Side return, rear and wraparound extensions for Balham's Victorian and Edwardian terraces. Free site visit, then an itemised fixed-price quote.
Balham is in Wandsworth borough and is mostly terraces, so most ground-floor projects here are a side return, a rear extension or both. We haven't got a finished Balham extension on the site yet. The nearest ground-floor job is our Earlsfield side return, elsewhere in Wandsworth borough: 200 sq ft, bi-fold doors and underfloor heating, eight weeks on site.
We publish one typical band, for the kitchen and side return extensions most terraces here get. Rear, wraparound and double-storey extensions are priced at the site visit.
| Type | Typical build price (ex VAT) | Notes |
|---|---|---|
| Kitchen / side return extension | £90,000–£100,000 | Typical build price; kitchen and flooring supplied by you. |
| Single-storey rear extension | Priced at site visit | Size, structure and glazing vary too much for a fair band. |
| Wraparound (side return + rear) | Priced at site visit | Usually needs a householder planning application. |
| Double-storey extension | Priced at site visit | Needs planning permission; priced once the design is known. |
Typical project build prices, excluding VAT and professional fees (design, structural engineer, Building Control, party wall and planning fees). Prices are the same across every borough we cover; access and logistics (parking, skips, scaffold, restricted access) can affect the final price. Your fixed quote follows a site visit.
Our fixed-price quote is based on the agreed written scope. Client-requested changes and unforeseen work are priced and approved separately before proceeding.
Between Balham High Road and Tooting Bec Common is the Heaver Estate, built by Alfred Heaver between about 1890 and 1910 in the Queen Anne style. It's a conservation area with an Article 4 Direction that covers street-facing changes and, unusually, painting the outside walls. As a conservation area, side extensions and rear extensions of more than one storey there need a householder application (£548 from April 2026), and the 6m prior approval route isn't available.
Under the national rules, a single-storey rear extension can go 3m beyond the original rear wall of a terraced or semi-detached house as permitted development, or up to 6m through prior approval, where the council notifies neighbours and has 42 days to decide. A side infill beside the back addition must be single storey, no more than 4m high and no wider than half the original house. In a conservation area, side extensions, rear extensions of more than one storey and the 6m route are all removed.
If you're relying on permitted development, a Lawful Development Certificate (£274 from April 2026) gives you proof for a future sale. In our London Planning Datahub pull of 2 October 2026, Wandsworth refused about 15% of the proposed-use certificates it decided in the year, so the drawings need to be accurate.
Wandsworth's Housing SPD covers rear and side extensions to terraced houses, including the effect on neighbours' light. A design that respects the back addition, rather than swallowing it, generally goes through more smoothly. Our Wandsworth kitchen extension cost and timeline post walks through a typical programme.
On a terrace, almost every extension involves the Party Wall Act, for example a new flank wall on the boundary or steel cut into a shared wall. We flag the likely notices early and give the surveyor the construction information they need. Our party wall notice timeline sets out the steps.
We don't have a published extension in Balham itself yet, so these are our nearest completed projects. Each one links to the full write-up with photos.
Earlsfield, Wandsworth, SW18
8 weeks on site · 200 sq ft extension
Wandsworth, South West London, SW18
10 weeks on site · 350 sq ft extension
Clapham, South West London, SW4
“We worked with Bluebird on our kitchen extension project. Highly recommend. They were transparent, easy to work with, had top tradesmen who care about delivering a good build and were always happy to create solutions as we progressed. Thanks Ben, Tom and Milen!”
Step 1
We visit, measure up and assess the existing structure, access and any party wall implications, then explain the practical next steps. No obligation.
Step 2
An itemised quote for the build, excluding VAT and professional fees (design, structural engineer, Building Control, party wall and planning fees), which are quoted separately.
Step 3
Working with your architect, the drawings are developed and submitted for planning if required, and party wall notices are served to neighbours if needed. We plan the start date around them.
Step 4
The programme is set out before work starts. If you change the scope, we price the change and agree it with you first.
Step 5
Final inspection, a snagging walk-through with you, and keys handed over.
Bluebird Spaces is a member of the Federation of Master Builders.
View our FMB profileCall us, or send the enquiry form and we'll arrange a free site visit.
Free consultation. Clear, itemised quote. No deposit upfront.
