House Extensions
in
Greenwich
Extension builders based in neighbouring Charlton — serving Greenwich's Georgian town houses, Victorian terraces in East Greenwich, Edwardian suburbs of Westcombe Park, and every property type in between. Local knowledge, honest pricing, end-to-end management.
Based in Charlton · Serving Greenwich
Planning to Handover
Free Site Consultations
On Your Doorstep.
Genuinely Local.
Kelmend Construction is based in Charlton SE7 — immediately adjacent to Greenwich. This isn't us claiming to cover an area from the other side of London. We've worked on houses across East and West Greenwich, Westcombe Park, Maze Hill, and Charlton for years, and the Royal Borough of Greenwich is our home patch as much as anywhere we work.
Greenwich itself contains more architectural variety than almost any other part of South London. The Georgian terraces around Crooms Hill and West Greenwich sit alongside Victorian working terraces in East Greenwich, the beautifully intact Edwardian suburb of Westcombe Park, and post-war housing further out. Each type requires a different approach — and the World Heritage Site designation that covers the core of Greenwich means that extensions here, particularly in and around the town centre, carry an extra layer of planning complexity that deserves specialist knowledge. Our house extensions service is built around exactly this kind of local, property-specific expertise.
We Know
Your Property
Georgian Town Houses
The Georgian terraces along Crooms Hill, Royal Hill, and the streets around Greenwich Park are among the most architecturally significant domestic buildings in South East London. Many are Grade II listed, most sit within the World Heritage Site setting, and all carry significant planning constraints. Extensions here are possible — but they require deep design sensitivity, careful material sourcing, and thorough engagement with Greenwich Council's heritage team.
Victorian Terraces
The Victorian terraces of East Greenwich — particularly around Woolwich Road, Trafalgar Road, and the streets running off them — are the backbone of Greenwich's residential stock. These properties were built for a different era of family life and almost universally benefit from rear or side return extensions. Outside the World Heritage Site buffer zone, many of these fall under permitted development.
Westcombe Park
Westcombe Park is one of the most intact Edwardian suburbs in South East London — a conservation area of consistent character, generous plots, and well-maintained properties. The mix of detached and semi-detached homes here offers real extension potential, particularly for double storey rear extensions and side additions. Design quality is held to a high standard by the conservation area designation.
Edwardian Semis & Villas
Maze Hill and the streets between Greenwich town centre and Westcombe Park contain a mix of Edwardian semis and larger detached villas — some within the World Heritage Site setting, some outside. These properties typically have generous room proportions and rear gardens that support well-designed extensions. The proximity to the park and the town centre makes them highly desirable and rewards investment in quality building work.
Victorian Villas & Larger Semis
The streets bordering Blackheath — particularly around Vanbrugh Park, Shooter's Hill Road, and Westcombe Hill — contain larger Victorian and Edwardian houses that offer significant extension potential. These tend to be higher-value properties where the return on a well-executed extension is substantial, and where design quality makes a visible difference to the final result and the value it adds.
Post-War & Modern Housing
The post-war and more recent housing in parts of Kidbrooke and the outer Greenwich area generally carries fewer planning constraints and more generous permitted development scope. These properties often deliver the most straightforward extension projects and the highest return on investment per pound spent — though proximity to the borough's conservation areas means we always check the specific address before assuming anything.
Types of
Extension
Rear Extension
The most commonly built extension across Greenwich — extends the ground floor into the rear garden to create open-plan kitchen and living space. Outside the World Heritage Site buffer zone and conservation areas, most single-storey rear extensions on Greenwich properties fall under permitted development. Within them, a planning application is required and design quality matters significantly.
Double Storey Extension
Adds rooms on both floors — typically a larger kitchen or living space below and an extra bedroom or bathroom above. Always requires planning permission. Greenwich Council pays close attention to how double storey extensions interact with neighbouring properties and the wider streetscape — particularly in conservation areas and the World Heritage Site setting.
Side Return Extension
Particularly effective on East Greenwich's Victorian terraces — fills in the narrow side alleyway to dramatically widen the kitchen or ground floor living space. Combined with a rear extension into a wraparound, this is one of the most transformative projects possible on a terrace. Often falls under permitted development outside conservation areas.
Wraparound Extension
Combines a rear extension and side return into a single L-shaped build — the most expansive ground-floor option for terraced and semi-detached properties. Very popular across Greenwich's Victorian and Edwardian terrace stock. Requires careful structural design and a planning application where conservation area rules apply.
