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Mill Hill NW7 · House refurbishment

House refurbishment in Mill Hill

Timber frames, peg tiles and Arts and Crafts houses in Mill Hill

A Mill Hill house refurbishment begins with the fabric that Barnet’s 2008 appraisal of the conservation area describes: timber frames given new fronts of weatherboard or brick, lime render lined out to look like stone, and sashes that mix pane sizes in a single window. The appraisal adds that the Article 4 direction made in 1970 was updated with successive permitted development orders, and in the parts it covers it lists oil tanks and satellite dishes among the controlled works.

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Serving Mill Hill from our Hampstead studio · NW3 6DN
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House refurbishment in Mill Hill at a glance

Barnet’s 2008 appraisal lists small changes among the problems it found on Mill Hill’s older homes. On groups of modest cottages in Nan Clarks Lane and along Highwood Hill it records minor alterations such as replacement windows, doors, surfacing materials and satellite dishes. In Mill Hill Village it says minor alterations such as new windows, doors, boundaries, gates and porches take away from the special qualities of the houses. So before you order a single window, door or gate, photograph the front of your house and list what it still keeps.

Barnet: Mill Hill Conservation Area Character Appraisal Statement, adopted April 2008 (PDF)

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

Approved guide prices

What does a house refurbishment cost in Mill Hill?

Cost in Mill Hill 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

Timber frames, cottages and Arts and Crafts houses: what Barnet recorded

The 2008 appraisal describes the buildings of the Mill Hill Conservation Area material by material. It is a record of that year, so walk round your own house with it and note which details have survived and which have gone since.

Most of the medieval buildings in the conservation area were timber-framed, the appraisal says, with infill panels faced in daub, and buildings were often given new fronts of weatherboarding or brick parapets in the 18th and 19th centuries. Some earlier frames were re-faced in lime render, often lined out to imitate stone, to give a Georgian front. Rendered buildings are often now painted white or a pastel colour, the appraisal adds, such as West Grove and West Grove Cottage in Hammers Lane. We check what lies behind a rendered front before any wall is opened.

Barnet: Mill Hill Conservation Area Character Appraisal Statement, adopted April 2008 (PDF)

Among the listed cottages on The Ridgeway, St Francis and St Mary’s Cottages are early 19th-century weatherboarded cottages with hipped tiled roofs and sashes with glazing bars, and Church Cottages are 18th-century red brick with 19th-century trellis porches. Around the Three Hammers, the appraisal describes development as subordinate in scale and style. It notes a deliberate mix of pane sizes within one building and even within one window, such as an upper sash with several divisions over a lower sash of two panes.

Barnet: Mill Hill Conservation Area Character Appraisal Statement, adopted April 2008 (PDF)

The Arts and Crafts houses, usually of two storeys and occasionally single-storey bungalows, have features such as clay-tiled roofs with bonnet tiles, sweeping eaves, exposed rafter feet, decorative soffits, neatly detailed dormers, canted bays, tile creasing and tile hanging. Lead appears now and then on flat or curved dormers and porches, as at Ridgeway House on Wills Grove. Older clay roofs were laid with peg tiles fixed by two small pegs, while Welsh slate allowed pitches as shallow as about 22 degrees. Ask your roofer to record the tile, eaves and pitch before anything is stripped.

Barnet: Mill Hill Conservation Area Character Appraisal Statement, adopted April 2008 (PDF)

Permissions and local rules

Checks on the outside of a Mill Hill house

The direction made in 1970

Which outside works does the older Article 4 direction bring under control?

In 2008 the appraisal described the Article 4 direction made in 1970 as updated with successive General Permitted Development Orders, and in the parts it covers it lists the installation of oil tanks and satellite dishes among the controlled works. Barnet’s conservation page explains that a direction bans nothing by itself; it means applying for consent first. So before an oil tank, a dish or other outside equipment is placed, check the orders and their January 1991 schedule of affected properties for your house.

Barnet: Mill Hill Conservation Area Character Appraisal Statement, adopted April 2008 (PDF) · Barnet: Article 4 directions in the Mill Hill Conservation Area, 1970 to 1991 (scanned PDF) · Barnet conservation areas, appraisals and maps

The Retail Trust Cottages

What does the Article 4(2) direction cover on Hammers Lane?

Barnet’s Article 4(2) order for the Retail Trust Cottages, on both sides of Hammers Lane, lists works that need permission where they would front a highway, waterway or open space. Among them are alterations to a roof slope, a porch at an external door, hard surfaces, satellite antennas, gates, fences and walls, and painting the outside. Planning Data maps the direction as two areas, so read the order against your cottage before planning work to its front.

Barnet: Mill Hill Conservation Area Article 4(2) direction (PDF) · Planning Data: Article 4(2) for Mill Hill CA, Area 1 · Planning Data: Article 4(2) for Mill Hill CA, Area 2

Listed houses

What does Barnet look for in changes to a listed house?

The appraisal sets out six points that works to a listed building should normally meet. Among them, works should be secondary in bulk and form to the main building, materials and detailing should be of high quality, and particular attention should go to roof lines, roof shape, eaves and verge details and chimneys. For a listed house, draw these elements as they are now and as proposed, so the application shows each change against the original.

Barnet: Mill Hill Conservation Area Character Appraisal Statement, adopted April 2008 (PDF)

Houses marked positive

Does an unlisted house here get extra scrutiny?

It can. The appraisal marks many 19th- and early 20th-century homes as positive buildings and says Barnet will ensure each application to extend or alter one is assessed with particular care. For conservation areas, the Local Plan says alterations should normally be made in materials matching the original, and that the council will consider putting back lost traditional features where there is evidence enough for an accurate copy. Old photographs, or the same detail surviving on a neighbouring house, can help show what was there.

