Small HMOs: 3–6 occupiers
Small shared houses occupied by three to six unrelated people will generally fall within Use Class C4. A change from C3 may be permitted development unless an Article 4 Direction or another restriction applies.
HMO architecture · planning · technical design
Specialist HMO architects for property owners and investors.
Planning-led HMO feasibility, conversion design and Building Regulations support for C4, sui generis and existing HMO properties.
We assess the planning route, occupancy potential, space standards, amenity and fire-safety implications before the layout is fixed or substantial costs are committed.
Before you purchase or convert
Understand the approval route before committing capital.
A workable HMO is not simply a house with additional bedrooms. The planning position, licensing regime, local room standards, shared amenity, escape strategy and physical constraints should be considered together.
- Article 4 and permitted development checks
- C4 or sui generis use assessment
- Indicative occupancy and layout testing
- Local HMO policy and concentration review
- Fire-safety and escape-route appraisal
- Refuse, cycle and parking requirements
HMO project types
Support for small, large and existing HMOs.
Larger HMOs: 7+ occupiers
An HMO occupied by more than six people will generally be treated as sui generis. Planning permission is normally required and the application may need to address concentration, amenity, parking, refuse, noise and local housing policy.
Existing and retrospective HMOs
Where a property is already operating as an HMO, we can review the planning history, evidence of use, existing layout and possible routes including planning permission or a lawful development application.
Separate approval regimes
Planning, licensing and Building Regulations are not the same.
A successful HMO strategy should identify every relevant approval and avoid assuming that one consent automatically resolves the others.
Planning
We review the existing lawful use, proposed occupancy, Article 4 status, local HMO policies, planning history and the likely application route.
HMO licensing
Licensing is separate from planning. We can review the layout against published local standards and prepare architectural information, while the council remains responsible for the licensing decision.
Building Regulations
Material changes of use and associated building work can trigger requirements relating to fire safety, structure, sound insulation, ventilation, drainage, thermal performance and accessibility.
Fire strategy
Escape routes, fire doors, compartmentation, alarms, emergency lighting and higher-risk layouts should be considered before the room arrangement is fixed.
National reference material is available from Planning Portal and GOV.UK. Local council requirements must also be checked.
Common project risks
Issues worth resolving before the design is finalised.
Buying before checking the planning route
A property may appear capable of accommodating the intended rooms but still face Article 4 restrictions, local concentration policies, parking constraints or previous planning conditions.
Designing only around bedroom count
Overcrowded layouts can weaken planning applications, reduce tenant amenity and create problems with circulation, shared space, ventilation and management.
Leaving fire safety until technical design
The escape route, stair arrangement, inner rooms, cooking facilities and storey heights can materially affect whether the proposed layout is workable.
Treating one approval as covering everything
Planning permission, HMO licensing, Building Regulations and landlord safety duties are separate. Securing one does not automatically satisfy the others.
Our HMO process
A structured route from feasibility to technical design.
Property and planning review
We review the address, existing use, planning history, Article 4 controls, local standards and your intended occupancy.
Feasibility layout
The property is tested for compliant bedrooms, communal areas, kitchens, bathrooms, circulation, refuse, cycles and fire escape.
Planning strategy
We identify whether the proposal is C4, sui generis, permitted development, a full planning application or potentially a lawful existing use.
Planning submission
Where required, we prepare the drawings, schedules and supporting planning case and coordinate proportionate specialist information.
Technical design
Following the agreed planning route, the design can be developed into a coordinated Building Regulations package.
Building Control support
We issue the architectural information and respond to reasonable Building Control queries within the agreed appointment.
Typical HMO deliverables
Architectural information tailored to the property and route.
The exact scope is confirmed in a written fee proposal. Planning, technical design and specialist consultant requirements can be appointed in defined stages.
Pre-purchase HMO feasibility review
Planning and Article 4 assessment
Existing and proposed floor plans
Bedroom and amenity-space schedule
C3 to C4 planning applications
Sui generis HMO planning applications
Planning Statements and Design and Access Statements
Lawful development application drawings
Refuse, cycle and parking layouts
Fire-safety layout coordination
Building Regulations drawings
Structural and specialist consultant coordination
HMO questions
Frequently asked questions about HMO conversions.
Does a six-person HMO need planning permission?
A property occupied by three to six unrelated individuals sharing facilities will generally fall within Use Class C4. A change from a C3 dwelling to C4 may be permitted development, but an Article 4 Direction, planning condition, previous use or local circumstances can mean that planning permission is required.
When does an HMO become sui generis?
An HMO occupied by more than six residents will generally fall outside Class C4 and be treated as sui generis. A material change of use to a larger HMO normally requires planning permission.
Is HMO licensing the same as planning permission?
No. Planning controls the use and development of the property, while licensing regulates how the HMO is operated and whether it meets the relevant housing standards. Both may be required.
Do all five-person HMOs need a licence?
Mandatory licensing generally applies where at least five people from more than one household occupy the HMO and share facilities. Councils may also operate additional licensing schemes that cover smaller HMOs.
Can Hepburn Architects assess a property before purchase?
Yes. A pre-purchase feasibility review can identify the likely planning route, Article 4 position, indicative occupancy, layout constraints and specialist information likely to be required.
Can every HMO bedroom have an ensuite?
Not necessarily. Ensuites can improve privacy, but they must not compromise bedroom sizes, shared amenity, ventilation, drainage, circulation or fire safety.
Can you help with an existing unauthorised HMO?
Yes. We can review the planning history, available evidence, existing layout and length of use before advising on possible planning or lawful development routes. Each case depends on its evidence and circumstances.
Do you provide Building Regulations drawings for HMOs?
Yes. We can prepare coordinated architectural drawings addressing the relevant technical requirements and integrate structural and specialist information where required.
Assess the property
Considering an HMO purchase or conversion?
Discuss the proposed occupancy, planning route and property constraints directly with Hepburn Architects before committing to the scheme.