. Three reasons. First, roof structure: Edwardian terraces have cut-roof construction (purlin and rafter) where the existing rafters can be retained and reinforced; 1930s semis often have trussed roofs needing replacement steelwork at £3,000-£5,000 premium. Second, party wall mechanics: 1930s semis only need one party wall agreement (the attached side); Edwardian mid-terraces need both sides, but the additional surveyor fee is offset by the saved trussed-roof premium. Third, planning: most Edwardian terraces sit outside conservation areas and proceed under standard permitted development; some 1930s streets are within Streatham Common or Streatham Hill conservation areas with additional design constraints. The hip-to-gable on a 1930s semi creates more usable floor area than a rear dormer on a terrace, so the right choice depends on space requirement rather than cost alone.
- Why do some Streatham loft conversions need matching concrete tiles?
- Because the existing roof covering on most 1930s Streatham houses is concrete interlocking tile rather than slate. When building a dormer or hip-to-gable, the new roof cladding needs to match the existing tiles to satisfy permitted development materials requirements (Class B requires materials similar in appearance to the existing roof) and conservation area design rules where applicable. Concrete interlocking tile patterns vary by manufacturer and era — Marley, Redland, Sandtoft, and Lafarge each made distinct profiles. We source matching tiles before starting to avoid a patchwork appearance. Where exact matches aren't available, we use the closest equivalent and Lambeth's planning team typically accepts well-matched alternatives. Slate-roof Edwardian terraces in central Streatham use Welsh slate matched to the existing.
- Why hire All Well for a Streatham loft conversion?
- Three reasons. First, accuracy: we know the SW16 stock — Edwardian cut-roof versus 1930s trussed-roof construction, the Streatham Common, Streatham Hill, and Leigham Court conservation areas, the Article 4 directions on some streets, and concrete interlocking tile matching. Second, full accreditation: NICEIC for electrical (BS 7671), FENSA for glazing, Gas Safe registered for boiler relocation, structural engineer calculations included for trussed-roof modification, and Building Control sign-off included on every project. Third, fixed-price contracts: the quote doesn't change unless the specification does. 57 verified Google reviews averaging 4.5/5. Office on Limes Avenue, SE20.
Loft Conversions Near Streatham
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