How Much Do House Extension in Greenwich Cost?

The total expense of extending a house in the UK differs widely, shaped by the extension’s size, the materials chosen, and overall design complexity. Research shows that a single-storey rear extension might begin around £1,500 per square metre for a simpler design, while more standard projects fit into the £1,800–£2,500 per square metre band. If you introduce intricate steel supports, sophisticated glazing, or luxury finishes, you may exceed £3,000 per square metre.

In Greenwich, labour rates are not as steep as in the central boroughs but remain higher than outer areas, so homeowners might allocate more budget to refined or custom details. However, many historic properties—particularly in Greenwich’s conservation zones near the Old Royal Naval College or the UNESCO-listed areas—require specialised structural or heritage-driven approaches, pushing final costs up. Larger extensions can typically land between £40,000 and £100,000+, though narrower side-return plans can cost less, while a multi-level, high-end design can surpass regular brackets if advanced engineering or high-end decor is included. Adding a bathroom or kitchen generally inflates costs thanks to plumbing, waterproofing, and electrical complexities.

Whenever you examine bids from builders, ensure each one accounts for foundational tasks, structural framing, roofing, fixtures, finishing, plus labour overhead. Also confirm whether VAT—often 20%—is included. Though renovation sites and home-improvement magazines offer rough guidance, genuine accuracy comes from collating multiple quotes from reliable builders and evaluating each line item in detail.

Different Types Of Extensions

There are also different requirements for different extensions. Under is a list of the different types of house extensions:

Side extensions
Single storey extensions
Extensions more than one storey

They each have their own specific limits concerning such as rear extensions requirements, height, roofing and windows. For extensions of more than one storey, there is for example a requirement that roof pitch must match the existing house as far as practicable.

Greenwich

Greenwich, in southeast London, is renowned for its maritime history, expansive park, and a blend of old and modern residential districts. Families here often extend ground-floor living spaces to create an open-plan layout that connects with rear gardens, while side extensions can widen narrower floorplans in Edwardian or Victorian terraces. Loft conversions also flourish in Greenwich for extra bedrooms, especially if outward land is limited near terraced rows around West Greenwich. Basements can feature in certain more upscale streets, but because Greenwich includes heritage areas (like those around the Cutty Sark and Royal Park), obtaining planning permissions can demand extra detail.

Local contractors warn that traffic constraints around Greenwich Town Centre or near the A2 might complicate scheduling for skip drop-offs, so mid-morning or midday is often best. Labour rates align with standard London charges, but older or listed properties around Greenwich’s central zone might mandate thorough structural surveying to preserve historic character. This can raise your end cost. The benefit is that a skillfully orchestrated extension often amplifies day-to-day comfort while elevating your property’s value, especially if you remain near strong transport links such as Greenwich station or the DLR. Chatting with neighbours early helps, particularly if party walls or shared boundaries come into play.

Whether you envision a compact single-storey extension for a spacious kitchen-diner or an extensive multi-level plan to revamp older interiors, factoring Greenwich’s heritage identity and planning constraints is key to a cohesive design and smoother approval path.

Getting Started

Before building, pick which extension approach aligns with your property’s possibilities. A single-storey rear extension might enlarge a modest kitchen, a double storey adds more bedrooms upstairs, and a side expansion captures an alley or driveway. Alternatively, a loft or basement project can unlock extra levels if outward expansions aren’t an option. Basements in Greenwich can appear near higher-value houses, but they require careful planning due to potential conservation demands or local geology near the Thames.

Devoting time to planning from the outset typically minimises scheduling issues. Draft a detailed budget, scanning typical labour fees and material rates, plus leaving a cushion for refined finishes or mid-project surprises. If your design includes major structural reconfiguration, consider an architect or suitably qualified designer. Though a few building companies can do design-and-build, they typically want initial sketches or partial consent to quote accurately. Many Greenwich homeowners hire an architect for conceptual drawings first, then gather estimates from building firms.

Additionally, it’s wise to book a builder early on, as in-demand crews might be scheduled many months ahead. Obtaining multiple quotes lets you compare their breakdowns carefully, talk with references, and choose a contractor you trust. Experienced teams might refine your layout, possibly fitting in a separate utility nook or adjusting window placements for better daylight.

