Planning documents for an HMO conversion from a house
Class L permits the change from a house to a small shared house, so everything turns on whether an Article 4 direction applies. The concentration test, room size standards, parking stress evidence and the plans an officer expects.
Converting a family house to a small shared house for three to six people is a change from Class C3 to Class C4, and in most of England it needs no planning application at all. Class L in Part 3 of Schedule 2 to the General Permitted Development Order 2015 permits the change in both directions. The whole question for a landlord is whether an Article 4 direction has removed that right where the property sits, because if it has, the document pack goes from nothing to a full change of use application.
So the first task is not drawing plans. It is establishing the policy position for that street.
Whether an Article 4 direction removes the permitted change
Article 4 directions withdrawing the C3 to C4 right are in force across large parts of many university and hospital towns, sometimes borough-wide and sometimes confined to named wards or a radius around a campus. They are made by the local planning authority, must be published, and take effect from a stated date.
Check three sources and reconcile them:
- the authority's own list of Article 4 directions, with the direction document and its map
- the national Article 4 dataset on planning.data.gov.uk, which carries boundaries for many authorities
- the authority's local plan or HMO supplementary planning document, which usually explains the policy the direction supports
Boundaries are drawn to a line on a map, and properties on the edge of a direction area get misread regularly. Where the position is unclear, ask the authority in writing and keep the reply. Where a direction applies, the change of use needs planning permission, and the policy test is normally a concentration threshold: the proportion of HMOs within a stated radius, often expressed as a percentage of residential properties within 50 m or 100 m.
That threshold decides most applications before any other issue is reached. Get the authority's own HMO data for the radius if it publishes it, and if the proportion is already over the threshold, reconsider the scheme rather than spending on reports.
Room sizes and amenity standards
Two separate sets of standards apply, and landlords conflate them constantly.
Licensing room sizes are set nationally for mandatory licences: 6.51 m² for a room slept in by one person aged over ten, 10.22 m² for two persons, and 4.64 m² where the occupier is a child under ten. Those are floors, not targets, and they are housing law rather than planning.
Planning amenity standards come from the local plan or a supplementary planning document, and they are usually more demanding. They commonly cover minimum bedroom sizes above the licensing figures, minimum communal living space per occupier, the ratio of bathrooms and kitchens to occupiers, and whether a usable garden or external amenity space is retained.
Take the planning standards from the adopted documents for that authority and set them out in a table in the application, with your proposed figures alongside. An officer who can see compliance at a glance has no reason to ask for more drawings.
Refuse and recycling storage
This is the commonest reason a small HMO application is refused, and it is the easiest to solve on paper. Six occupiers generate more waste than a family of four and tend to miss collection days.
Show a dedicated bin store within the curtilage, sized for the authority's actual container set, screened, hard-surfaced, with level access to the collection point and a stated pull distance. Where the property has no rear access, show how bins move to the kerb without crossing a neighbour's land.
Check the authority's own container sizes and collection arrangements rather than drawing a generic store. The numbers differ between authorities and so do the bin dimensions.
Cycle parking and car parking stress
Cycle storage is expected and costs little to provide: a secure, covered store within the curtilage for at least one cycle per bedroom is a defensible position in most authorities.
Car parking is the contested one. Where the authority's standards suggest a shortfall, or where neighbours object about on-street parking, the evidence that answers it is a Parking Survey carried out to a recognised methodology. The approach most authorities accept is the one developed in Lambeth: measure parked vehicles against available legal kerb space within a defined radius of the site, typically 200 m, overnight when residential demand peaks, on at least one weekday night and one weekend night, outside school holidays.
The output is a parking stress percentage. Occupancy approaching or above 85 per cent is generally treated as saturation, and a survey showing stress well below that undermines an objection far more effectively than an assertion that occupiers are unlikely to own cars.
Survey timing is the thing to get right. A count taken at 6pm on a Tuesday measures the wrong population, and a count taken in August in a student area measures an empty street.
Noise and the management plan
Shared houses generate complaints about comings and goings, music and garden use rather than about plant. Where the authority raises noise, the answer is usually a management plan rather than a Noise Impact Assessment, although an assessment is worth commissioning where the property adjoins a particularly sensitive neighbour or where the local plan requires one.
A management plan that carries weight names the manager, sets out the complaints procedure and response times, covers refuse management, garden and outdoor use, quiet hours, parking arrangements for occupiers and visitors, and the tenancy terms that make those obligations enforceable. Offer it as a document the authority can secure by condition.