Barnet: Mill Hill Conservation Area Character Appraisal Statement, adopted April 2008 (PDF) · Barnet Local Plan 2021–2036, adopted 4 March 2025: the plan and its adoption documents

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

What the work covers

What a Mill Hill house refurbishment covers

Roofs, eaves and chimneys

We record the roof before it is stripped: peg or machine-made tiles, Welsh slate, lead on dormers and porches, eaves and bargeboard details, and the state of each chimney stack. Sound tiles are set aside for reuse and any new covering is matched in type and pitch. Where a rooflight or dormer is wanted, the consent route for the address is settled before the drawings are finished.

Barnet: Mill Hill Conservation Area Character Appraisal Statement, adopted April 2008 (PDF)

Windows, doors and wall finishes

Each sash and casement is surveyed frame by frame, then repaired, eased and draught-proofed or remade to match, keeping the pane pattern that window has. Lime render and weatherboard are repaired in like materials rather than patched with cement. Front doors, porches, gates and fences are treated as part of the elevation, because the appraisal counts changes to them among those that detract from the houses.

Barnet: Mill Hill Conservation Area Character Appraisal Statement, adopted April 2008 (PDF)

Heating, insulation and services

Heating, wiring, plumbing and insulation are planned together, with routes chosen so that historic timbers are not cut. In a listed house, any insulation or new equipment is drawn and justified before it is fitted. Outside equipment such as a heat pump, solar panels or an oil tank is placed only once the consent route for the address is known, since each may need its own application here.

How we work

How we run a Mill Hill 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 Mill Hill. 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. Photograph every elevation

    Send photographs of each side of the house, the roof and the front boundary, with close-ups of windows, doors, porches and any render or weatherboard. Say which details you believe are original and which came later; that comparison shapes the repair list.

  2. Share what you know about the house

    Tell us whether the house is listed, locally listed or covered by an Article 4 direction, if you know, and send copies of past planning or listed building decisions, building control certificates and tree notices. Missing papers are fine; we check the records at the start.

  3. Rank the outside changes

    List the outside changes you hope for, such as a dormer, rooflights, a heat pump, solar panels or a new gate, in order of importance. Several may need consent here, so knowing which matter most lets the design and any applications start in the right place.

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 Mill Hill: questions

Has Barnet approved a rear dormer in Winterstoke Gardens?

In 2023 Barnet approved, subject to conditions, a householder application at a house in Winterstoke Gardens for a single-storey side and rear extension and a roof extension with a rear dormer, a rear rooflight and a side rooflight. That is one decision on one house, not a rule for the street. Winterstoke Gardens appears in the 1991 schedule of the Article 4 directions, so ask Barnet what the order means for your address before a dormer is drawn.

Barnet planning register: public access search (planning, building control and licensing) · Barnet: Article 4 directions in the Mill Hill Conservation Area, 1970 to 1991 (scanned PDF)

Can I fit an air source heat pump at a Mill Hill house?

Possibly, depending on the address. In 2025 Barnet approved, subject to conditions, a householder application at another house in Winterstoke Gardens that placed an air source heat pump at the rear of the garden, alongside a rebuilt rear infill extension with a green roof. It shows one place where the council accepted a heat pump through an application, not that every house can have one. Ask Barnet what your address needs before you choose where the unit goes.

Barnet planning register: public access search (planning, building control and licensing)

Can a listed house in Mill Hill have solar panels?

Barnet has agreed it on one. In 2025 it granted householder permission and listed building consent, subject to conditions, for solar panels on the main roof of a listed house in the Mill Hill Conservation Area, with the battery inside an existing exterior cupboard. Its Local Plan says energy-efficiency proposals for listed buildings must show clearly that they will not harm the building’s special interest, so expect to justify the panel layout, fixings and cable routes.

Barnet planning register: public access search (planning, building control and licensing) · Barnet Local Plan 2021–2036, adopted 4 March 2025: the plan and its adoption documents

Can I pave the front garden for parking?

Expect resistance. The 2008 appraisal names the removal of front boundaries and hard-surfaced frontages for cars among the most notable problems in Nan Clarks Lane and on Highwood Hill. Barnet’s Local Plan says that in conservation areas, proposals losing garden space, such as turning a front garden into hardstanding, will be refused where they harm the area’s character and appearance. The older Article 4 directions also cover hardstandings in the parts they name.

Barnet: Mill Hill Conservation Area Character Appraisal Statement, adopted April 2008 (PDF) · Barnet Local Plan 2021–2036, adopted 4 March 2025: the plan and its adoption documents · Barnet: Article 4 directions in the Mill Hill Conservation Area, 1970 to 1991 (scanned PDF)

What if my house is outside the conservation area?

If it is also not listed or locally listed, Part 4 of Barnet’s 2026 design guidance, on residential extensions and alterations, comes into play: Barnet treats it as a material consideration where planning permission is required to alter or extend a home, and applies it to prior approval cases too. By its own terms it is not meant for homes in conservation areas or for nationally or locally listed buildings, although Barnet allows that it may be pertinent to them in certain instances. Check the boundary map for your address first.

Barnet Sustainable Design and Development Guidance SPD, adopted 15 June 2026: Part 4, guidance on residential extensions and alterations (not intended for conservation areas or nationally or locally listed buildings) · Barnet: Mill Hill conservation area boundary map, November 2023 (PDF)

How much does a house refurbishment cost in Mill Hill?

It depends on scope. In Mill Hill, 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 Mill Hill house

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

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

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