House Extension & Loft Conversion Costs in Beckton (2026)

Beckton extension and loft conversion costs: 2026 table

We price Beckton projects with our calculator method: national build rates per m² for each type of work, the London multiplier of 1.25, design fees of 4–7% of the build, a structural engineer, building control, a lawful development certificate or planning fee, and 20% VAT. The figures are modelled estimates, not quotes from Newham builders.

Project	Size	Basic	Standard	High-end
Single-storey rear extension	20m²	£58,000 – £75,500	£70,000 – £91,500	£86,000 – £117,000
Kitchen extension with mid-range kitchen	25m²	£90,000 – £129,000	£105,500 – £149,000	£125,000 – £181,000
Single-storey side extension	15m²	£43,500 – £57,500	£53,000 – £69,500	£65,000 – £89,000
Two-storey extension (planning)	40m²	£101,500 – £130,000	£123,500 – £159,000	£151,500 – £204,000
Rear dormer loft conversion	30m²	£52,500 – £78,000	£58,500 – £88,500	£72,500 – £105,500
Hip to gable loft conversion	30m²	£65,000 – £90,500	£71,000 – £101,000	£87,000 – £121,500
Rooflight (Velux) loft conversion	25m²	£25,500 – £38,000	£29,000 – £43,000	£35,500 – £51,500
Garage conversion	15m²	£12,000 – £18,500	£16,500 – £24,500	£22,500 – £32,000

At a standard finish, the build-only rates are £2,750–£3,375 per m² for a single-storey or kitchen extension, £2,438–£3,000 per m² for a two-storey extension, £1,525–£2,175 per m² for a rear dormer and £1,850–£2,500 per m² for a hip to gable, all ex VAT. Our London-wide guides to house extension costs in London and loft conversion costs in London explain where Beckton sits against inner London prices.

We have left side return and mansard rows out deliberately. Beckton has almost none of the Victorian back-addition terraces that make a side return extension or mansard the default elsewhere in London.

Beckton’s housing: what was built and what you can add

Beckton was the London base of the Gas Light and Coke Company from 1870 and home to one of the country’s largest sewage works. After the docks closed, regeneration from 1981 brought business parks and thousands of new homes; Hidden London describes North Beckton as mostly built up in the late 1980s, with short streets and small homes, many of them built under social housing schemes. Newham Council’s own resident profile simply calls Beckton “a residential area, with houses built in the 1980s”.

Newham’s Characterisation Study (2024) is more precise. It describes Beckton’s dominant character as 1980s to early 1990s London Docklands Development Corporation estate housing: “largely suburban, extensive low-rise, car-centric residential development”. It identifies three common house types:

• Dominant: two-storey brick semi-detached houses behind a low brick wall, with a front garden and parking space, and pitched roofs often in terracotta tiles.
• Secondary: brick and timber-clad detached houses of two to three storeys, often with usable attic space.
• Tertiary: brick detached houses and low-rise flats, averaging three storeys with liveable attic space.

The study adds that every house has a back garden, that streets form a grid of curving roads serving cul-de-sacs, and that “the majority of the existing housing stock has not changed or been redeveloped since it was first built”. In other words, many Beckton houses still have room to extend.

What this means for your project

• Semis: a 3m rear extension under permitted development (or up to 6m with prior approval), a single-storey side extension where there is a gap to the boundary, or both as an L-shape.
• Detached houses: up to 4m at the rear under permitted development, and more scope for a two-storey extension with planning.
• Houses with existing attic rooms: the three-storey types may already use the roof space, so a rear dormer can be an upgrade rather than a full conversion.
• Flats: the low-rise apartment blocks have no householder permitted development rights; any external change needs planning and the freeholder’s consent.

Loft conversions in 1980s houses

Houses of this age are typically roofed with factory-made trussed rafters, whose diagonal webs fill the loft. Converting means replacing them with a new structure of steel beams and timber, designed by a structural engineer, which is why the engineer’s fee sits toward the top of the £500–£2,500 range on these homes. Shallow roof pitches can also limit headroom; measure from the top of the ceiling joists to the underside of the ridge before you get excited. Where headroom works, a rear dormer is the usual answer, with a hip to gable only on houses with hipped roofs.

Planning permission in Beckton: Newham Council rules

The London Borough of Newham is the planning authority for Beckton. National permitted development rules apply to houses: single-storey rear extensions of 3m on semis and terraces and 4m on detached houses, side extensions of one storey up to half the width of the original house, and loft enlargements of 50m³ on semis and detached houses (40m³ on terraces). Newham charges the national fees: £274 for a lawful development certificate and £548 for a householder application. See our full guides to extension planning permission and loft conversion planning permission.

Newham’s Altering and Extending Your Home SPD

Where you need planning, Newham assesses your scheme against its Altering and Extending Your Home supplementary planning document (adopted February 2018). Unlike some boroughs’ guides, it sets principles rather than fixed measurements. The points that matter most for Beckton houses:

• Side extensions should show clear set-backs from the existing walls, so the original house still reads as the main building.
• Roof alterations should keep street-facing roof slopes, ridge lines and chimneys intact. In a street of matching 1980s semis, that makes a rear dormer far easier to approve than any change to the front roof.
• Neighbours should keep reasonable daylight, sunlight, privacy and outlook, with special attention to shared boundaries.
• Materials should be high quality and either match the house or contrast deliberately. On Beckton’s brick semis, matching brick and tiles is the simplest route.
• Outbuildings should be small and keep the rear garden open.

