Kitchen Extension Cost in Harrow on the Hill: 2026 Price Guide

Harrow on the Hill - where a hilltop village of Georgian townhouses, Tudor timber-framed cottages and grand Victorian school buildings along steep, winding streets - sees a steady stream of rear kitchen extensions, and for good reason: it's often the single change that makes the biggest difference to how a house actually lives day to day.

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

The single biggest cost variable for a kitchen extension in Harrow on the Hill tends to be access rather than the extension itself - narrow terraced streets with no side passage mean materials and spoil go through the house, which shows up in the price. On top of that, 8 conservation areas covering the Hill - over a third of all Harrow's conservation areas, among the earliest designated in England often means closer attention to matching brick, roofline and windows, adding cost even where planning permission itself isn't required.

Foundations are the other variable: older Victorian and Edwardian houses near Harrow School and St Mary'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?

Permitted development covers a lot of single-storey rear extensions, but not without limits, and those limits bite harder on terraced and semi-detached houses than detached ones. Inside Harrow on the Hill's conservation areas, expect those rights to be trimmed back further still - check with the London Borough of Harrow's planning department, or a builder who already works locally, before finalising a design.