House Extensions Woolwich
Single storey rear and double storey extensions in Woolwich, planning, structure and build under one contract.
- Rated 4.9 from 31 reviews on MyBuilder
- Single-storey rear extension from £40,000
- Free site survey, itemised quote
GS Renovation plans and builds extensions across Woolwich, where most homes are flats and the houses are largely Victorian and Edwardian terraces. We handle everything from foundations and steelwork to the roof and final fit-out, whether your project is permitted development or needs a full planning application.
In Woolwich, a single-storey rear extension typically starts from £40,000, or £2,000 to £2,800 per m² (indicative London ranges, Architecture for London, Resi, MyBuilder and Checkatrade, 2026). GS Renovation Ltd, a building contractor based in Potters Bar, does the work in Woolwich: the structural engineer we appoint designs the structure, we build it, and building control signs it off.
Price guide
| Work | Indicative London range |
|---|---|
| Single-storey rear extension | from £40,000 |
| Rear extension, per m² | £2,000 to £2,800 |
| Side return, per m² | £2,400 to £3,200 |
| Wraparound, per m² | £2,400 to £3,200 |
| Double storey, per m² | £1,800 to £2,600 |
| Basement extension | see the basement page |
Indicative London ranges (Architecture for London, Resi, MyBuilder and Checkatrade, 2026), not a quotation. Prices checked September 2026. Full breakdown: Extension Costs & Planning.
Quick estimate for Woolwich
Woolwich range: choose above
Side return and rear extensions in Woolwich
On a Woolwich terrace, the classic extension fills the side return beside the original rear closet wing, widening a narrow galley kitchen into a proper kitchen-diner. On these Victorian and Edwardian plots we dig and pour new foundations, tie into the existing solid brickwork, and install steel beams to carry the old external wall once it is opened up. A rear extension across the full width adds even more space where the garden depth allows.
Many single storey rear and side-return projects on these SE18 terraces fall under permitted development, but that is never a given. Corner plots, previous extensions, a conservation area (where a side-return infill is no longer permitted development) and proximity to boundaries can all trigger the need for planning permission from the Royal Borough of Greenwich. We check the specifics of your property first and advise honestly which route applies, so there are no surprises once the work is under way.
Housing in Woolwich
By the valuation list's count, Woolwich holds about 21,990 homes, 26% houses and 74% flats; by age, 24% were built before 1919, 2% between the wars and 75% since 1945. Most homes here are flats, and a flat in Woolwich has no householder permitted development rights, so extending one needs planning permission and the freeholder's consent.
Sewers, flood risk and the Woolwich Conservation Area before extending
Two checks decide the route for a Woolwich extension before any drawing. Royal Greenwich requires a full plans application to build over or within three metres of a public sewer, so a building notice is not available for an extension near one. In a terrace the sewer connection can pass close behind the house. The other check is flood risk. Royal Greenwich requires a Flood Risk Assessment for all developments in Flood Zones 2 and 3, including domestic extensions, and Woolwich sits on the river, so find the address on the Environment Agency flood map first.
Then the conservation area. The Woolwich Conservation Area was designated in May 2019, and Royal Greenwich's Urban Design Guide says first-floor rear extensions are not classed as permitted development in conservation areas. For a Woolwich terrace inside the boundary, an upper storey over the closet wing is therefore a planning application from the start. Commission the survey, the drawings and the flood check together, so the application goes in complete rather than waiting on the one report nobody ordered.
Double storey and party wall work in SE18
A double storey extension adds a bedroom or bathroom above the new ground floor and suits many of the larger terraced houses around Woolwich. These almost always need a full planning application to the council rather than permitted development, along with building regulations for the structure, insulation and fire safety. We work from your architect's drawings, coordinate the engineer's calculations and book the building control inspections from start to finish.
Extending against a shared wall means the Party Wall Act applies, so you serve notice on the neighbours either side as building owner before we break ground, and we give you the drawings and programme it needs. Woolwich terraces sit close together, so we plan access, scaffolding and material deliveries carefully to keep the street and your neighbours onside. Once the shell is weathertight we carry out the full fit-out, tying the new space cleanly into the existing house.
Kitchen extensions in Woolwich
74% of homes in Woolwich are flats, and a flat has no householder permitted development, so a ground-floor flat's kitchen extension needs planning permission from the Royal Borough of Greenwich and the freeholder's consent. Most kitchen extensions here are on the 26% of homes that are houses. The fit-out is priced on its own page, kitchen renovation in Woolwich; the build figures are in the table above.
- Insulation, airtightness and thermal detailing to regulations
- Brickwork and mortar matched to the existing elevation
- Building control inspections at foundation, damp course and steel stages
VOA Council Tax stock of properties, March 2025, for all 6 statistical areas in Woolwich. Counts rounded by the VOA.
