What changes in the report pack at ten dwellings

Nine dwellings is a minor application. Ten is major development, and the ten dwelling major threshold documents change in three ways at once: more reports, a longer determination period, and a publicity regime that brings a wider audience to the application.

The trigger is more than the unit count alone. Major development also means a site of 0.5 hectares or more where the number of dwellings is not known, 1,000 m² of floorspace, or a site of one hectare or more. A scheme of eight houses on a large field can be major on area alone.

The definition of major development and why ten matters

The definition sits in the Development Management Procedure Order, and it drives a series of procedural consequences rather than a single policy test.

Thirteen weeks to determine rather than eight. A statutory publicity regime that requires a site notice and a newspaper advertisement rather than neighbour letters alone. Consultation with the lead local flood authority on surface water drainage. And, in national policy, the threshold at which affordable housing is normally sought.

Note the exception. In designated rural areas, including National Parks and National Landscapes, authorities may set an affordable housing threshold as low as five units, so the ten unit line is not universal.

Affordable housing and the policy trigger

This is the single biggest change in the report pack.

At ten units the scheme will normally carry an affordable housing requirement set by the local plan, expressed as a percentage with a tenure split. The application has to show the units, their tenure, their distribution through the scheme, and their specification relative to the market units.

An Affordable Housing Statement setting out the policy requirement, the proposed provision and the mechanism for securing it is the document that answers this. Where the scheme cannot deliver policy-compliant provision, a viability case is needed instead, prepared to recognised professional standards and capable of being published.

Budget for the section 106 agreement too. Affordable housing is secured by obligation, and the legal work on both sides takes weeks.

Publicity, consultation and the longer determination period

Thirteen weeks sounds generous until the consultation responses arrive at week nine.

The newspaper advertisement and site notice bring objectors who would never have received a neighbour letter, and parish councils treat major applications differently from minor ones. Expect a longer list of representations and expect the case officer to want a written response to the themes rather than to each letter.

Where the council's policy requires it, or the scheme is locally contentious, pre-application community engagement becomes worth doing. A Statement of Community Involvement records who was consulted, what was said and what changed in response. It is not required on every major scheme, and PlanScope's own recommendation engine flags it at larger unit counts, with the council's validation list taking precedence over any general rule.

Committee is also more likely. Many authorities have a scheme of delegation that sends major applications to committee automatically or on a small number of objections.

That changes what the documents have to do. A committee report is written for members who have not read the application, so the officer will summarise your case in a few paragraphs. Documents that state the argument clearly in their opening pages get summarised accurately, and documents that bury it do not. Write the first page of the planning statement as though it will be the only page anyone reads.

Transport evidence expected at this scale

Ten dwellings generates modest traffic, and the highway authority will still want the work done properly.

A Transport Statement covering trip generation, access geometry, visibility, parking provision against the local standard, cycle parking and refuse vehicle access is usually proportionate at this scale. A full Transport Assessment with junction modelling belongs to larger schemes, and PlanScope's detector flags one at higher unit and floorspace thresholds, though a local highway authority can ask for more where the access or the network warrants it.

Travel plans appear at this scale in some authorities, usually as a condition rather than a submission requirement. Ask at pre-application.

Drainage and the lead local flood authority role

At major status the lead local flood authority becomes a statutory consultee on surface water drainage, and that changes the level of detail expected.

A concept drawing is no longer enough. Expect to provide infiltration testing results, a drainage layout with pipe sizes and gradients, calculations demonstrating that runoff is restricted to the agreed rate for the design return period with a climate change allowance, an assessment of exceedance flow routes, and a maintenance schedule naming who is responsible for each element in perpetuity.

A Drainage Strategy carrying all of that, with the calculations appended, is what the drainage engineer wants. Allow time: lead local flood authority responses are frequently the last consultation to arrive.

Ecology and biodiversity gain reporting

Mandatory biodiversity net gain applied to major development from February 2024 and to small sites from April 2024, so the requirement exists either side of the line. What changes is the scale of the baseline exercise.

A larger site carries more habitat parcels, more condition assessment and, more often, a shortfall that cannot be made up on site. Where off-site units or statutory credits are needed, that has to be identified early because securing off-site provision takes time and the biodiversity gain plan cannot be approved without it.

The statutory metric has to be completed by a competent person under the Environment Act 2021 framework. PlanScope can draft the assessment structure and the policy framing, and the metric calculation and the ecological judgement behind it belong to a qualified ecologist.

Environmental impact assessment is a separate question and is not triggered by ten units. The screening thresholds for residential development in the 2017 Regulations sit well above this scale, though a site in a sensitive area can be caught regardless of size.

The documents added between nine and ten units

For a scheme moving from nine units to ten on the same site, expect to add:

• An Affordable Housing Statement, and a viability assessment if policy provision is not proposed
• A Design and Access Statement, which is mandatory for major development
• A fuller drainage strategy with calculations, exceedance routing and a maintenance plan
• A more developed biodiversity net gain assessment, with an off-site strategy if needed
• A heads of terms for the section 106 agreement, and the legal programme to complete it
• A response to the wider consultation that the major publicity regime produces

Phasing is worth thinking about before the application is drafted. Where a site will be built in phases, conditions requiring drainage, landscape and ecology details can be drafted phase by phase, and an applicant who does not ask for that ends up discharging conditions for the whole site before starting the first plot.

Everything that applied at nine units still applies. The smaller scale version of this document pack is set out in the guide to backland development of two houses, and the intermediate position is covered in the article on five dwellings on a village edge.

Fees change at this line too. The application fee is calculated per dwelling on a banded scale, and the pre-application advice charged by most authorities steps up for major schemes. Neither is large next to the consultant costs, and both belong in the appraisal.

Programme is the item most often underestimated. Thirteen weeks is the statutory period, and on a scheme with affordable housing the section 106 agreement usually takes longer than the determination itself, so the practical answer is an agreed extension of time and a legal timetable running in parallel with the consultation.

One planning point worth making plainly. Reducing a scheme from ten units to nine to avoid major status is a recognised move, and officers recognise it too. Where the site is capable of more, a reduction that leaves the remainder of the site undevelopable will be treated as what it is.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.