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Stanmore HA7 · House refurbishment

House refurbishment in Stanmore

Modernist, Victorian and Old World houses, appraisal by appraisal

A Stanmore house may stand inside one of Harrow’s four Stanmore conservation areas, each with its own December 2013 appraisal, or on one of the many streets outside them. This page sets out what those appraisals and Harrow’s Residential Design Guide say an owner may change on the house itself: windows, brickwork, roofs, rear additions and outbuildings, and the records worth finding before any of it is drawn.

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House refurbishment in Stanmore at a glance

Before a whole-house scheme is drawn, find which document speaks for your street. Inside the four conservation areas, Harrow’s appraisals carry guidance written for particular kinds of house: the Modernist houses on Kerry Avenue, the cottages, lodges and semi-detached pairs of Little Common, and the listed buildings and their grounds around Old Church Lane. For extensions and roofs anywhere in the borough, Harrow also has its Residential Design Guide of December 2010, which the Harrow Local Plan 2021–2041, adopted on 24 March 2026, still names. The cards and questions below show what each says about the outside of a house.

Harrow: Stanmore and Edgware conservation areas, with appraisals, maps and Article 4 entries · Harrow: Kerry Avenue Conservation Area Appraisal and Management Strategy, December 2013 (PDF) · Harrow: Little Common Conservation Area Appraisal and Management Strategy, December 2013 (PDF) · Harrow: Old Church Lane Conservation Area Appraisal and Management Strategy, December 2013 (PDF) · Harrow: Residential Design Guide Supplementary Planning Document (2010) · Harrow Local Plan 2021–2041, the adopted plan (PDF)

For the whole area, including conservation areas, permissions and working hours, read our Stanmore renovation guide.

Approved guide prices

What does a house refurbishment cost in Stanmore?

Cost in Stanmore depends on depth of work. A cosmetic refurbishment that keeps the existing layout runs £650–£1,250/sqm (typically £90,000–£180,000), while a back-to-brick renovation runs £2,250–£3,250/sqm (typically £275,000–£475,000), excluding VAT. A written scope and site assessment are needed before any project price can be fixed.

Scope of workGuide rateTypical total
Cosmetic — existing layout retained£650–£1,250/sqm£90,000–£180,000
Back-to-brick renovation£2,250–£3,250/sqm£275,000–£475,000
Typical programme16–32 weeks on site

Guide rates exclude VAT and are set by depth of work, not by postcode. Compare scopes in our London refurbishment cost-per-square-metre guide or try the cost calculator.

The buildings

Stanmore houses the council’s records describe closely

Beyond the character summaries of each conservation area, Harrow’s appraisals and its 2011 assessment of residential areas pick out particular kinds of house in more detail.

On Kerry Avenue, the December 2013 appraisal records pressure to replace the original Crittall steel windows, of which it says few survive, and their similar-style replacements with windows of non-traditional materials and designs, which it says would erode the unity of the area’s architectural detail. It turns to energy saving too, adding that other forms of insulation, in the roof or through draught-proofing, are just as effective, if not more, and less visually damaging than replacing the original single-glazed windows.

Harrow: Kerry Avenue Conservation Area Appraisal and Management Strategy, December 2013 (PDF)

Little Common’s appraisal notes that lodge buildings and some cottages there were always intended to be small-scale dwellings. Roof extensions are fairly common, it adds, with flat-roofed dormers on the outbuildings of Hill House and on the terraced Victorian cottages in the core of the area. It also warns that repointing soft bricks with a strong cement mortar makes their faces spall.

Harrow: Little Common Conservation Area Appraisal and Management Strategy, December 2013 (PDF)

Harrow’s 2011 Character Assessment gives three Stanmore streets as examples of unusual post-war architecture or layout: Water Gardens, a cul-de-sac of unusually designed detached houses on a narrow shared road surface; Bramble Close, terraced houses of more conventional design arranged around larger, more open squares; and Spring Lake, two-storey houses and bungalows of Scandinavian-influenced design on the slopes of the Harrow Weald Ridge, in the former grounds of Stanmore Hall. The assessment does not say whether these streets lie in a conservation area, so check Harrow’s map for the address.

Harrow: Character Assessment of Harrow’s Residential Areas, 2011 (PDF) · Harrow: Stanmore and Edgware conservation areas, with appraisals, maps and Article 4 entries

Permissions and local rules

What the appraisals say about the outside of a Stanmore house

Windows on Kerry Avenue

What can replace a Kerry Avenue window?