Project Management

Typically, you can organise your extension in two fundamental ways:

• Single contract (design-and-build or main contractor)
  You sign one agreement with a builder who manages every component—foundation tasks, carpentry, electrics, plumbing, roofing—and subcontracts specialized trades for about a 10–15% markup. You gain a streamlined schedule and a solitary point of contact.
• Multi-trade or split contract
  You act as the project coordinator, separately hiring groundworkers, carpenters, bricklayers, roofers, electricians, plumbers, etc. Though you might skip the main contractor’s overhead, you have to juggle each trade’s schedule. If a trade is late or incomplete, subsequent trades could be stuck waiting, inflating expenses or prolonging timelines.

For extensive or heritage-sensitive expansions in Greenwich, single-contract setups are popular among homeowners who can’t manage the day-to-day flow of trades. If you do multi-trade, be sure you can devote frequent time to confirm that each stage aligns seamlessly.

Do I Need Planning Permission?

Whether planning permission is essential hinges on your extension’s volume, height, and the property’s spot. Under Permitted Development Rights, you might enlarge your home without lodging a formal planning application if you stay within specific size and siting constraints. But if the design goes beyond them, you generally need a householder planning permission application.

Under are the general rules that apply to all extensions:
Only half the area of land around the "original house" can be covered by extensions or other buildings.
Extensions cannot be higher than the highest part of the existing roof; or higher at the eaves than the existing eaves.
Where the extension comes within two metres of the boundary the height at the eaves cannot exceed three metres.
Extension cannot be built forward of the ‘principal elevation’ or, where it fronts a highway, the ‘side elevation’.
The work cannot include:
verandas, balconies or raised platforms.
a microwave antenna (e.g. TV aerial or satellite dish).
a chimney, flue or soil and vent pipe.
any alteration to the roof of the existing house.
On Article 2(3) designated land the work cannot include cladding of the exterior.
The materials used in any exterior work must be of a similar appearance to those on the exterior of the existing house.
Source: Planning Portal.

Because Greenwich contains numerous conservation areas, such as those near the Old Royal Naval College or Greenwich Park, you should clarify whether your plan fits PD or calls for a planning submission. Seeking advice from the council early is wise.

Do I Need Planning Permission For A New Storey?

Loft extensions adding dormers or increasing roof height commonly require planning permission. Yet adding a new storey might fall under permitted development, as long as you obey specific conditions and file for prior approval. Otherwise, a Householder/Full Planning Permission path is needed. If your property adheres to these conditions, the bullet points below outline fundamental restrictions:

Number of additional storeys:
One storey can be added to a single storey house
Two storeys can be added if the house has more than one storey.

Height increases:
The house cannot exceed 18 metres in total height
Each added storey cannot add more than 3.5 metres to the total height
If not detached (e.g. terrace or semi) the total height cannot be more than 3.5 metres higher than the next highest building that the house is attached to, adjoins, or is in the same row as.
The additional storeys must be constructed on the principal part of the house*
The additional storeys must not exceed 3 metres in height or the height of any existing storey in the principal part of the house (measured internally from floor to ceiling)
Engineering operations must only include works within the existing curtilage of the house to strengthen existing walls and foundations
The materials used must be of a similar appearance to those used in the construction of the exterior of the current house
Windows must not be placed in any wall or roof slope forming a side elevation of the house.

There may be additional rules once the work is finalised. In a borough like Greenwich, known for consistent rooflines around heritage streets, verifying your plan meets local aesthetics is essential.

Do I Need Planning Permission For A New Basement?

Generally, digging a new basement needs planning permission, and large-scale excavation beneath ground level is similarly likely to require planning permission because of its major scope. It’s advisable to speak with your local authority early on, clarifying what they expect. Basement work is also inherently extensive; even if no direct planning application is demanded, Building Regulations must be met for structural soundness, safe exits, proper ventilation, fire safety, etc.

Always look at any local constraints that can override typical PD expansions. For instance, in certain historically significant parts of Greenwich, prior planning conditions might block underground developments. Explore the council’s guidelines or consult a planning specialist to confirm.

Around the borough’s prime or listed areas, basement expansions can be more expensive. Still, for owners lacking outward or upward possibilities, going underground might be the only solution.

Remember Building Regulations Application

Regardless of the size and shape of your extension, it must meet building regulations requirements. This is also regardless of whether you need planning permission or not.

You will need to submit a building regulations application. For smaller projects you can submit a Building notice but for larger extensions you’ll probably need a Full Plans Application. In this case full details of the proposed work will be submitted for approval before the work begins. With a Building Notice an inspector will inspect and approve the work as it is performed.

A Full Plans Application can catch design flaws or stability issues beforehand, whereas a Building Notice can suffice for a simpler single-storey project. Either route needs building control’s approval at the end to guarantee compliance with code standards.

