House Extensions
in
Lewisham
Building extensions across the London Borough of Lewisham — from the Victorian terraces of Brockley, Hither Green, and Honor Oak to the Edwardian suburbs of Lee and Forest Hill, and the distinctive conservation areas of Telegraph Hill. Local knowledge, end-to-end management, honest pricing.
Proudly Serving Lewisham
Planning to Handover
Free Site Consultations
Victorian Terraces.
Real Potential.
The London Borough of Lewisham is one of the most diverse housing boroughs in South London — stretching from the densely Victorian streets of New Cross and Brockley in the north, through the gentrified terraces of Honor Oak and Crofton Park, to the greener, more suburban character of Hither Green, Lee, and Forest Hill in the south. The common thread is the Victorian and Edwardian terrace — and almost every one of them has the potential to be significantly improved by a well-designed extension.
At Kelmend Construction, our house extensions service covers all of Lewisham and we know the borough well. The narrow side returns on Brockley's terraces, the wider plots in Hither Green and Lee, the significant conservation area requirements on Telegraph Hill, the planning preferences of Lewisham Council — these are details that matter on every project and that we understand from working across the borough for years.
We Know
Your Property
Victorian Terraces
The Victorian terraces of Brockley, New Cross, and Crofton Park are among the most sought-after in South East London — long, relatively narrow plots with small rear kitchens that desperately want opening up. Side return extensions and wraparounds are the most transformative projects we carry out in these streets — turning dark, cramped Victorian kitchens into wide, light-filled family spaces. Brockley's conservation area applies to many of these streets.
Edwardian Semis & Terraces
Honor Oak and Forest Hill contain an excellent mix of Edwardian terraced and semi-detached properties — typically with slightly more generous proportions than their Victorian counterparts and rear gardens that work well for rear extensions. Forest Hill's elevated position means many of these properties have excellent light, which a rear extension can amplify dramatically. The Honor Oak conservation area covers parts of the area.
Telegraph Hill Terraces
Telegraph Hill is one of the most architecturally distinctive conservation areas in the London Borough of Lewisham — a grid of late Victorian terraces laid out on a steep hill, many of which have been carefully restored by their owners. Extensions here are possible but require design sensitivity, sympathetic materials, and thorough engagement with Lewisham Council. The return on investment for a well-executed extension in this area is consistently strong.
Edwardian Suburb Semis
The Edwardian suburbs of Hither Green, Lee, and Ladywell contain some of the most spacious and well-built housing in Lewisham — larger semis and short terraces with more generous plots than the inner-borough Victorian stock. These properties are ideal for double storey rear extensions, side extensions, and wraparounds. Hither Green has its own conservation area covering some of the most distinctive streets.
1930s Suburban Semis
The outer Lewisham suburbs of Grove Park, Bellingham, and Downham are predominantly 1930s semi-detached housing — built by the London County Council and private developers to house families moving out of inner London. These properties typically offer the most straightforward extension projects in the borough with generous permitted development scope and more predictable construction conditions than the Victorian terrace stock.
Mixed Victorian & Post-War
Catford and the Sydenham border contain a mix of Victorian terraced streets, post-war estates, and more recent housing. The variety means that planning and construction conditions vary significantly by street and even by property. We assess each address individually — the permitted development scope, conservation area constraints, and construction approach that apply to one Catford street can be entirely different from the next.
Types of
Extension
Rear Extension
The most commonly built extension across Lewisham's Victorian and Edwardian stock — extends the ground floor into the rear garden to create open-plan kitchen and living space. Outside conservation areas, many of Lewisham's terraced properties qualify for permitted development for single-storey rear extensions, though we always verify this for the specific address first.
Double Storey Extension
Adds rooms on both floors — typically a larger kitchen below and an extra bedroom or bathroom above. Particularly popular on the larger Edwardian semis of Hither Green, Lee, and Honor Oak where the plot supports it. Always requires planning permission. Lewisham Council assesses double storey extensions carefully against the character of the surrounding streetscape.
Side Return Extension
The most transformative project on a Victorian terrace. Fills in the narrow alleyway running down the side of the property to dramatically widen the kitchen or ground floor. In Brockley and Crofton Park, where the typical Victorian terrace has a cramped kitchen at the rear, a side return extension completely changes how the ground floor functions.
Wraparound Extension
Combines a rear extension and side return into a single L-shaped build — the most expansive single-storey option for terraced properties. Very popular across Lewisham's Victorian terrace stock in Brockley, Honor Oak, and Forest Hill. Creates dramatic open-plan spaces out of what were dark, disconnected Victorian rear rooms. Requires planning permission where conservation areas apply.
