Loft conversion Croydon work typically proceeds under permitted development — unless Article 4 or an Old Town conservation area applies. GSMS Construction Ltd builds dormer, hip-to-gable and Velux conversions across CR0–CR8, SE25, SW16 and SE19 on a fixed-price contract after a free survey. 2026 guide ranges: Velux £22,000–£38,000; dormer £38,000–£72,000.
- Match the roof to the street: rear dormer on Victorian terraces in Thornton Heath and Addiscombe; hip-to-gable on 1930s Shirley and Sanderstead; a cautious survey on New Addington trussed estate roofs.
- Croydon Council Article 4 on Chatsworth Road and The Waldrons pulls all roof alterations into planning. Old Town conservation areas (Central Croydon, Church Street, Croydon Minster) already exclude Class B roof enlargements.
- Building Regulations apply to every habitable loft, even when planning permission is not required.
- Fixed-price after a free survey. 5-year workmanship guarantee. In-house RC frame for the steels and floor — not a loft-only subcontractor chain.
This is the dedicated loft page for the borough. For general building and commercial work see our construction company in Croydon page. Combining a loft with a rear or wraparound extension? Start with house extensions in London.
Loft conversion Croydon costs in 2026
These are published GSMS Croydon guide ranges, not a phone quote. Your contract is fixed after we measure the roof, stairs, steels and finishes. Planning, structural-engineer and party-wall fees stay extra unless we wrap them into a managed package.
| Type | 2026 guide range | Typical Croydon roof | On-site timeframe |
|---|---|---|---|
| Velux / rooflight | £22,000–£38,000 | Steep Victorian pitch with existing head height (Addiscombe, Thornton Heath) | Shorter end of 8–14 weeks |
| Rear dormer | £38,000–£72,000 | Terraces and many semis across CR0, CR7, SE25 | 8–14 weeks |
| Hip-to-gable (often with a rear dormer) | £45,000–£78,000 | 1930s hipped semis in Shirley, Sanderstead, Purley, Coulsdon | 10–16 weeks |
The dormer band of £38,000–£72,000 is the Central Croydon 2026 table. Addiscombe’s published dormer band is £38,000–£68,000; hip-to-gable there is £45,000–£75,000. We quote inside those Croydon tables, not the older low loft figures on an unrelated extensions article.
What moves you up the band: an en-suite, an L-shaped rear addition, steel to a trussed roof, or conservation materials. Call 07717 790273 or 07453 292996 for a free survey, Monday to Saturday, 9am–5pm.
Roof types by Croydon postcode
Croydon is not one housing stock. A quote written for a Wandsworth terrace or an Ealing Metroland hip will mis-read a New Addington truss. We start with the postcode, then the pitch.
Victorian terraces in Thornton Heath (CR7) and Addiscombe (CR0)
Long 45-degree pitches, rear outriggers, and often an L-plan roof. Head height is usually there. The workhorse is a rear dormer that sits off the eaves, uses matching slate or tile, and leaves the street elevation alone. Where the outrigger allows it, an L-shaped rear form creates a double bedroom plus en-suite without touching the front slope. Velux suits the minority of lofts that already clear standing height and only need light, insulation and a stair. Party wall notices are the rule on these terraces.
1930s hipped roofs in Shirley, Sanderstead (CR2) and Purley / Coulsdon (CR8, CR5)
Inter-war semis here typically have a hipped side roof. A rear dormer on its own leaves a cramped triangle. Hip-to-gable squares that side wall; a rear dormer within the 50 m³ semi/detached volume then makes a full-width room. That is the Croydon 1930s pattern.
Sanderstead Pond, Shirley Park and parts of Purley sit in or next to conservation areas. A street-facing hip-to-gable is often the item that drops you out of permitted development, even when a rear dormer alone would have been fine. We check the designation before we draw the gable.
Estate housing in New Addington (CR0)
Post-war and later estate houses often use fink or fan trusses. There is no room-in-the-roof waiting. Conversion means a new structural floor, steels, and usually a dormer to buy head height. Some New Addington roofs do not pay back a full conversion. We say that on the free survey. Where it does work, the in-house RC frame and formwork team takes the loads properly instead of hoping a loft-only crew can improvise.
SE25, SW16 and SE19
South Norwood, Norbury and Upper Norwood mix Victorian terraces, Edwardian semis and conservation streets (South Norwood, Beulah Hill, Church Road toward Crystal Palace). Rear dormer on the terrace; hip-to-gable on the hipped semi; Velux where the pitch already gives height and the front slope must stay quiet. These postcodes are regular coverage, not a “surrounding areas” line.
Planning permission, Article 4 and Croydon Old Town
National rules sit on the Planning Portal loft conversion page. For a house that is not a flat, not listed and not on designated land, a roof enlargement can be permitted development (Class B) if you stay within 40 m³ on a terrace or 50 m³ on a semi or detached house, do not raise the ridge, do not come out on the principal roof slope fronting a highway, set dormers back from the eaves by 20 cm (hip-to-gable is the exception), match materials, and obscure any side windows.
Croydon then layers local controls. Croydon Council’s own check is the first bookmark we use with you.
Conservation areas — 21 of them, including Old Town
The council currently lists 21 conservation areas, not the higher counts some generic loft blogs still publish. Inside any of them, Class B roof enlargements are not permitted development. A rear dormer or hip-to-gable needs a householder application. A flush rear rooflight can still be the quieter route.
Old Town is the CR0 cluster people miss. Three conservation areas sit inside the Old Town Masterplan: Central Croydon, Church Street, and Croydon Minster (formerly Parish Church). Front-facing boxes, oversized flat-roof dormers and hip-to-gables on prominent street hips are the usual refusals. Subordinate rear work in matching slate, ridge left alone, is the design we take to the council.