Why Woolwich Homeowners Choose GS Renovation
Woolwich clients choose GS Renovation because one team runs the whole extension, from groundworks and steel to plastering and decoration. We tell you upfront whether your SE18 project is permitted development or needs planning from the Royal Borough of Greenwich, manage building control and keep an occupied home liveable throughout. Our founder's 30+ years on the tools stand behind every build.
- Honest updates if a date or a detail has to move
- Weathertight shell reached before the fit-out begins
- Brick and mortar matched to the existing elevation
Reviewed jobs near Woolwich
1 MyBuilder review from Woolwich, with each customer's own job title:
- Replace kitchen extractor hob, Woolwich, 27 Apr 2024 (5 out of 5)
Read all 31 on our reviews page.
Built a new extension at rear of property. Laid foundations, drainage, raised floor, new roof and completed all fixtures and interior decoration…
Giorgio is an excellent and intelligent workman, and with very reasonable prices! He installed a kitchen extractor fan in a complicated situation…
George was brilliant. Lovely bloke, very reasonably priced and a perfectionist to boot. He completed our small kitchen renovation with care and great…
FAQ
Frequently Asked Questions about House Extensions Woolwich
Which parts of a house extensions project in Woolwich cost the most?
Labour and the making good usually cost the most on a house extensions project in Woolwich, within £2,000 to £2,800 per m² for a rear extension (indicative). The days on site at SE18 depend on access, condition and how many trades must follow each other: the planning route is confirmed before drawings, and footings inspected before concrete. GS Renovation sequences them to avoid idle time, which is the practical way to control cost.
Will my Woolwich extension need planning permission or is it permitted development?
Many single storey rear and side-return extensions on SE18 terraces are permitted development, but double storey work, corner plots, homes that have already been extended, or a side-return infill in a conservation area usually need a planning application to the Royal Borough of Greenwich. We assess your house first and confirm the correct route before design work begins. Building regulations always apply.
Are post-war Woolwich houses easier to extend than Victorian ones?
In some ways. Post-war houses frequently have cavity walls, concrete ground floors and simpler roofs, which makes tying new work in more predictable than joining solid Victorian brick. They can also have shallower foundations and drains under the likely footprint. The VOA dates 75% of Woolwich homes after 1945 and counts 74% as flats, so each house still needs its own survey before design.
Should my Woolwich extension have a flat or pitched roof?
That depends on the height available and what sits above. A flat roof keeps the eaves low beside the neighbour and suits rooflights or a lantern, while a pitched roof sheds water faster but needs height against the rear wall, which can clash with first floor windows. Either must meet Part L insulation levels, and a flat roof needs falls to a gutter so water does not pond.
Does my Woolwich extension need a party wall notice?
Frequently, on a terrace or semi. A beam end let into the shared brickwork needs two months' warning to next door, and foundations dug within 3 metres of their house to a level below its footings need one month's. If the neighbour objects rather than agreeing, each side's surveyor settles the terms in an award before building begins, so you serve the notices as soon as the design is fixed.
What paperwork should I receive at the end of a Woolwich extension?
A set worth keeping with the deeds. The Royal Borough of Greenwich's building control issues a completion certificate once the final inspection passes, the registered electrician certifies any new circuits under Part P, and a Gas Safe registered engineer records any boiler or gas work. Add the engineer's calculations, the drainage layout and any party wall award. A buyer's solicitor will ask for most of them when you sell.
Does a Woolwich extension have to pay the Community Infrastructure Levy?
It can fall within CIL, and relief has to be claimed. Royal Greenwich adopted its new CIL charging schedule on 24 July 2024 and it came into force on 26 July. Residential extensions and annexes, like self-build new homes, can claim relief using the published exemption forms. Ask Royal Greenwich which forms apply while the planning application is being prepared, and have the relief confirmed and filed with the approval before anyone breaks ground on site.
What happens if a tree stands near a planned extension in Woolwich?
Inside a conservation area, notice comes first. In Royal Greenwich conservation areas you must give six weeks written notice for work to, or felling of, trees more than 75mm in diameter. That includes cutting back roots or branches to make room for the foundations. Give the notice as soon as the footprint is known, so the six weeks run while the drawings are finished, and ask the structural engineer we appoint whether the tree changes the foundation depth.
Which certificates does Royal Greenwich want before a Woolwich extension is signed off?
Royal Greenwich may need an electrical installation certificate, a fire alarm commissioning certificate, a gas certificate and a double-glazing specification before completion of a domestic extension. Each comes from a different trade, and a missing one holds up the completion certificate. We collect them as each trade finishes rather than at the end. The glazing specification comes from the supplier rather than a trade on site, so ask for it when the doors and windows are ordered.
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