Kitchen Extensions Stanmore

A kitchen extension in Stanmore is mainly a question for its semis and detached houses: the VOA list puts 39% of homes here in that group, 11% in terraces and 45% in flats. Harrow judges the shape against its Residential Design Guide, which sets a maximum height on the boundary for a single storey rear extension and pulls any extra depth in from the side boundaries. We build the shell, the steel, the drains and the new kitchen as one programme, so the fit-out follows straight on from the building work.

In Stanmore, a rear kitchen extension of about 30 square metres typically costs £45,000 to £97,500 excluding VAT, or £60,000 to £100,000 for a side return (indicative London ranges, Resi, MyBuilder and Checkatrade, 2026). GS Renovation Ltd, a building contractor based in Potters Bar, does the work in Stanmore: the structural engineer we appoint designs the foundations and steel, we build the room and fit the kitchen, and a registered electrician certifies the electrics.

Which kitchen extension suits a Stanmore semi or detached house

On a Stanmore semi or detached house the main choice is between a full width rear addition and a wraparound, which also takes in the side where the plot has a gap to the boundary. The VOA figures put 39% of homes here in the semi-detached or detached group and 11% in terraces, so the narrow side return infill of terraced streets applies to fewer houses here. A wider plot gives you choices: a deeper room with a roof lantern, or a shallower one with a glazed corner facing the garden.

Those choices decide the structure. A full width opening across the back of a semi takes a steel beam on padstones, and a wraparound needs a second beam or a post where the side and rear walls meet. The structural engineer we appoint sizes both, and building control checks the calculations. Where a beam bears into the party wall, the Party Wall Act applies and you, as building owner, serve the notice. We order the steel once the calculations arrive, so the house is propped for as short a time as possible.

Housing in Stanmore

On the valuation list Stanmore counts about 6,860 homes, 45% flats and 55% houses; 4% predate 1919, 21% are interwar and 75% post-war. A detached house in Stanmore can set its kitchen extension where the garden gets the best light, with the drain run the main limit on the footprint, and 22% of homes here are detached.

Harrow's design guide sets the height and depth near your boundary

Harrow's Residential Design Guide SPD sets a maximum of 3 metres on the boundary for a flat roofed single storey rear extension beside a neighbouring home, or 3.5 metres at the mid point of a pitched roof. For a Stanmore kitchen that height has to hold the ceiling void, the roof build up, insulation and the upstand for any roof light. We check the section on the drawings against that figure before anything is ordered, because a parapet that creeps over it is expensive to take down later.

On a planning application, depth is tested against Harrow's two for one rule: any extra rear depth has to be set in from the side boundaries by twice the extra depth sought. On a Stanmore semi that can mean a stepped plan, deeper away from the party wall and shallower against it. The step changes the steelwork, the roof falls and where the rainwater goes, so we price and programme from the approved plan rather than an early sketch.

Prior approval, side glazing and the Stanmore conservation areas

Outside a conservation area, a single storey rear extension can go up to 8 metres on a detached Stanmore house, or 6 metres on a semi, through Harrow's larger householder extension prior approval. That route consults the immediate neighbours and can take 42 days, so the start date sits after it closes. Where a side wing is part of the design, Harrow's SPD treats large windows in a side wall within 3m of the boundary as unacceptable, which pushes the light into roof glazing and the rear wall instead.

Stanmore also has conservation areas with Article 4 directions on named properties. In Stanmore Hill Conservation Area one came into force on 20th June 2023 for Applegarth, The Glade and the Orchard in Green Lane, and Kerry Avenue and Little Common have their own. In a conservation area every side extension needs householder planning permission, and the larger extension prior approval route is not available. If your house is in one, the planning consent fixes the drawings, the brick and the window pattern before we order materials.

Public sewers, inspections and the kitchen fit-out in one Stanmore programme

Harrow insists on a full plans application, not a building notice, when an extension is built over or within 3m of a public drain or sewer. Behind a semi the shared run can pass close to the rear wall, so we trace the drains early and tell you which route the building regulations will take. Building over a public sewer also needs the water company's agreement, and a diverted run adds weeks, so it is better to know that before the footings are dug.

Harrow Building Control visits sites on weekdays between 10 in the morning and 3 in the afternoon, and offers a same day inspection if the office is phoned before 9:00, subject to surveyor availability. We book the footings, drainage and steel inspections into those windows so the trench is not left open. Once the shell is weathertight, first fix electrics and plumbing go in against the kitchen layout, and the units, worktops and appliances follow in the same Stanmore programme.

• Kitchen-diner layouts planned before the foundations
• Island units with power and waste run through the slab
• Wet underfloor heating laid in the new screed

VOA Council Tax stock of properties, March 2025, for Stanmore Park and Stanmore Uxbridge Road. Counts rounded by the VOA.

Two or three things usually come up alongside kitchen extensions on a Stanmore job: kitchen renovation in Stanmore, kitchen extensions across Harrow, a wraparound kitchen-diner, the Party Wall Act on a boundary build, kitchen extensions across London and Extend or Move?.

Why Choose GS Renovation in Stanmore

We run the whole Stanmore kitchen extension ourselves, from the footings and steel to the last cabinet door, so one programme covers the builders, the electrician and the kitchen fitter. You get a written schedule that shows where each Harrow inspection falls, and one point of contact from the survey to handover. The structural engineer we appoint and your designer work from the same drawings we build to. If your house needs a planning or prior approval decision first, we plan the start date around it.

• Building control and Part P certificates handed over together at the end
• Drains surveyed by camera before the footprint is fixed
• Materials priced at options, so you choose the finish

Checked by Abdelaaziz Saaid, founder and director of GS Renovation Ltd (Companies House no. 14611254). Structural design is by the consulting engineer appointed to your project.