Loft Conversion Builders in London
Add a bedroom, en-suite, or home office without moving house.
All Well Property Services provides professional loft conversions across South East London. I price every project individually after a free site visit, so you get a clear written quote with a week-by-week programme rather than a calculator estimate. All projects include a fixed-price contract, single project manager, and full Building Control sign-off. Call 020 3920 9617 for a free consultation.
What We Offer
Add a bedroom, en-suite, or home office without moving house. We build dormer, L-shaped, hip-to-gable, and mansard loft conversions. One team handles structural design, staircase build, and Building Regulations sign-off.
- ✓Dormer loft conversions
- ✓L-shaped loft conversions
- ✓Hip-to-gable conversions
- ✓Mansard conversions
- ✓En-suite bathroom installation
- ✓Velux and dormer windows
- ✓Staircase design and build
- ✓Building Regulations handled
How I price loft conversions
I quote every job after a free site visit. The price covers materials, labour and a realistic programme, all fixed in writing before we start. No hidden costs, no mid-job surprises.
Book a free site visitWhat Affects the Cost?
- •Roof structure and conversion type
- •En-suite bathroom inclusion (adds from £5,000)
- •Staircase complexity and existing layout
- •Party wall requirements (terraced/semi-detached)
- •Conservation area or planning requirements
Loft conversion specialists in South London
We are loft conversion specialists working across South London. I run every job myself, from the first survey to handover. Since 2020 we have built dormers, hip-to-gables and mansards on the terraces and semis that fill boroughs like Bromley, Beckenham, Lewisham, Dulwich, Crystal Palace, Forest Hill and Balham. If you have searched for a loft conversion company near me, what you want is a builder who knows which conversion suits which roof, not a sales team. One team handles the structural design, the staircase and the Building Regulations sign-off, so you are not chasing separate trades.
A loft conversion in London means knowing the local stock
A loft conversion in London lives or dies on the roof you start with. Victorian terraces here usually take a rear dormer. Edwardian and 1930s semis have hipped roofs that suit a hip-to-gable, and parts of Dulwich, Blackheath and Charlton sit in conservation areas that change what you can build at the front. I read the roof, the head height and the planning position on the first visit, then tell you straight what the loft will take.
Why homeowners choose us as their loft conversion company
Most people call us because they want a bedroom, an en-suite or a home office without the upheaval of moving. We assess head height on the free survey. You need a minimum of 2.2 metres from joist to ridge for the loft to work as habitable space. From that point a single point of contact owns the job, which is the difference between a clean attic conversion and a stalled one.
Types of loft conversion we build
The four main types of loft conversion are dormer, hip-to-gable, mansard and L-shaped, with Velux and rooflight conversions where the existing roof already has the headroom. The right one depends on your roof structure, your head height and whether you sit under permitted development or need planning. Here is how each type works and the kind of house it suits.
Dormer loft conversions
A dormer loft conversion adds a flat-roofed box to the rear slope, which is why it is the most popular choice on terraced houses across Lewisham, Bromley and Greenwich. It creates full standing headroom across most of the floor and usually sits under permitted development, provided it stays within the 40 cubic metre volume limit for a terrace and does not rise above the existing ridge. We build it as a rear dormer so the front roofline is untouched.
Hip-to-gable loft conversions
A hip-to-gable loft conversion extends the sloped side of a hipped roof up to a vertical gable wall, which gains you a large slice of usable floor and head height. It suits the Edwardian and 1930s semis common in Eltham and Beckenham, where the original hipped roof otherwise wastes the corner of the loft. We often pair it with a rear dormer on a semi to open up the whole roof space.
Mansard loft conversions
A mansard loft conversion replaces the entire rear roof slope with a near-vertical wall set at around 72 degrees, which gives you the most headroom and floor area of any conversion type. It almost always needs full planning permission because it changes the roof profile and massing, so I handle the application and the local authority design guidelines as part of the job. This is the option when a standard dormer will not give you the room you need.
Velux and rooflight loft conversions
A Velux loft conversion, also called a rooflight conversion, keeps the existing roof shape and sets the windows flush into the slope. It is the least disruptive build and the lowest cost route, and it works when your loft already has the head height and you do not need to raise the roofline. Because nothing changes outside, a rooflight loft conversion almost always falls under permitted development.
