Turning a property into a shared house can open up a different rental strategy, but the planning rules need to be clear before you move ahead. A C4 HMO usually covers three to six unrelated people sharing a property, but the rules around planning permission and licensing can be easy to confuse.
For landlords, the important questions are whether the property can be used as a C4 HMO, whether an Article 4 Direction affects it, and whether an HMO licence is required. Getting these points right early can help you avoid costly problems later.
What Is a C4 HMO?
A C4 HMO is a small House in Multiple Occupation used by three to six unrelated people who share facilities such as a kitchen or bathroom.
In London, HMOs for multiple people fall within Use Class C4. HMOs with more than six people are generally classed as Sui Generis instead.
This distinction matters because moving from a normal home to a C4 HMO can involve different planning requirements.
| Property use | Typical occupation | Planning use |
| Family home | One household | C3 |
| Small shared HMO | 3 – 6 unrelated people | C4 |
| Larger HMO | More than 6 people | Sui Generis |
If you are considering a larger HMO, it is important to check the planning position before assuming the C4 rules apply.
Does a C4 HMO Need Planning Permission?
A change from a C3 dwelling to a C4 HMO can benefit from permitted development rights. However, an Article 4 Direction can remove those rights in a particular area. In that situation, you may need to apply for planning permission before changing the property’s use.
An Article 4 Direction can apply to all or part of an area and removes specified development rights. The London Plan also recognises that boroughs may use Article 4 Directions to control changes between C3 and C4.
For a landlord, the practical step is simple: check the relevant council’s current planning information before buying or converting a property.
How Does Article 4 Affect a C4 HMO?
Article 4 does not automatically mean that C4 HMOs are banned. Instead, it can remove the permitted development route that would otherwise allow a C3 property to change to C4 without a planning application.
This can make a significant difference when assessing an HMO investment. If Article 4 applies to your property, you may need planning permission and the council will assess the proposed use against its planning policies.
London does not have one single Article 4 position covering every property. Directions can apply to specific boroughs or areas, so always check the current position for the property you are considering.
C4 HMO Planning Permission vs HMO Licensing
Planning permission and an HMO licence are not the same thing. Planning deals with whether the property can lawfully be used for a particular purpose. HMO licensing deals with the management and standards of a property where licensing requirements apply.
For example, mandatory HMO licensing generally applies to properties occupied by five or more people from more than one household who share facilities. Local councils can also have additional licensing schemes, so a smaller C4 HMO may still require a licence depending on where it is located.
What Should You Check Before Buying a C4 HMO?
Buying an existing HMO or converting a property? Check the planning position before you commit to the investment.
Start by checking:
- Whether the property is currently C3, C4, or another use
- Whether an Article 4 Direction applies
- Whether planning permission has already been granted
- Whether there is evidence of an established lawful use
- Whether an HMO licence is required
- Whether additional or selective licensing applies locally
- How many occupants the planning position allows
- Whether there are planning conditions attached to the property
This due diligence can help you avoid buying a property based on an assumed HMO use that cannot be operated in the way you expected.
What If You Want More Than Six Occupants?
A C4 HMO is generally limited to three to six people. If you want to operate an HMO for more than six people, it will generally fall outside Use Class C4 and be treated as Sui Generis.
The planning requirements can therefore be different, which is why you should establish the intended number of occupants before deciding on a property or conversion. If you are considering a larger HMO, see our guide to Sui Generis HMO planning for more information.
Need Help With Your C4 HMO?
HMO Property London specialises in HMO services across London, including HMO planning permissions, licensing, inspections, fire doors, lettings, sourcing and management. The company states that it has more than 10 years of experience and over 1,000 successful HMO stories.
Its existing client feedback also highlights support with HMO planning permissions and compliance, alongside tenant sourcing and property management.
If you are considering a C4 HMO, getting the planning and compliance position checked before you invest can help you make a more informed decision.