Half a hectare: the site area route to major status

A three dwelling scheme can be major development. Not because of the houses, but because of the red line. Article 2 of the Development Management Procedure Order 2015 defines major development by unit count and by site area, and the area limbs catch schemes that nobody involved thinks of as major: 0.5 hectares or more where the number of dwellings is not yet known, and one hectare or more for any development whatever it contains.

That second figure is the one that surprises people, because it has nothing to do with how many homes you are building.

The two area limbs

For housing, development is major where 10 or more dwellings are proposed, or where the site is 0.5 hectares or more and it is not yet known whether the scheme will reach 10. The second limb exists for outline applications, where the unit count is a matter for reserved matters.

Separately, any development on a site of one hectare or more is major, regardless of use or unit count. A single agricultural building, a car park, a solar array or four houses set in two hectares of paddock all qualify.

The consequences follow automatically: a 13 week determination period rather than eight, a newspaper advertisement, a longer local validation list and a different fee band. Our note on outline or full application at different scheme scales covers which route suits which site.

How the area is measured

The site area is the area within the red line on the location plan, measured as a plan area rather than a surface area. Sloping ground does not help you.

Measure it properly rather than estimating from a rough boundary. Half a hectare is 5,000 m², which is roughly a square of 71 metres a side. A plot that measures 90 metres by 58 metres is over the line, and on a long narrow site the arithmetic is rarely obvious from the drawing.

Put the area on the location plan and on the application form, and make sure the two agree. A mismatch between the stated area and the measured red line is a validation query, and it delays the clock.

Access strips, verges and land you do not build on

National guidance expects the red line to include all the land needed to carry out the development. That means the access, any visibility splays that are within the applicant's control, land for parking and turning, and land for landscaping and drainage required by the scheme.

A long private drive to a back-land plot is exactly the sort of addition that pushes a site over 0.5 hectares. So is a swale or an attenuation basin placed in a corner of the field, and so is an area of land given over to biodiversity gain habitat.

Land the scheme does not require should stay outside the line. Land in the applicant's ownership or control that is adjacent, but not part of the development, goes inside a blue line instead. That distinction matters for the area calculation, for the fee, and for which ownership certificate you sign.

What you cannot do is draw a tight line around the houses and leave the access out. The application will be invalid, and redrawing it later restarts the determination period.

Outline applications

The 0.5 hectare limb bites hardest at outline stage. If you apply in outline for residential development on 0.6 hectares with the number of units reserved, the application is major, with the longer period and the extra requirements, even if the eventual scheme is six houses.

Two responses. Either state a maximum number of dwellings in the description, bringing the application under the unit limb, which is often the better answer for a small site. Or accept major status and programme for it.

Stating a maximum has a cost: it caps what reserved matters can deliver, and increasing it later needs a fresh application. On a small site that is usually an acceptable trade for a shorter determination period and a shorter document list.

Fees

Fees for outline applications are calculated by site area, in bands, with a cap, so the red line drives the fee directly. Fees for full applications for dwellings are calculated per dwelling, also with a cap, so there the area is irrelevant to the fee even though it decides major status.

That produces an odd result worth knowing: on an outline application a generous red line costs money twice, once in fee and once in programme. Work from the current fee schedule rather than any figure quoted elsewhere, because the rates are indexed annually, and see our note on how planning fees escalate with unit numbers for the shape of the curve.

Requirements triggered by area rather than units

Several technical requirements key off site area, and they catch small schemes on large plots:

1. A flood risk assessment is expected for sites of one hectare or more even in Flood Zone 1, as well as for any site in Flood Zone 2 or 3. A Flood Risk Assessment on a two hectare paddock with three houses is a real requirement, not an officer being difficult.
2. Environmental impact assessment screening for urban development projects keys partly off area, so a larger site needs the screening question answered even with a modest scheme on it.
3. Biodiversity net gain treats small sites differently, and the small site definition includes a site area limb at 0.5 hectares as well as the unit count. Crossing it changes which rules apply to the Biodiversity Net Gain Assessment.
4. Some local plans engage affordable housing policy on sites of 0.5 hectares or more as an alternative to the unit threshold. Read the adopted policy rather than assuming.

Drawing the red line deliberately

Treat the line as a decision, not a drafting task.

Work out what land the development actually needs. Include it. Exclude what it does not need, and put adjacent land you control in blue. Then measure the area, check it against the thresholds, and see whether a different arrangement of the same scheme sits on the other side of one of them.

Sometimes it will, legitimately. Moving an attenuation basin from a corner of the field to within the housing area, or using an existing access rather than forming a new one across a paddock, can take a site under 0.5 hectares without changing a single house. Sometimes it will not, and then you programme for major status from the start.

What you should not do is manipulate the line to exclude land the scheme needs. Officers check whether the access, the parking and the drainage can all be delivered within the line, and an application that cannot is invalid or, worse, permitted and then undeliverable.

An illustrative case: four detached houses on a former orchard, with a 110 metre access drive from the lane. The houses and gardens came to 0.38 hectares. Adding the drive and the visibility splay took the red line to 0.54 hectares, and because the application was in outline it became major development. Reconfigured as a full application with the unit number stated, it was determined as a minor application in nine weeks.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it.

Browse the full set of report types to see what changes once a site crosses into major development.

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