The appraisal says every window not of original manufacture should be replaced with metal frames in the Crittall style, and that altering opening sizes or window detailing is very unlikely to be appropriate today. Its management guidance resists replacements that lose features such as Crittall windows and railings, and traditional-style windows or doors in non-traditional materials. It encourages owners to swap plastic, aluminium or uPVC frames for metal ones, and says the Article 4(2) direction in place, which covers the houses on Harrow’s 1999 schedule, means replacement windows on those houses need to preserve or enhance the area’s character.

Harrow: Kerry Avenue Conservation Area Appraisal and Management Strategy, December 2013 (PDF) · Harrow: Kerry Avenue Conservation Area map, schedule and Article 4 directions (PDF)

Rear additions on Kerry Avenue

Can a Kerry Avenue house be extended?

The appraisal values the cubic massing of the area’s 1930s buildings. A second- or third-storey extension that infills a rear indentation will not be viewed favourably by the council, because the house’s architectural modulation would be lost. Extensions into the original sundecks would not usually be considered appropriate either, particularly above garages.

Harrow: Kerry Avenue Conservation Area Appraisal and Management Strategy, December 2013 (PDF)

Extensions and roofs in Little Common

How far can a Little Common house grow?

Little Common’s appraisal asks that an extension does not overpower the original building or upset the symmetry of a pair of semi-detached houses. In some places any extension may be unacceptable, or only a small single-storey one acceptable, and for lodges and some cottages it may be very difficult or impossible; each case is judged on its merits. On the roof, changes to the front slope are better avoided, while dormers and rooflights may be acceptable on rear slopes, kept as small and unobtrusive as possible.

Harrow: Little Common Conservation Area Appraisal and Management Strategy, December 2013 (PDF)

Listed buildings and their grounds around Old Church Lane

Why can a garden building need permission here?

A note on the Article 4 map in the Old Church Lane appraisal says that, as many of the area’s buildings are listed, listed building consent would be required for many works, and planning permission would be required to put up outbuildings in their grounds. The appraisal adds that, in some cases, no Article 4 direction was thought necessary because a building is flats, listed, a care home or bound by planning conditions restricting those rights, and so does not have the same permitted development rights as an unlisted single-family house.

Harrow: Old Church Lane Conservation Area Appraisal and Management Strategy, December 2013 (PDF)

Working hours, skips, parking and the conservation area maps for the whole area are in our Stanmore guide. Local guidance checked ; requirements depend on the address, the building and the complete proposal.

What the work covers

What a Stanmore house refurbishment covers

A schedule for every window and door

The survey lists each window and external door by elevation, notes whether it is original and whether it is timber, iron or metal, and records its condition. Repair, overhaul and secondary glazing are priced before replacement. In Little Common the appraisal says double glazing is unlikely to suit the area’s historic windows and suggests secondary glazing, unlikely to need planning permission but needing listed building consent for windows on a listed building; it also finds modern windows with storm-proofing, prominent trickle vents and top-hung vents not appropriate for historic buildings.

Harrow: Little Common Conservation Area Appraisal and Management Strategy, December 2013 (PDF)

Papers for earlier extensions and lofts

Before an older extension, loft or garage conversion is altered, the scope gathers its approvals. Harrow can supply building control certificates and copies of documents for a charge, but is only obliged to keep records for up to fifteen years. A regularisation application covers work started after November 1985 that was never notified; under Harrow’s charges for applications from 6 April 2026, it carries a single charge of 1.3 times the building notice charge, with no VAT. Missing papers are listed at the start, not found late.

Harrow: apply for Building Control · Harrow Building Control: domestic charges, Scheme No.15, Tables B and C, for applications from 6 April 2026 (PDF)

How we work

How we run a Stanmore house refurbishment

  1. Free feasibility visit

    We walk round the house with you and discuss what is feasible.

  2. Survey

    Rooms, levels and features to keep are measured, with opening-up or asbestos checks where needed.

  3. Design and consents

    Our own architects and structural engineers design the layout and structural openings, plan the service routes with them, and identify which consents and party wall notices apply.

  4. Price and contract

    A fixed written price and a JCT contract follow the survey, scope and specification. It records allowances, exclusions and how changes are priced.

  5. On site

    Work is inspected before it is covered, and a director reviews key decisions.

  6. Handover

    Testing, commissioning and snagging. Completed work carries a 12-month defects-rectification period under the JCT contract terms.

Real projects, clearly located

Examples of our house refurbishment work elsewhere in London

None of these projects is in Stanmore. Each card names where the work was done, so you can judge the finish and the approach before you brief your own.

Your brief

Before you ask for a quotation

  1. Place the house on Harrow’s map

    Send the full address and say whether Harrow’s current map puts it in the Kerry Avenue, Little Common, Old Church Lane or Stanmore Hill conservation area, or outside all four. If the house is on an Article 4 schedule or the statutory list, give the entry, so the design starts from the right rules.