Side Extension
Builds outward into the side passage or side garden of semi-detached and detached properties — commonly built on Westcombe Park and Maze Hill's wider-plot Edwardian homes. Can add a utility room, home office, or extend the existing footprint substantially. Design requirements depend on whether the property sits within a conservation area.
Garden Room Extension
A full-build extension designed for living in — not just looking out from. Large glazed doors, quality insulation, integrated heating. Particularly effective on Greenwich's larger plots around Westcombe Park, Maze Hill, and the Blackheath borders. Built to the same structural standard as the rest of the house.
What You Need
to Know
Greenwich has unique planning considerations that go beyond any other South London borough. The combination of the World Heritage Site designation, multiple conservation areas, and listed buildings means that understanding what applies to your specific address is essential before any extension design begins.
The World Heritage Site
Maritime Greenwich is a UNESCO World Heritage Site. The designation covers the Old Royal Naval College, the National Maritime Museum, Greenwich Park, and the Royal Observatory — and the setting of the WHS extends outward to include many residential streets. Extensions that could affect the setting, character, or views of the WHS receive particularly close scrutiny.
Conservation Areas
Greenwich has numerous conservation areas, each with its own character statement and design expectations. Westcombe Park, the Greenwich Town Centre, Charlton Village, Maze Hill, and others all carry conservation area status. Within these, design quality and material choices are subject to close review.
Listed Buildings
Greenwich has a high density of listed buildings — particularly in the town centre and around the park. If your property is listed, any extension — including those that would normally be permitted development — requires listed building consent in addition to any planning permission. We flag this immediately at the consultation stage.
Permitted Development
Outside conservation areas, Article 4 zones, and the curtilage of listed buildings, many Greenwich properties qualify for permitted development for single-storey rear extensions. We verify this for your specific address before any design work begins — given Greenwich's complex planning layers, assumptions can be expensive.
Typical Approval Timelines
Greenwich Council typically processes household applications within 8 weeks of validation. Applications touching on World Heritage Site setting, conservation areas, or listed buildings can take longer and may involve consultation with Historic England. We factor realistic timelines into every programme.
Party Wall & Neighbours
Most extensions in Greenwich involve party wall considerations — particularly the terrace and semi-detached stock across East Greenwich and Westcombe Park. We flag this early so notices can be served and any party wall agreements reached well ahead of the build start date.
Greenwich's
Heritage Areas
Greenwich has more heritage designations per square mile than almost any other part of London. If your property falls within — or adjacent to — any of these areas, it affects your extension options. We've worked across all of them:
Not sure whether your property is within a conservation area or the World Heritage Site setting? Greenwich's heritage layers are genuinely complex — the WHS boundary, the setting of the WHS, and the conservation area boundaries are all separate designations with different implications. We'll confirm for your specific address at the consultation stage and explain exactly what it means for your project.
Why Greenwich
Homeowners Choose Us
Based Next Door
We're in Charlton SE7 — five minutes from East Greenwich. When we say we know the area, we mean it literally. We've worked on properties across Greenwich, Westcombe Park, and East Greenwich for years and know the streets, the planning department, and the property types as well as anywhere we work.
World Heritage Site Experience
Working within or adjacent to the Maritime Greenwich World Heritage Site requires a level of planning knowledge and design sensitivity that most builders don't have. We've navigated these requirements successfully and know what Greenwich Council's heritage team expects before an application is submitted.
Family-Run, Directly Accountable
You deal with us throughout — not a sales team, not a site manager you've never met. On a borough where build quality is visible and neighbours notice, that accountability matters.
Itemised, Honest Quotes
Full line-item quotes — no vague allowances, no surprises. Any changes mid-project are costed in writing before we proceed. On Greenwich's higher-value properties, that transparency is particularly important.
Planning Handled
We advise on planning routes, work with architects familiar with Greenwich, and manage building control throughout. You won't be chasing the council or Historic England yourself — we handle it.
Quality That Matches the Setting
Greenwich's built environment sets a high bar. An extension that looks out of place on a Georgian terrace or a Westcombe Park Edwardian villa is a visible failure. We build to a standard appropriate to the properties and the setting we're working in.
Our Extension
Process in Greenwich
Free Consultation & Site Visit
We come to your Greenwich property — a short trip from our Charlton base. We walk the space, discuss what you want to achieve, and give you an honest read on what's feasible, what planning route applies (including WHS setting, conservation area, and listed building constraints for your specific address), and the realistic budget you're looking at.