Article 4 — Chatsworth Road and The Waldrons
Croydon does not run a borough-wide householder Article 4 on roofs. It runs targeted ones. On Chatsworth Road and The Waldrons, permitted development for all alterations to the roof of a dwellinghouse has been removed (Chatsworth Road direction in force 21 January 2016). That includes work you might assume was “just a Velux”. Other Article 4s (Kenley Aerodrome, Kenley Lane, Mitchley Hill, and the small-HMO direction) have different scopes.
The former Suburban Design Guide (SPD2) was revoked in 2022. Householder schemes are judged against the adopted Local Plan, not that old PDF. On a clean PD scheme we still recommend a Lawful Development Certificate.
Building Regulations — always, even when planning is not
A habitable loft is building work. You need Building Regulations approval for the new floor, altered roof, stair, fire protection, insulation, ventilation and electrics. Planning and Building Regulations are separate.
- Structure. New joists and steels sized to the span. Trussed 1930s and estate roofs are not a few extra ties.
- Fire. A protected escape route, fire-resisting doors and interlinked detection when you add a storey more than 4.5 m above ground — typical on a two-storey Croydon terrace.
- Stairs. Geometry, headroom and a landing that does not steal the best first-floor bedroom without a plan.
- Energy and services. Roof U-values to current Approved Document L; Part P electrics; a proper en-suite if that is in the spec.
Dormer, hip-to-gable and Velux — what we actually build
Three loft types in this borough. We do not sell mansards as a catalogue item, and we do not draw a front dormer on a conservation street to win the survey.
- Dormer. Default on Victorian and Edwardian terraces in CR0, CR7 and SE25. Rear-facing, set off the eaves, matching covering. Aim: a double bedroom and, where width allows, an en-suite.
- Hip-to-gable. Default on 1930s hipped semis in Shirley, Sanderstead, Purley and Coulsdon. Often paired with a rear dormer. Volume and the street-facing hip decide PD versus a full application.
- Velux / rooflight. When the pitch already gives height, or when Chatsworth Road, The Waldrons or an Old Town frontage makes a dormer the wrong fight.
If your roof genuinely needs a mansard, we will say so. We will not invent a fourth product to match a competitor’s menu.
How GSMS prices and builds a Croydon loft
How GSMS delivers a loft conversion in Croydon
- Step 1
Free survey. Head height, rafters or trusses, stair, drainage, neighbours, plus conservation-area and Article 4 status against Croydon Council’s maps.
- Step 2
Route. Permitted development, Lawful Development Certificate, or householder application — in writing before design fees run on.
- Step 3
Fixed-price contract. Itemised steels, dormer or gable, windows, insulation, stair, electrics, plaster, and the en-suite if you want one. VAT number 429761270.
- Step 4
Build. Dedicated project manager. Scaffold, weather the roof, structure, then fit-out. Typical 8–16 weeks on site depending on type.
- Step 5
Handover. Building Control sign-off and a 5-year workmanship guarantee. We do not advertise a 10-year structural warranty we do not give.
GSMS Construction Ltd is registered in Southgate N14 and already publishes Croydon CR0–CR8 as local coverage. Hours: Monday–Saturday, 9am–5pm.
Areas we cover for loft conversions
Central Croydon · Old Town · Addiscombe · Shirley · South Croydon · Sanderstead · Selsdon · Purley · Coulsdon · Kenley · Thornton Heath · Norbury · South Norwood · Upper Norwood · Crystal Palace edge · Woodside · Waddon · Beddington · Addington · New Addington
Postcodes: CR0, CR2, CR5, CR7, CR8, SE25, SW16, SE19.
Frequently asked questions
Often no on an ordinary house outside a conservation area and outside Article 4, if the enlargement stays within Planning Portal Class B limits. Yes if you are in one of Croydon’s 21 conservation areas (including Old Town), on Chatsworth Road or The Waldrons Article 4, listed, a flat, or you want a front dormer, a raised ridge or more volume than 40/50 m³.
Published 2026 GSMS guide ranges: Velux £22,000–£38,000; dormer £38,000–£72,000 (Addiscombe table £38,000–£68,000); hip-to-gable £45,000–£78,000. Your contract is a fixed price after survey.
A Velux / rooflight conversion on a steep pitch that already has head height. If you need full-height floor space, a rear dormer is the honest mid-range spend.
Guide on-site time is 8–14 weeks for a dormer and 10–16 weeks for hip-to-gable, matching the Croydon tables. Velux sits at the quicker end. Planning or party wall can sit in front of that clock.
Sometimes. Trusses mean a new structural floor and steels, so the survey has to prove head height and a stair that works. If the numbers do not work we will say so.
Yes. Old Town, Chatsworth Road, The Waldrons, South Norwood, parts of Sanderstead, Purley and the Crystal Palace edge are in coverage. The design and the application route change. The builder does not.
A 5-year workmanship guarantee on the completed loft. Building Control certification is separate. We do not invent a 10-year structural warranty.
Yes. VAT number 429761270. Quotes say where VAT applies.
Book a free loft survey in Croydon
If you want a loft conversion Croydon homeowners can get through Croydon Council — dormer, hip-to-gable or Velux, fixed-price, on your postcode — call GSMS Construction Ltd.
Call 07717 790273 · 07453 292996 · info@gsmsconstruction.co.uk
Monday–Saturday, 9am–5pm. Free survey. Fixed-price contract. 5-year workmanship guarantee. CR0–CR8, SE25, SW16, SE19. Company details: gsmsconstructionltd.co.uk.