  2. Describe the house as built and as altered

    Tell us whether the house is detached, semi-detached or terraced, what its roof is like (flat, hipped or gabled), which windows are original and what has been added since, such as a rear extension, dormer, garage or garden building. Give the year of each addition if you know it.

  3. List the outside changes you have in mind

    Keep inside work and outside work apart. Note each external change you are considering, whether windows, walls, roof, a rear addition, an outbuilding or paving, and say where the neighbours’ windows face, because Harrow’s rear-extension guidance and its 45-degree code both turn on the house next door.

Ready to take the next step? Send the address and a short outline of the work.

Book a free feasibility visit

Questions before you begin

House refurbishment in Stanmore: questions

What does Harrow’s design guide say about a single-storey rear extension?

Where permission is needed, start from Harrow’s 2010 Residential Design Guide. Subject to site considerations, an extension against a neighbouring home should be at most 3 metres high with a flat roof, or 3.5 metres at the mid-point of a pitched roof, both at the boundary. Where a greater depth is acceptable, the extra depth should be set away from any side boundary by twice that amount; chamfered extensions are not normally acceptable, except a purpose-built conservatory. Whether permission is needed turns on the national permitted development rules, Article 4 directions and planning conditions.

Harrow: Residential Design Guide Supplementary Planning Document, adopted 15 December 2010 (PDF, file 23276) · Householder permitted development technical guidance · Harrow: Stanmore and Edgware conservation areas, with appraisals, maps and Article 4 entries · Harrow: Old Church Lane Conservation Area Appraisal and Management Strategy, December 2013 (PDF)

Which loft and roof changes does the guide prefer?

On semi-detached and terraced houses it prefers a hip-to-gable with a rear roof extension or dormer, which must be set in at least 500 mm from a shared boundary and 1,000 mm from the gable end, and set back at least 1,000 mm from the eaves. Dormers should generally be subordinate, should not overlap or wrap around the hips and should never rise above the ridge. It advises against gabling a detached house’s hipped roof, and against floor-to-ceiling French doors or windows, possibly with railings creating a roof balcony. Read any appraisal too.

Harrow: Residential Design Guide Supplementary Planning Document, adopted 15 December 2010 (PDF, file 23276)

Is my Stanmore house at risk from Edgware Brook?

Harrow’s published figures do not answer that for one address. Its flood page lists Edgware Brook, Stanmore, with about 1,761 properties at risk, but names no streets, gives no date or source for the count and does not say all those properties are in Stanmore. Its 2011 assessment describes the brook running open from Bentley Priory to Uxbridge Road, then largely piped through the built-up area. Check the address with the GOV.UK long-term flood risk service; Harrow says owners in a flood zone are responsible for protecting their building.

Harrow: flood reporting and advice (undated page, checked 16 October 2026) · Harrow: Character Assessment of Harrow’s Residential Areas, 2011 (PDF) · Check long-term flood risk in England

Who looks after the private roads near Kerry Avenue?

The appraisal says Valencia Road, Glanleam Road and Upper Kerry Avenue are private roads, and that the residents are responsible for maintaining them; Harrow collects rubbish but has no other part in their upkeep. It does not say who agrees deliveries, parked vehicles or a skip on those roads, so before work starts, ask the residents who maintain the road and Harrow how access should be arranged.

Harrow: Kerry Avenue Conservation Area Appraisal and Management Strategy, December 2013 (PDF)

Who is responsible for Building Regulations on the project?

Harrow’s building control page says the applicant has a duty to ensure competent designers and contractors where they do not consider themselves competent, and that since October 2023 the duty holders include the applicant, client, principal designer and principal contractor. It also warns that several private building control providers, now called Registered Building Control Approvers, have cancelled applications or stopped trading, and that in some instances the work will then need to revert to the council. Ask who will approve the work before it starts.

Harrow: apply for Building Control

How much does a house refurbishment cost in Stanmore?

It depends on scope. In Stanmore, a cosmetic refurbishment keeping the existing layout runs £650–£1,250/sqm (typically £90,000–£180,000); a back-to-brick renovation runs £2,250–£3,250/sqm (typically £275,000–£475,000), excluding VAT. A written scope and site assessment come before any fixed price.

Book a free feasibility visit

Talk to us about your Stanmore house

Tell us the address and what you want to change in your Stanmore house. We reply within one working day, Monday to Friday, 8am to 6pm.

Or call 020 7101 3168. We serve Stanmore from our studio at Unit 3, Palace Court, 250 Finchley Road, London NW3 6DN.

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