Kitchen Extension Cost in Streatham: 2026 Price Guide

A single-storey rear kitchen extension is one of the most popular projects among homeowners in Streatham, where a bustling town-centre stretch of late-Victorian retail buildings and residential mansion blocks, with Queen Anne-style suburban streets around Streatham Park. It's usually the difference between a cramped galley kitchen and a proper kitchen-diner opening onto the garden.

Typical costs

• Small extension (up to 15m²): roughly £30,000-£45,000
• Medium extension (15-25m²): roughly £45,000-£70,000
• Larger or wraparound extension (25m²+): £70,000 upwards

These figures are a guide, not a quote - they cover building work, a standard fit-out, and typical finishes. Bifold or sliding doors, roof lanterns, underfloor heating and a higher-spec kitchen will all add to the total.

What affects the price locally

In Streatham, the biggest local factor is usually access. Many streets are close terraces with no side access, which means materials have to be carried through the house and skips have to sit on the road - both of which builders will price in. Properties within the Streatham High Road & Streatham Hill, Streatham Common and Streatham Park conservation areas sometimes face tighter controls on matching brick, roofline and window styles to the existing building, which can add to material costs even for a rear extension that doesn't need planning permission.

Foundations are the other variable: older Victorian and Edwardian houses near Streatham Common and St Leonard's Church were often built on shallow footings, so a structural engineer may specify deeper or more extensive foundations than a newer property would need.

Do you need planning permission?

Many single-storey rear extensions fall under permitted development, but there are limits on how far you can extend without full planning permission, and those limits are usually tighter for terraced and semi-detached houses than detached ones. If your home is in one of Streatham's conservation areas, permitted development rights can be restricted further, so it's worth checking with the London Borough of Lambeth's planning department - or a builder who works in the area regularly - before you commit to a design.