GSM Builders Ltd designs and builds house extensions in Ealing – W5, W13 and W7, from Ealing Broadway and Ealing Common to Northfields, West Ealing and Hanwell. We are based in Hayes, about 20 minutes west, and Ealing’s Victorian and Edwardian terraces are the houses we most enjoy extending: the side return, the long garden and the high ceilings all reward a well-designed extension.
Want a number first? Use our free extension cost calculator for an instant 2026 range, then book a free survey for a fixed price.
The Ealing extension: side returns and Victorian terraces
Most Ealing houses were built between 1880 and 1914. They have a narrow galley kitchen at the back with a side alley beside it – the side return. Infilling that alley with a glazed roof widens the kitchen by 1.5–2.5 m and is the single most transformative thing you can do to a Victorian terrace. Combined with a 3 m rear extension it becomes an L-shaped or wrap-around extension: a full-width kitchen, dining and family room opening onto the garden.
On the larger Edwardian semis around Ealing Common, Castlebar and Hanger Hill, double-storey rear extensions add a bedroom and bathroom above the new kitchen. In Hanwell and Northfields the 1930s semis take the same 3–6 m rear extensions we build across Hillingdon and Hounslow.
Extension costs in Ealing (2026)
| Extension | Typical size | Indicative cost (ex VAT) | Build time |
|---|---|---|---|
| Single-storey rear, 3 m | 18–22 m² | £53,000 – £74,000 | 8–10 weeks |
| Single-storey rear, 6 m (prior approval) | 30–36 m² | £79,000 – £116,000 | 10–12 weeks |
| Side-return | 8–12 m² | £42,000 – £63,000 | 8–10 weeks |
| Wrap-around | 30–40 m² | £89,000 – £137,000 | 12–14 weeks |
| Double-storey rear | 40–50 m² | £116,000 – £168,000 | 14–18 weeks |
Ealing prices run around 5% above Hillingdon because access on terraces is tighter (everything comes through the house) and specifications tend to be higher. See the full cost guide.
Planning permission in Ealing – conservation areas matter
Ealing Council has more than 25 conservation areas, and many carry Article 4 directions that remove permitted development rights for rear extensions and roof alterations – Ealing Common, Ealing Green, Castlebar, Hanger Hill Garden Estate, Brentham Garden Suburb, Northfields (Grosvenor Road) and parts of Hanwell among them. In these streets even a 3 m rear extension needs a full householder application (£258, eight weeks), and the council will expect materials and rooflines that respect the terrace.
Outside conservation areas the usual rules apply: 3 m rear extensions (6 m with prior approval) and single-storey side extensions up to half the width of the house are permitted development. Flats – a large share of Ealing’s housing – always need planning permission and, if leasehold, the freeholder’s consent. We check your address on the council’s conservation map before we quote and handle the whole application.
Because almost every Ealing house shares a wall, the Party Wall Act applies to nearly every extension. We serve the notices and work with your surveyor.
How we run an extension
- Free site visit and itemised quote
- Drawings and structural calculations for planning and Building Regulations
- Planning or prior approval submitted to Ealing Council and managed by us; Lawful Development Certificate where permitted development applies
- Party Wall notices served and surveyors coordinated
- Build with a dedicated site manager – foundations, drainage, steel, walls, roof, glazing, first fix, plaster, second fix, decoration
- Building Control completion certificate, snagging and a 12-month workmanship warranty
Why GSM Builders Ltd for an extension in Ealing
- Family-run building company based at Leven Way, Hayes – 20 minutes from Ealing
- One contract from drawings to completion certificate
- Written, itemised price with agreed payment stages
- Fully insured, Building Control certified, 12-month warranty
- Experienced with Ealing’s housing stock and its council’s planning rules
Nearby
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Ealing extension FAQs
How much does a side-return extension cost in Ealing?
A side-return extension on an Ealing terrace typically costs £42,000–£63,000 excluding VAT and the kitchen; combined with a 3 m rear extension as a wrap-around, £90,000–£135,000. GSM Builders Ltd quotes free after a site visit.
Do I need planning permission for an extension in Ealing?
If your house is in one of Ealing’s conservation areas with an Article 4 direction – such as Ealing Common, Ealing Green or Castlebar – yes, even for a small rear extension. Elsewhere, 3 m rear extensions (6 m with prior approval) are usually permitted development. Flats always need permission.
Can you extend a Victorian terrace with no side access?
Yes. Most of our Ealing projects have no side access; materials and spoil go through the house with floor and wall protection, and skips are placed on the road under a council permit.
Which parts of Ealing do you cover?
Ealing Broadway, Ealing Common, South Ealing, Northfields, West Ealing, Hanwell, Castlebar, Hanger Hill and Pitshanger. We are based in Hayes, around 20 minutes away.
Start your Ealing extension
Send us your address and a couple of photos and we will check the planning position and arrange a free site visit.