Design & Planning
We work with your architect — or recommend one experienced with Royal Borough of Greenwich and the specific demands of the World Heritage Site setting — to develop drawings. We advise on the planning route, submit any required applications, and manage party wall notices where needed.
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 are all clearly set out before any work begins.
The Build
Work starts on the agreed date. We manage groundworks, structure, trades, and materials from our Charlton base — which means fast response if anything needs attention. Regular photo updates and direct access to us throughout. Site secured and cleaned every day.
Finishing & Fit-Out
Plastering, flooring, electrics, plumbing, and decoration coordinated as a single programme so there are no gaps between trades. The finish on a Greenwich property has to be right — we don't rush this stage.
Handover & Sign-Off
Royal Borough of Greenwich building control sign-off obtained. Full snagging walkthrough with you. We don't close the job until you're satisfied — and we're five minutes away if anything comes up afterwards.
Covering
the Whole Borough
We carry out house extensions across Greenwich and the Royal Borough. Our core areas include:
Greenwich Extension
FAQs
How much does an extension cost in Greenwich?
A single storey rear extension in Greenwich typically costs between £1,500 and £2,500 per square metre, depending on size, specification, and finish. Properties in the town centre, Westcombe Park, and the World Heritage Site setting often involve more complex planning processes and higher-specification materials, which can push costs toward the upper end. A 20m² kitchen extension might range from £30,000 to £55,000 fully finished. We'll give you an accurate figure after visiting your property and understanding what the planning context allows.
Does the World Heritage Site designation affect my extension?
It depends on where your property sits. The World Heritage Site itself covers the Old Royal Naval College, National Maritime Museum, Greenwich Park, and the Royal Observatory. Many residential properties fall outside the WHS boundary but within its "setting" — a broader zone where development that would harm the significance or views of the WHS is resisted. Properties within or adjacent to the setting face closer design scrutiny, and some extensions that would be permitted elsewhere may require more careful justification. We'll tell you exactly what applies to your specific address.
Do I need planning permission for an extension in Greenwich?
Not always. Many single storey rear extensions on Greenwich's Victorian and Edwardian properties fall under permitted development — particularly in East Greenwich and parts of Westcombe Park outside the core conservation areas. However, if your property is listed, sits within a conservation area, or falls within the World Heritage Site or its setting, planning permission is likely required. Greenwich's planning layers are complex and the only safe approach is to check your specific address — which we do at the start of every project.
Can I extend a listed building in Greenwich?
Yes — but any extension to a listed building requires both planning permission and listed building consent, regardless of size. The design must be sympathetic to the character of the listed building, use appropriate materials, and not harm the historic fabric or significance of the property. Greenwich has a high concentration of listed buildings — particularly in the town centre and around the park — and the council's heritage team is closely involved in any proposals affecting them. We've delivered extensions on listed buildings and understand the process.
How long does Greenwich Council take to approve planning applications?
The Royal Borough of Greenwich typically processes household planning applications within 8 weeks of validation. Applications involving listed buildings, conservation area consent, or the World Heritage Site setting can take longer — particularly where Historic England is consulted. We build realistic timelines into your programme from the start so that planning doesn't become a surprise delay.
Will an extension add value to my Greenwich home?
In most cases, significantly. Greenwich property values — particularly in Westcombe Park, Maze Hill, and the streets near the park and town centre — are among the highest in South East London. A well-built extension can add 10–20% to a property's value, and the absolute returns on higher-value Greenwich properties are substantial. The quality of the build and the design sensitivity matter enormously — particularly in conservation areas and the World Heritage Site setting where a poorly conceived extension can create planning complications and detract from value rather than adding it.
Can I stay in my Greenwich home during the extension?
In most cases, yes — and most of our Greenwich clients do. We plan the work carefully to minimise disruption, particularly when breaking through from the existing house into the new extension. We seal off dust, protect flooring and furnishings, and leave the site clean and secure at the end of every day. For more complex builds — full wraparounds, double storey extensions on Georgian properties — we'll discuss the programme honestly at the planning stage.
How long does a typical Greenwich 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 Greenwich before work can begin, and applications touching on heritage designations may take longer. We'll give you a realistic programme in your quote and stick to it.
Extending Your
Home in Greenwich?
We're based in neighbouring Charlton — a five-minute drive from your door. Tell us about your project and we'll come to you for a free, no-obligation consultation.
No pushy sales. No call centres. Just a straight conversation about your Greenwich project.