Internal sound insulation is a Building Regulations matter. A material change of use to an HMO brings Approved Document E into play for separating walls and floors, and doing that work properly also reduces the complaints that lead to enforcement interest later.
Fire separation and escape
Fire safety for a small HMO is dealt with under the Building Regulations and the housing legislation rather than through planning. The usual package is interlinked mains-powered smoke detection throughout, fire doors to risk rooms, a protected escape route, and emergency lighting where the layout requires it.
The housing authority will assess this at licensing or on inspection, applying the fire safety guidance produced for the housing enforcement sector. Plan the work alongside the conversion rather than after it, because retro-fitting a protected stair enclosure once rooms are let is disruptive and expensive.
Licensing alongside planning
Planning permission and an HMO licence are separate consents with different triggers, and holding one gives no entitlement to the other.
| Consent | Trigger | Authority |
|---|---|---|
| Planning permission for C3 to C4 | Only where an Article 4 direction removes the Class L right | Local planning authority |
| Mandatory HMO licence | Five or more occupiers forming two or more households | Housing authority |
| Additional licensing | Smaller HMOs where the authority has designated a scheme | Housing authority |
| Selective licensing | All private rentals in a designated area | Housing authority |
A licence granted for a property with no planning permission does not make the use lawful in planning terms, and authorities do share data between housing and planning teams. Where the use has run unchallenged for a long period, the position on immunity is a separate question worth taking advice on before applying for anything.
Where the proposal is for seven or more occupiers, the use becomes sui generis rather than C4, permitted development does not apply anywhere, and the evidence base is larger, as our note on reports for a large HMO of seven or more people sets out.
What the application must show on plan
For an application in an Article 4 area, the drawings do most of the persuading:
- Existing and proposed floor plans at a stated scale, with every room labelled by use and its floor area given in m².
- A schedule of occupiers against room sizes, communal space and sanitary provision, compared against the authority's standards.
- A site plan showing the bin store, cycle store, any parking and the route to the collection point.
- Retained external amenity space, dimensioned.
- Elevations where any external alteration is proposed, including new rooflights or a rear extension.
- A short Planning Statement addressing the concentration policy, amenity standards, refuse, parking and management.
Label the drawings clearly and keep the room areas consistent between the plans and the schedule. Discrepancies between the two are the fastest route to a request for revised drawings and a lost month.
Fees are indexed annually, so take the current figure for a change of use application from the published schedule rather than from a previous submission.
Enter your postcode on PlanScope to see which reports your site needs. 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.
Frequently asked questions
Do I need planning permission to convert a house to a small HMO?
Not unless an Article 4 direction has removed the permitted change. Class L in Part 3 of Schedule 2 to the General Permitted Development Order 2015 allows movement between Class C3 and Class C4 in both directions. Article 4 directions withdrawing that right cover large parts of many university and hospital towns, so check the authority list and map first.
What is a concentration threshold?
A local plan or supplementary planning document test limiting the proportion of houses in multiple occupation within a stated radius of the application property, commonly 50 m or 100 m. Where the proportion already exceeds the threshold, refusal is likely regardless of the quality of the scheme, so check the authority data before commissioning reports.
What are the minimum bedroom sizes in an HMO?
For mandatory licensing the national floors are 6.51 m² for a room slept in by one person over ten, 10.22 m² for two persons and 4.64 m² for a child under ten. Planning amenity standards set by the local plan are usually more demanding, and both apply independently of each other.
How is a parking survey for an HMO carried out?
By counting parked vehicles against available legal kerb space within a defined radius, typically 200 m, overnight when residential demand peaks, on at least one weekday night and one weekend night, outside school holidays. The output is a stress percentage, and occupancy approaching 85 per cent is generally treated as saturation.
Does an HMO licence make the use lawful for planning?
No. A licence from the housing authority and planning permission are separate consents with different triggers, and holding a licence gives no planning entitlement. Housing and planning teams share data, so an unlicensed planning breach is not hidden by holding a licence or the reverse.
What changes at seven occupiers?
A house shared by seven or more people falls outside Class C4 and becomes a sui generis use. Permitted development rights do not apply anywhere in the country for that change, so planning permission is always needed and the supporting evidence base is larger, typically including parking, refuse, amenity and management material.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.