L-shaped loft conversions
An L-shaped loft conversion runs a dormer across the rear and turns it down the side return, which is how you get the most floor space out of a wider Victorian terrace. The extra leg of the L typically lets us fit a separate bedroom and bathroom rather than one open room. It needs the original back addition roof to build off, so I check that the moment I see the property.
Loft conversions with an en-suite
A loft conversion with an en-suite turns a new top-floor bedroom into a proper master suite, and it is the most requested upgrade we add. We plan the soil pipe run and pump position at design stage, because routing waste down from the loft is the part that catches most builders out. The bathroom is fitted and certified by the same team that builds the loft, so there is no handover gap between trades.
Bungalow loft conversions
A bungalow loft conversion is one of the biggest gains you can make on a single-storey home, since the loft can effectively double the footprint into a second floor. The work hinges on the roof structure and whether the existing walls and foundations can carry a new floor, which our structural engineer confirms before we price anything. Adding a staircase into a bungalow layout takes careful planning, and I design that route in from the start.
Loft conversion regulations and standards we build to
Loft conversions carry the highest-stakes Building Regulations of any home project, because you are adding a habitable floor at the top of the house. We handle the fire safety, the structural design and the certification to the relevant codes, and Building Control signs each stage off. None of this is optional. Getting it wrong is what makes a loft conversion fail at inspection.
Fire safety and the protected escape route
Building Regulations Part B requires a protected escape route from the new loft floor down to the front door. That means fire-rated doors to FD30 minimum on every habitable room along the route, mains-wired interlinked smoke alarms on every floor, and 30-minute fire resistance on the staircase walls. Our Building Control inspector signs off the fire safety provisions before the loft is handed over.
Structural design and electrical certification
Our chartered structural engineer calculates the new floor structure, typically I-joists or sawn timber to BS 5268 Part 2 or the equivalent Eurocode 5 EN 1995, with steel beams sized for load and span. Where the existing roof cannot carry the floor loads, we install ridge beams or replacement trusses. NICEIC electrical certification covers all new circuits to BS 7671. Insulation meets the Part L U-value of 0.18 W/m²K for sloping roofs and walls, and the Party Wall Act 1996 applies to nearly every conversion on a terraced or semi-detached property.
How we deliver your loft conversion
One project manager runs your loft conversion from survey to handover on a fixed price and a realistic, weather-aware programme. I keep the trades in the right order and the paperwork ahead of the build, so the job does not stall halfway. The price does not move unless the specification does.
Project management from survey to handover
Your project manager serves party wall notices early in the design stage, because the most common schedule slip is a party wall agreement taking longer than eight weeks. From there we coordinate the structural engineer, book the scaffold and roof-opening work around the weather, and run the trade schedule across plastering, plumbing, electrics, joinery and decoration. You deal with one person, not five.
Fixed-price loft conversion contracts
Our fixed-price contracts cover the lot: structural engineer calculations, party wall surveyor fees, scaffolding licences, FENSA registration for new windows, Building Control fees including the fire safety inspection, and any conservation area applications. We do not open up roof structures in heavy rain, so we assume one day in five may be unworkable for roof-opening work and build that into the programme. Temporary scaffold covers and tarpaulin protect the property through the open-roof phase.
Free tools for planning your project
No email required. Get instant estimates and planning answers before you book a consultation.
Loft Cost Calculator
Estimate the cost of your loft conversion based on type (dormer, mansard, hip-to-gable), intended use, and location in South East London.
Loft PD Volume
Will your loft conversion fit under permitted development? Check the 40 m³ (terraced) or 50 m³ (semi/detached) volume limit, plus the conservation area and highway-facing rules that kill PD entirely.
Best Month
See historic rainfall and temperature for your postcode every month, plus the best window for external work. Live data from the Open-Meteo archive (Met Office and ECMWF).
Listed Check
Check whether your property is a listed building or sits inside a conservation area, and what that means for renovation work. Live data from Planning.data.gov.uk and Historic England.