Side Extension
Builds outward into the side passage of a semi-detached property — commonly done on Lewisham's Edwardian and 1930s semis in Hither Green, Lee, and Grove Park. Can add a utility room, downstairs WC, home office, or enlarge the existing kitchen footprint. Outside conservation areas, many of these fall under permitted development.
Garden Room Extension
A full-build extension with large glazed doors, quality insulation, and integrated heating. Particularly effective on the larger plots in Hither Green, Lee, and Forest Hill where rear gardens allow for a generous footprint. Not a garden shed — built to the same structural and insulation standard as the main house.
What You Need
to Know
Lewisham is administered by the London Borough of Lewisham — a different planning authority from the neighbouring Royal Borough of Greenwich or the London Borough of Bromley. Here's what most affects homeowners across the borough.
Brockley Conservation Area
Brockley is a significant conservation area covering a large portion of the north of the borough. Many of the Victorian terraces in Brockley, Crofton Park, and Honor Oak Park fall within it. Design quality and material choices are subject to close review, and Article 4 directions remove some permitted development rights in the core area.
Telegraph Hill
Telegraph Hill is one of Lewisham's most architecturally important conservation areas — a grid of late Victorian terraces with a distinct character that the council actively protects. Extensions here are possible but require sympathetic design and materials consistent with the Victorian character of the streetscape.
Permitted Development
Outside conservation areas and Article 4 zones, many Lewisham properties qualify for permitted development for single-storey rear extensions. The outer borough areas — Hither Green, Lee, Grove Park, Bellingham — typically have more straightforward permitted development scope than the inner Victorian terrace areas.
Multiple Conservation Areas
Lewisham has conservation areas beyond Brockley and Telegraph Hill — including Hither Green, Honor Oak Park, Ladywell, Forest Hill, and others. We check the specific address before every project to identify which, if any, apply and what restrictions are in force.
Typical Approval Timelines
Lewisham Council typically processes household planning applications within 8 weeks of validation. Applications involving conservation areas, Article 4 directions, or neighbouring objections can take longer. We factor realistic timelines into every programme from the start.
Party Wall & Neighbours
Almost all extensions in Lewisham's terrace stock involve party wall considerations. We flag this at the consultation stage so notices can be served early and party wall agreements reached well before the build start date.
Lewisham's
Conservation Areas
Lewisham has a substantial number of conservation areas spread across the borough. If your property falls within one, additional design considerations apply. We've worked across all of the following:
Conservation area boundaries in Lewisham are not always obvious from the street — a row of houses can span two or three different designations. The only way to be certain is to check your specific address against the council's current conservation area maps, which we do at the consultation stage for every project.
Why Lewisham
Homeowners Choose Us
Victorian Terrace Specialists
The Victorian terrace is Lewisham's dominant property type — and it has specific structural characteristics, construction quirks, and planning considerations. Suspended timber ground floors, lime mortar brickwork, variable soil conditions, and party wall sensitivities. We've worked across hundreds of Victorian terrace extensions and know what to look for before we start.
Conservation Area Experience
Brockley, Telegraph Hill, Honor Oak Park — we've delivered extensions in all of them. Conservation area work requires a different approach to materials, proportions, and council engagement. We know what Lewisham Council expects and what gets approved.
Family-Run, Directly Accountable
You deal with us throughout — not a sales team, not a distant project manager. On a borough where many homeowners have invested significantly in their properties, that direct accountability matters.
Itemised, Honest Quotes
Full line-item quotes with no hidden costs or vague allowances. Any changes are costed in writing before we proceed. The standard you should expect — but that many builders in this borough don't deliver.
Planning Handled
We advise on planning routes, work with architects familiar with Lewisham Council, and manage building control throughout. You won't be chasing the council or coordinating consultants yourself.
Quality That Reflects the Investment
Lewisham's Victorian and Edwardian properties have been significantly invested in by their owners over recent years. A well-built extension reflects and extends that investment. A poor one detracts from it. We build to the standard the properties deserve.
Our Extension
Process in Lewisham
Free Consultation & Site Visit
We come to your Lewisham property, walk the space, and discuss what you want to achieve. We give you an honest assessment of what's feasible, what planning route applies for your specific address — including conservation area and Article 4 constraints — and the realistic budget you're looking at.
Design & Planning
We work with your architect — or recommend one experienced with Lewisham Council — to develop drawings. We advise on the planning route, submit any required applications, and manage party wall notices. For conservation area properties, we engage early with the council's planning team to understand design expectations before finalising drawings.
