House Extensions · HA5 Pinner
Harrow protects the Pinner Village, Eastcote Village and Pinnerwood conservation areas, with their historic cores and timber-framed survivors, alongside metro-land householder control across the rest of HA5.
Working across the whole borough rather than just this area? See house extensions in Hillingdon.
House extensions in Pinner are dominated by single-storey rear and side-return additions on HA5's inter-war metro-land semis and detached houses around, with double-storey and wrap-around schemes where the plot allows. Hillingdon Council weighs depth, height and neighbour daylight; many extensions across Pinner, Eastcote, Hatch End fringe, Pinner Green are Permitted Development, which we confirm with a Lawful Development Certificate before you build.
The whole spectrum — rear extensions, side returns, wraparounds, double-storey, basement digs. Planning-led design with detailed technical phase, ideal for inter-war metro-land semis and detached houses around typical of Pinner.
Across Pinner, Eastcote, Hatch End fringe, Pinner Green in HA5, the dominant property is inter-war metro-land semis and detached houses around pinner and eastcote, with the historic pinner village core. That stock shapes what house extension drawings looks like here: the right approach for a period terrace differs from a mansion-block flat or a new-build, and Hillingdon Council judges each on design quality and neighbour impact. We survey the specific Pinner property, confirm the planning route — Permitted Development, a Lawful Development Certificate, or full planning — and draw a council-ready set tailored to the HA5 streetscape.
Housing stock in HA5: Inter-war metro-land semis and detached houses around Pinner and Eastcote, with the historic Pinner village core.
Within the district: Pinner, Eastcote, Hatch End fringe, Pinner Green.
Streets we know in HA5: the streets around Pinner High Street and the parish church, the Eastcote village roads and the metro-land estates toward Pinner Green. Each road has its own building line, boundary treatment and precedent that Hillingdon Council weighs when assessing a house extension drawings scheme.
Conservation areas: Pinner Village, Eastcote Village, Pinnerwood. Inside these, most external work needs full planning and a Heritage Statement.
Getting around HA5: Pinner and Eastcote on the Metropolitan line, plus Hatch End Overground nearby.
Property values: the mean HA5 sale in 2025, £739,876, ran above the median of £702,500, which is what happens when a handful of expensive houses sit at the top of the range. Both come from HM Land Registry, covering 438 transactions.
Borough character: Largest outer west London borough; significant Green Belt; Heathrow noise contours affect planning decisions in Harmondsworth and Sipson.
Measured existing survey, photographic record, Article 4 and conservation check specific to Pinner before we quote.
2–3 design options at concept stage — alternative layouts, glazing, roof forms.
Site location plan, existing and proposed plans, elevations, sections, D&AS where required.
Part L thermal, Part B fire, Part M accessibility, structural strategy.
Steel beam, foundation, lintel design. Chartered engineer sign-off.
Party Wall notices where needed; Thames Water Build Over Agreement where within 3m of a public sewer.
Single planning or building-regs submission.
Planning + building regs + structural.
Listed, conservation or complex sites.
Yes. The metro-land semis and detached houses suit rear, side and wrap-around extensions and loft conversions. Within the Pinner Village, Eastcote Village or Pinnerwood conservation areas changes need full planning with a Heritage Statement; outside them, much runs on the Permitted Development route, confirmed with a Lawful Development Certificate. We confirm which applies to your road.
The Pinner Village conservation area protects the historic High Street, the medieval parish church and the timber-framed survivors, so external changes there are carefully assessed on materials and character. We design sympathetically and handle the Harrow application with a Heritage Statement.
Usually yes on the metro-land semis outside the conservation areas — a hip-to-gable plus rear dormer within the volume allowance, confirmed by a Lawful Development Certificate. The 1930s roofs generally give good head height. Inside the village designations, roof changes need full planning. We confirm which applies.
With HA5 houses around £575,000-£1m and a direct Metropolitan line into the City and West End, a rear or loft extension adds family space worth above the build and drawing cost. Pinner's village character is highly sought after.
Hillingdon Council charges its own statutory application fee (currently £548 for a householder planning application, £610 for a full application). We quote the drawings as one fixed price and the free site survey covers every HA5 address.
For a HA5 project across Pinner, Eastcote, Hatch End fringe, Pinner Green, expect roughly 3–4 weeks from instruction to submission: week 1 the measured survey, weeks 2–3 the drawings and your revisions, then validation and the statutory determination by Hillingdon Council (8 weeks for a householder application). We carry the Pinner application through every officer query to the decision.
Pinner (HA5) sits primarily in Hillingdon, so applications are decided by Hillingdon Council. Conservation areas within HA5 include Pinner Village, Eastcote Village, Pinnerwood, where full planning and a Heritage Statement are required. We confirm the planning route for your exact address before quoting.
Almost always. Any structural work behind house extension drawings in Pinner — new openings, steel beams, loft floors, foundations — needs Building Regulations approval covering structure (Part A), fire escape (Part B) and insulation (Part L), submitted to Hillingdon Council Building Control or an approved inspector. On HA5's typically terraced and semi-detached stock, a Party Wall notice to adjoining neighbours is normally required before the steelwork. We coordinate both as part of the Complete package.
