Householder planning permission in Hillingdon: 84.2% pass

How does Hillingdon compare on speed and outcome?

Hillingdon approved 84.2% of the householder applications it decided in the three years to March 2026, slightly above the London average, and settled 93.0% inside eight weeks. It also holds 150 Article 4 areas in the national register, the fifth highest count in London.

Sources: decision figures from MHCLG District Planning Application Statistics (PS1 and PS2), twelve quarters to March 2026; Article 4 areas from the MHCLG Planning Data Platform register, retrieved 1 September 2026, excluding revoked entries; appeals from Planning Inspectorate casework decided 2016–2026. Hillingdon’s median householder appeal took 57 days, the fastest in London.

Planning in Hillingdon — what you need to know

Hillingdon is the only borough in this guide where aircraft noise is a planning consideration in its own right. Around Harmondsworth and Sipson the Heathrow noise contours affect what can be built and what insulation a scheme has to demonstrate, particularly for anything that creates a new bedroom or a new dwelling. It is a constraint that does not appear in any conservation-area map and catches people who only checked the designations.

Largest outer west London borough; significant Green Belt; Heathrow noise contours affect planning decisions in Harmondsworth and Sipson. The borough has a population of approximately 306,000 residents and covers postcodes HA4, HA5, HA6, UB3, UB4, UB7, UB8, UB9, UB10, UB11.

The housing stock in Hillingdon is predominantly 1930s semi-detached dominates; Metropolitan Green Belt covers much of north Hillingdon; Victorian cottages in Uxbridge and Ruislip villages; post-war housing near Heathrow. This mix of property types means that Hillingdon Council deals with a wide range of applications, from rear extensions on terraced houses to loft conversions on semi-detached properties and full refurbishments of period homes in conservation areas.

With 29 designated conservation areas and no current Article 4 Directions,Hillingdon records 150 Article 4 areas and 441 listed buildings alongside its 29 conservation areas (MHCLG planning statistics, retrieved 1 September 2026), and it decides more householder applications than almost any borough in this guide — 3,978. The borough runs from the Victorian and Edwardian streets of Uxbridge out to Green Belt at Harefield and Ickenham, so the constraint that matters is genuinely address-specific rather than borough-wide.

At Architectural Drawings London, we prepare planning drawings and building regulations drawings for properties across all Hillingdon postcodes. Our MCIAT chartered architectural technologists have experience with Hillingdon Council and understand the specific policies, design guides, and precedents that apply in Hillingdon.

Where do Hillingdon’s 150 Article 4 areas apply?

Hillingdon does not currently have any borough-wide Article 4 Directions that restrict Permitted Development rights for standard householder developments such as loft conversions, rear extensions, or outbuildings.

This means that most common home improvements in Hillingdon can proceed under Permitted Development without needing to apply for planning permission, provided they meet the national criteria for size, height, and position. We recommend applying for a Lawful Development Certificate (£274) to formally confirm that your project qualifies as Permitted Development. This provides legal certainty and is valuable when selling the property.

Even without Article 4 Directions, properties in Hillingdon's 29 conservation areas have additional restrictions on permitted development. We check the specific restrictions affecting your property as part of our initial assessment.

How many conservation areas does Hillingdon have?

Hillingdon has 29 designated conservation areas. Notable conservation areas include:

• Uxbridge
• Ruislip Village
• Northwood
• Harefield
• Ickenham

In conservation areas, Permitted Development rights are more restricted than in non-designated areas. Key restrictions include:

• No cladding, stone, artificial stone, pebble dash, render, timber, plastic, or tile to any external wall without planning permission
• No side extensions under Permitted Development
• Rear extensions are limited and may require planning permission
• Dormer loft conversions facing the highway require planning permission
• Satellite dishes on front elevations or chimneys are not permitted
• Demolition of gates, walls, fences, or other boundary treatment requires planning permission

Twenty-nine designated areas, with no Article 4 Direction across the borough, spread among village cores rather than concentrated in one district. The council issued 146 enforcement notices in three years (MHCLG planning statistics, retrieved 1 September 2026), a moderate-to-high figure that reflects the amount of land here rather than any particular strictness. Between designation, Green Belt and the noise contours, Hillingdon has three overlapping constraint maps and an address needs checking against all three.