Related guides
Recent Loft Conversions Projects
Loft Conversions across South East London
What Our Customers Say
“So happy with the work done by Les and Richard!! We bought a house that needed new paint, cracks filled, a new bathroom fan and some mold removal and they did it all. The quality of the work is phenomenal; it looks like a brand new house. We’ll definitely be hiring them for our future projects!”
Brenna Bodine
3 months ago
“So happy with Joel’s work in refurbishing my flat. There was no job too big or small for him and all done to a high standard. I won’t hesitate to use him again!”
Callum Stone
4 months ago
“Joel is 100% reliable, patient, skillful and easy to have around. He repainted my hall, landing and stairs over two floors and made good a disastrous previous plastering problem. I am thrilled with the result and recommend him extremely highly!”
Mel Carter
8 months ago
Accredited & Certified
Our loft conversions specialisms
We build rear and L-shaped dormer loft conversions on Victorian and Edwardian terraces across South London, adding full standing headroom and a proper top-floor room.
Mansard Loft ConversionsA mansard loft conversion rebuilds the rear roof slope to a near-vertical wall at around 70 degrees, which gains the most floor space and headroom of any loft type.
Hip to Gable Loft ConversionsA hip to gable loft conversion squares off the sloping hip end of a roof into a vertical gable wall, gaining real width and head height across the loft.
Velux Loft ConversionsA rooflight loft conversion keeps the existing roof shape and fits skylights into the slope.
Bungalow Loft ConversionsTurning a single-storey bungalow into a two-storey home by building into the roof space, usually with a hip-to-gable and rear dormer that add bedrooms and an en-suite upstairs.
Frequently Asked Questions
- What types of loft conversion are there?
- The four main types of loft conversion are dormer, L-shaped, hip-to-gable, and mansard. A dormer (from £50,000) adds a flat-roofed box to the rear slope and is the most popular choice for terraced houses across Lewisham, Bromley, and Greenwich. An L-shaped dormer (from £60,000) extends across the rear and side of the roof, maximising floor space on Victorian terraces — typically creating 25-35 square metres of usable space. Hip-to-gable (from £60,000) extends the sloped side of a roof to a vertical wall, ideal for semi-detached properties common in areas like Eltham and Beckenham. A mansard conversion (from £70,000) replaces the entire roof slope with a near-vertical wall at 72 degrees, creating maximum headroom but usually requiring planning permission under local authority design guidelines. We assess your roof structure and head height during the free survey — you need a minimum of 2.2 metres from joist to ridge — and recommend the best option for your property type and budget.
- Do I need planning permission for a loft conversion?
- Most dormer and hip-to-gable conversions in London fall under permitted development rights and do not require a planning application, provided they stay within volume limits set by the General Permitted Development Order — 40 cubic metres for terraced houses or 50 cubic metres for detached and semi-detached properties. The dormer must not extend higher than the existing roof ridge, front-facing dormers are not permitted, and external materials should match the existing house. Mansard conversions almost always need full planning permission because they change the overall roof profile and massing. Properties in conservation areas — including parts of Dulwich, Blackheath, and Charlton — face additional restrictions: rear dormers may still be permitted but side-facing dormers and roof alterations visible from the street typically require approval. We handle all planning checks, pre-application enquiries, and formal applications as part of our service, and we apply for a Lawful Development Certificate to give you written proof of compliance.
- Do I need a party wall agreement for a loft conversion?
- If your loft conversion involves any structural work on or within 3 metres of a shared wall with a neighbour — which is the case for most terraced and semi-detached properties in South London — you will need a party wall agreement under the Party Wall etc. Act 1996. You must serve a formal notice on your adjoining neighbour at least two months before structural work begins. If they consent in writing within 14 days, no surveyor is needed and the process costs nothing beyond the notice itself. If they dissent or do not respond within 14 days, both parties must appoint a surveyor (or agree on a single agreed surveyor) to draw up a legally binding Party Wall Award documenting the condition of both properties. The process typically costs from £700 per neighbour depending on surveyor fees in your borough and takes 4-8 weeks. We guide you through every step, prepare the notice documents, and can recommend experienced RICS-accredited party wall surveyors local to your area.
Related Services
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