In value terms, yes. The bigger risk is an unapproved or non-compliant scheme — which is why council-ready drawings and a clean Building Control sign-off matter on HA5 homes.
Pick a slot that suits you. No obligation and no sales pressure, just straight answers on your planning route.
Every HA5 postcode district we draw in, the stock that dominates it and the authority that validates a house extension there. HA5 fees below are the statutory England rates for 2026, not house extension estimates.
| Postcode | Area | Dominant stock | What it means for a house extension |
|---|---|---|---|
| HA5 | Pinner / Eastcote | Tudor fragments, Edwardian villas, 1930s semi-detached | A house extension in Pinner / Eastcote may land with Hillingdon Council or Harrow Council — HA5 crosses the boundary, and the HA5 policies map decides it street by street. |
| HA5 | Eastcote | 1930s semi-detached | Eastcote sits inside HA5; house extension proposals here are determined by Hillingdon Council. |
| HA5 | Pinner | Tudor fragments, Edwardian villas, 1930s semi-detached | Pinner sits inside HA5; house extension proposals here are determined by Harrow Council. |
| HA4 | Ruislip | 1930s semi-detached, Tudor cottages | Adjoining district to HA5, also inside Hillingdon for house extension purposes. |
| HA6 | Northwood | 1930s detached, Edwardian villas | Adjoining district to HA5, also inside Hillingdon for house extension purposes. |
| UB3 | Hayes / Harlington | 1930s semi-detached, post-war estates | Adjoining district to HA5, also inside Hillingdon for house extension purposes. |
| HA1 | Harrow / Harrow on the Hill | Georgian and Victorian houses, listed buildings | Adjoining district to HA5, also inside Harrow for house extension purposes. |
| HA2 | North Harrow / South Harrow | 1930s semi-detached | Adjoining district to HA5, also inside Harrow for house extension purposes. |
| HA3 | Harrow Weald / Kenton / Wealdstone | 1930s semi-detached | Adjoining district to HA5, also inside Harrow for house extension purposes. |
| HA7 | Stanmore | 1930s semi-detached, Edwardian villas | Adjoining district to HA5, also inside Harrow for house extension purposes. |
Roof pitch, wall build-up and plot depth change every few HA5 streets, and each one changes what a house extension can achieve at that address.
HA5 (Pinner / Eastcote) conservation designations: there are 29 across Hillingdon Council, Harefield, Ickenham, Uxbridge among them. Designation costs a HA5 (Pinner / Eastcote) owner the permitted-development route: a house extension then needs a £548 householder application over 8 weeks, in place of the £249 prior approval route that takes 6 weeks. Ruislip Village is the HA5 (Pinner / Eastcote) designation that most often changes a house extension design.
HA5 (Pinner / Eastcote) permitted development status: there is no borough-wide direction from Hillingdon Council, so a house extension at a HA5 address is normally still permitted development. We certify that with a £274 Lawful Development Certificate rather than leaving a HA5 (Pinner / Eastcote) sale to argue it later.
HA5 (Pinner / Eastcote) housing stock: 1930s semi-detached dominates; Metropolitan Green Belt covers much of north Hillingdon; Victorian cottages in Uxbridge and Ruislip villages; post-war housing near Heathrow. Largest outer west London borough; significant Green Belt; Heathrow noise contours affect planning decisions in Harmondsworth and Sipson. Read that before choosing a house extension route in HA5 (Pinner / Eastcote) — construction, not postcode, sets what is achievable. Hillingdon Council charges £548 for a householder application and has 8 weeks to determine it.
HA5 (Pinner / Eastcote) conservation designations: there are 29 across Harrow Council, Stanmore, Harrow Weald, Harrow on the Hill among them. Designation costs a HA5 (Pinner / Eastcote) owner the permitted-development route: a house extension then needs a £548 householder application over 8 weeks, in place of the £249 prior approval route that takes 6 weeks. Pinner Village is the HA5 (Pinner / Eastcote) designation that most often changes a house extension design.
HA5 (Pinner / Eastcote) permitted development status: there is no borough-wide direction from Harrow Council, so a house extension at a HA5 address is normally still permitted development. We certify that with a £274 Lawful Development Certificate rather than leaving a HA5 (Pinner / Eastcote) sale to argue it later.
HA5 (Pinner / Eastcote) housing stock: 1930s semi-detached dominates; Edwardian villas in Harrow on the Hill and Pinner; Metropolitan Green Belt in Stanmore and Harrow Weald; post-war flats around Harrow Central. Outer north-west London suburban; Harrow on the Hill has exceptionally strict heritage controls; rest of borough permissive. Read that before choosing a house extension route in HA5 (Pinner / Eastcote) — construction, not postcode, sets what is achievable. Harrow Council charges £548 for a householder application and has 8 weeks to determine it.
Sources for this HA5 house extension page: borough policies maps and conservation-area registers (2025–26), Royal Mail postcode district boundaries, the Town and Country Planning (Fees for Applications) (England) Regulations, the Town and Country Planning (General Permitted Development) (England) Order 2015 as amended, and the Party Wall etc. Act 1996.
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