Newham’s new Local Plan was submitted for examination in July 2025, and the inspector has reported that it is sound subject to modifications; full Council must vote to adopt it. Ask your designer to check which policies are in force when you apply.

Conservation areas and Article 4 directions

Newham has nine conservation areas. The three with Article 4 directions (Durham Road, Romford Road and Woodgrange Road) are in the north of the borough, not Beckton, and the borough’s other Article 4 direction controls houses in multiple occupation rather than family extensions. Most Beckton homes are therefore unaffected, but check the council’s map and your house’s original planning permission, because estate permissions sometimes removed permitted development rights by condition.

Practical Beckton factors: flood risk, ground, parking and permits

• Flood risk: Newham’s 2025 Strategic Flood Risk Assessment names Beckton among areas at risk from the River Roding, which runs along the borough’s eastern edge, and among the areas affected if the Thames tidal defences were breached. Householder applications in Flood Zones 2 or 3 need a short flood risk statement, usually following the Environment Agency’s standing advice on floor levels and flood-resilient construction.
• Former industrial land: the Beckton Alps were landscaped from a tip of gasworks waste. If your house is near former industrial land, your engineer may suggest a trial pit before choosing foundations.
• Skips: the characterisation study notes most houses have a front parking space, so a skip can often sit on your own drive without a permit. On the road, Newham only issues skip permits to approved skip companies; allow 24 hours, and expect a £150 fixed penalty for an unpermitted skip.
• Scaffolding: a licence is needed for any scaffold on the pavement. Newham wants at least 15 working days’ notice, charges £114 if an officer site visit is needed, and takes a refundable deposit; the fee depends on the size and duration of the structure.
• Party walls: on a semi, a rear extension near the boundary or steels into the shared wall usually triggers the Party Wall etc. Act 1996 with one neighbour. Detached houses often avoid it altogether. Our party wall agreement guide and surveyor cost guide explain the process and fees.

How long does a Beckton project take?

1. Survey and drawings: 3–5 weeks for a standard semi.
2. Certificate or planning: around 8 weeks for a decision; prior approval for a 3m–6m rear extension also takes up to 42 days.
3. Party wall: notices give the neighbour 14 days to respond; awards can take a month or more if surveyors are appointed.
4. Build: as a rough guide, 8–12 weeks for a single-storey extension on a clear site and 6–10 weeks for a dormer loft.

Does extending add value in Beckton?

HM Land Registry puts the average Newham price at £388,045 in August 2026, down 4.7% on a year earlier and well below London’s average of roughly £554,000. That gap is the key point for Beckton: you pay London build prices on homes valued below the London norm, so the value ceiling for your street matters more than it would in a dearer borough. An extra bedroom in a loft, or a bigger kitchen in a family semi, is often still cheaper than moving within London once stamp duty and fees are counted. Check sold prices for extended houses nearby, and if you need to borrow, see how to finance an extension.

Saving money on a Beckton extension or loft

• Use permitted development and a £274 certificate rather than a £548 application where the design allows.
• Repeat what neighbours have done: on estates of near-identical houses, a design already approved next door is a useful template for drawings and pricing.
• Use your drive for skips and deliveries to avoid licence costs and delays.
• Get the engineer in early on loft projects so trussed-rafter replacement is priced from the start.
• Try the loft conversion cost calculator to compare a dormer against a rooflight-only conversion.

Beckton extension and loft conversion FAQs

How much does an extension cost in Beckton?

On our 2026 model, a 20m² single-storey rear extension costs about £70,000–£91,500 with a standard finish, fees and VAT. A 25m² kitchen extension including a mid-range kitchen is around £105,500–£149,000.

How much is a loft conversion in Newham?

Around £58,500–£88,500 for a 30m² rear dormer and £71,000–£101,000 for a hip to gable, at London prices. A rooflight-only conversion of 25m² is about £29,000–£43,000.

Do I need planning permission for an extension in Beckton?

Often not. Most Beckton houses keep their permitted development rights, so a 3m rear extension on a semi or a rear dormer can go ahead with a lawful development certificate. Check your original planning permission in case rights were removed, and remember flats have none.

Can I convert the loft in a 1980s house?

Usually, if there is enough height. The trussed rafters found in most houses of this age must be replaced with a new steel and timber structure, which adds engineering and labour cost.

Is Beckton in a flood zone?

Parts of it are. Newham’s flood risk assessment identifies Beckton as at risk from the River Roding and in a Thames defence breach. A planning application there needs a simple flood risk statement.

Do I need a party wall agreement in Beckton?

On a semi, usually yes with the attached neighbour. If they consent in writing, there is no surveyor’s fee; otherwise budget £1,000–£3,000.

Costs in other areas: London extensions · London lofts · Leatherhead · Portsmouth · Maidstone · Essex · Peterborough · Bristol · Birmingham · Nottingham · Manchester · Leeds · Liverpool · Llanelli · Glasgow · All areas compared

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