The Difference Between Planning Permission And Building Regulations Application?

Whereas planning permission assesses whether the extensions meets local and national requirements, building control concerns structural safety and regulations compliance.

Even if you don’t require a planning submission (due to PD or other factors), building regulations are mandatory to ensure adequate foundations, insulation, damp resistance, and more. In Greenwich, older properties or listed buildings often demand extra structural attention for safety and historical preservation.

DIY Contribution

Homeowners sometimes consider tackling parts of an extension themselves. Painting, decorating, or landscaping can be good DIY tasks if you have the skills and time. Doing your own demolition, to an extent, can also be feasible—provided you understand which walls are load-bearing and follow safety precautions.

However, tasks such as electrical installation, gas connections, and structural changes almost always require qualified professionals. Mistakes in these areas can be costly and dangerous. Being realistic about your abilities is crucial; if you overcommit, you risk causing delays. Builders may need to pause until you finish a particular job, which can add to your final bill. If you’re determined to do some work yourself, consider hiring a professional for a consultation, as their input can help you avoid pitfalls.

Greenwich residents often carry out decorative or minor finishing tasks themselves after major structural phases wrap up, letting professionals handle core mechanics and ensuring the official build timeline stays on schedule.

Do I Need An Architect?

If your extension scheme is quite straightforward, you might rely on a structural engineer or building designer. Yet for bigger or more elaborate projects, an architect can provide crucial advantages. They consider aesthetics, room flow, and how new areas integrate with existing floors and any outdoor space.

They can also clarify whether your plan remains within PD or if you require planning permission. Though an architect’s fee increases initial outlays, their guidance often prevents layout missteps that spark bigger problems down the road.

Greenwich hosts a wide range of architectural styles, including Regency terraces in central parts, Victorian dwellings near Deptford, and post-war estates near Woolwich. An architect can help unify an older facade with a contemporary extension, making the most of vantage points near the Thames or local parks.

How Long Does It Take To Build An Extension?

An agreed timeline aids you in keeping track of progress. A basic single-storey rear job—if simple and built with standard materials—may only take weeks once the site is ready, especially under PD guidelines. Larger expansions, multi-level or multi-room, may last several months to half a year or more, depending on the structure’s scale and trade coordination.

Sometimes, you’ll need to temporarily move out if essential walls are removed or core utilities cut off. Even if you remain, dust, noise, and limited access to some rooms are typical.

Always buffer your schedule. Rain or freezing weather might halt external work, inspectors might request small revisions, or you could face late material deliveries. Drafting a sensible timetable with your builder helps limit stress, and finishing earlier than planned is a bonus. Likewise, a budget contingency addresses unforeseen design changes or structural repairs.

Greenwich sees moderate traffic near Greenwich Town Centre and popular tourist spots, so skip logistics typically aim for midday lulls. If you revise finishes or structural details partway through, that can extend your final timeline further.

House Extensions Step By Step

Though an extension is a large commitment, with detailed planning, capable teams, and a realistic budget, it can succeed. Whether you hope for a bigger kitchen-diner, new bedrooms, or a loft suite, understand each phase and the typical stumbling blocks.

1. Start by confirming what you want to achieve—more natural light, a larger social area, or additional bedrooms.
2. Then decide how best to organise the project.
3. Check if you need planning permission and what kind of building regulations application you need to send in.
4. Gather quotes from at least three builders if possible, ensuring each has a solid track record and good references.
5. Check that their quotes are like-for-like in terms of scope.
6. Factor in the cost of planning applications, building control fees, and professional services such as architectural drawings or structural engineering.
7. Then develop a realistic schedule, communicate frequently with your chosen contractor, and keep a close eye on both time and budget.
8. Finally, as the build nears completion, consider a thorough inspection—often called a snagging survey—conducted alongside your main contractor or an independent professional. Any leftover defects should be addressed before your final payment. Store compliance certificates, warranties, and other official approvals securely for any future mortgage or sale situation.

Once the extension receives its final approval, you can enjoy an enlarged living arrangement. Whether you fashioned a bright rear entertaining zone or added a second storey, the work often yields better daily comfort plus stronger property value. Greenwich owners, especially near the park or riverside, may see notable resale benefits if an extension complements the borough’s historical charm. The snagging survey ensures minor cracks or misaligned finishes are fixed. Filing building control sign-offs and warranties shows future buyers or lenders your extension was done properly. With that, your freshly expanded Greenwich home can cater to your living requirements for many years forward.

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