Popular projects in Hillingdon

Interwar semis across most of the borough, Victorian cottages in the Uxbridge and Ruislip village cores, post-war estates, and Metropolitan Green Belt over much of the north. Hillingdon took 5,698 planning decisions in three years and approved 80.3%, with new-dwelling schemes at 60.0% (MHCLG planning statistics, retrieved 1 September 2026). Both figures are better than the London pattern, which makes this a more accommodating authority than its size and Green Belt coverage might suggest.

Two-storey extensions

The semi-detached and detached housing stock in Hillingdon is well suited to two-storey rear extensions, which almost always require planning permission. A two-storey extension can add a larger kitchen-diner at ground floor and an additional bedroom and bathroom above. Hillingdon Council generally supports two-storey extensions that are subordinate to the original dwelling, set in from the boundary, and do not result in unacceptable loss of light or privacy to neighbours.

How much do planning drawings cost in Hillingdon?

The council charge is standard. What is not standard is the evidence a Hillingdon application may need — a Green Belt case, a noise assessment, or neither, depending entirely on where the property sits. We establish which apply before quoting rather than after. The borough agreed an extension of time on 40.9% of decisions (MHCLG planning statistics, retrieved 1 September 2026), so allow slack on anything beyond a householder application. Our fee is fixed up front, about 30% below the London architect rate.

We include a measured survey, existing and proposed plans, elevations, and a site plan — everything required for a valid planning submission to Hillingdon Council. Our fees are 30% below typical London architect rates for the same scope of work.

A Lawful Development Certificate confirms the planning position and nothing else. Under the Heathrow contours that limitation matters: the certificate says the work was permitted development, not that it meets building regulations. Hillingdon granted 1,756 such certificates in three years (MHCLG planning statistics, retrieved 1 September 2026).

Our experience in Hillingdon

We cover all Hillingdon postcodes: HA4, HA5, HA6, UB3, UB4, UB7, UB8, UB9, UB10, UB11. Whether your property is in a conservation area, affected by an Article 4 Direction, or in an unrestricted residential street, we have experience with Hillingdon Council and understand the borough's planning policies.

Our MCIAT chartered architectural technologists prepare planning drawings and building regulations drawings for residential projects across Hillingdon. We handle the full process from initial measured survey through to planning submission, and we liaise with Hillingdon Council on your behalf.

We also work in Hillingdon's neighbouring boroughs:

What are the odds of approval in Hillingdon?

84.2%of householder applications approved in Hillingdon

3,978householder decisions in three years

93.0%decided within eight weeks

1,756certificates of lawful development issued

Hillingdon sits close to the London average. Of 3,978 householder decisions in the three years to March 2026, 3,351 were approved and 627 refused — 84.2%, against 83.0% London-wide. In practice that means the outcome is decided by the scheme and the drawings rather than by the authority: there is no local bias to plan around, and no local leniency to rely on.

Speed is not the problem here. Hillingdon decided 93.0% of householder applications within the statutory eight weeks. If your project has a fixed start date, the determination period is the predictable part of the programme — the variable is how long the drawings take before submission.

The prior-approval route works here. 63.1% of the 476 larger rear extensions determined in Hillingdon under the neighbour-consultation scheme were granted. If your extension needs the extra depth that scheme allows, this is a borough where it is worth serving the notice rather than defaulting to a full application.

The council also issued 1,756 certificates of lawful development in the same three years. That is the route for work that is already permitted development: it is not a permission, it is proof you did not need one, and it costs £274 against the £548 householder application fee.

Source: MHCLG District Planning Application Statistics (PS1 and PS2), the statutory return every English planning authority files. Figures cover the twelve quarters to March 2026 and are decisions made in that window, not applications submitted. Published under the Open Government Licence v3.0.

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