Detailed Quote & Contract
Once planning is approved and drawings finalised, we produce a fully itemised quote. Scope, timeline, stage payments, and how variations are handled — all clearly set out in writing before any work begins.
The Build
Work starts on the agreed date. We manage groundworks, structure, trades, and materials. Regular photo updates and direct access to us throughout. Site secured and cleaned every day — essential on Lewisham's tightly-packed Victorian terrace streets where neighbours are close and the street is watched.
Finishing & Fit-Out
Plastering, flooring, electrics, plumbing, and decoration coordinated as a single programme. The finish on a Lewisham Victorian terrace has to be right — the investment that's gone into these properties demands a result that matches.
Handover & Sign-Off
London Borough of Lewisham building control sign-off obtained. Full snagging walkthrough with you. We don't close the job until you're satisfied — and we remain on the end of the phone if anything comes up afterwards.
Covering the
Whole Borough
We carry out house extensions across the London Borough of Lewisham. Our core areas include:
Lewisham Extension
FAQs
How much does an extension cost in Lewisham?
A single storey rear extension in Lewisham typically costs between £1,500 and £2,200 per square metre, depending on size, specification, and finish. A 20m² kitchen extension might range from £30,000 to £50,000 fully finished. Victorian terrace extensions in Brockley and Crofton Park sometimes carry slightly higher costs due to specific structural conditions — suspended timber floors, variable foundations, and party wall requirements that add complexity. We'll give you an accurate figure after visiting your property.
Do I need planning permission for an extension in Lewisham?
Not always. Many single storey rear extensions on Lewisham's Victorian and Edwardian properties fall under permitted development — particularly in Hither Green, Lee, and Grove Park outside the core conservation areas. However, if your property is in the Brockley conservation area, Telegraph Hill conservation area, or any of Lewisham's other designated areas, planning permission is required and design quality is closely reviewed. We check your specific address at the start of every project.
What is the Telegraph Hill conservation area?
Telegraph Hill is one of Lewisham's most significant conservation areas — a grid of late Victorian terraces laid out on a steep hill between New Cross and Honor Oak. The area is characterised by its consistent architectural style, distinctive yellow-stock brick terraces, and views from the hilltop. Lewisham Council actively protects the character of the area, and extensions here must be sympathetically designed in materials and proportions consistent with the Victorian terraces. We've delivered extensions in Telegraph Hill and understand what the council expects.
What is the Brockley conservation area?
The Brockley conservation area is one of the largest in the London Borough of Lewisham, covering a significant portion of the Victorian terrace streets between Crofton Park and New Cross. Properties within it face additional design requirements for any external alterations, and Article 4 directions remove some permitted development rights. If your property is in Brockley SE4, it's worth checking whether it falls within the conservation area boundary before designing your extension — we'll confirm this at the consultation.
How long does Lewisham Council take to approve planning applications?
The London Borough of Lewisham typically processes household planning applications within 8 weeks of validation. Applications involving conservation areas, Article 4 directions, or neighbouring objections can take longer. We build realistic timelines into your programme from the start so that planning delays don't come as a surprise.
Will an extension add value to my Lewisham home?
In most cases, significantly. Lewisham's Victorian terrace market — particularly in Brockley, Honor Oak, Hither Green, and Telegraph Hill — has seen substantial value growth over the past decade, and a well-built extension can add 10–20% to a property's value. The return is strongest where the extension meaningfully improves the function of the house — opening up a cramped Victorian kitchen into an open-plan family space is one of the highest-return projects you can undertake. Build quality matters enormously, particularly in conservation areas.
Can I stay in my Lewisham home during the extension?
In most cases, yes — and most of our Lewisham clients do. We plan the work carefully to minimise disruption, particularly during the breakthrough from the existing kitchen into the new extension. We seal off dust, protect flooring and furnishings, and always leave the site clean and secure at the end of the day. On tightly-packed terrace streets in Brockley or Crofton Park, we're also mindful of site tidiness and neighbour relations throughout.
How long does a typical Lewisham extension take to build?
A typical single storey rear extension takes 10 to 16 weeks from start on site to practical completion. Double storey, wraparound, and side extensions take 16 to 24 weeks. This is build time only — planning permission (where required) typically adds 8 to 13 weeks in Lewisham before work can begin. We'll give you a realistic programme in your quote and stick to it.
Extending Your
Home in Lewisham?
Tell us about your project and we'll come to you for a free, no-obligation consultation anywhere in the borough.
No pushy sales. No call centres. Just a straight conversation about your Lewisham project.