What is an Article 4 Direction and why does it matter for HMOs?
An Article 4 Direction is a tool a local planning authority uses to switch off specific permitted development rights within a defined area. For HMOs, the most common use is removing the automatic right to convert a family home into a small house in multiple occupation. Where an Article 4 Direction applies, a landlord who wants to create an HMO must first obtain planning permission — they can no longer rely on permitted development. This matters enormously for buy-to-let, because it can be the difference between a straightforward conversion and a full planning application with an uncertain outcome.
How does the C3 to C4 change of use work?
Planning law puts buildings into use classes. An ordinary family home is Use Class C3. A small HMO — shared by three to six unrelated occupants — is Use Class C4. Nationally, there is a permitted development right allowing a change from C3 to C4 without a planning application. So in most of the country, converting a house to a small HMO is a planning matter you can do under permitted development, provided the property otherwise complies. That right is exactly what an Article 4 Direction removes.
What happens in an Article 4 area?
In an area covered by an Article 4 Direction for HMOs, the C3 to C4 permitted development right no longer applies. That means:
- You must submit a full planning application to change the use to a small HMO.
- The council can refuse the application, often to manage the concentration of HMOs in a neighbourhood.
- Some authorities operate policies limiting HMOs to a maximum percentage of properties within a given radius.
- Buying a house expecting to convert it can go wrong if permission is then refused.
Many university cities and towns with strong HMO demand have introduced Article 4 Directions precisely because HMOs cluster there. Always check whether the specific street sits inside an Article 4 area before you commit — a property already trading as an HMO with the correct planning status is worth more, and is easier to finance, than one where the use still has to be established.
What about large, sui generis HMOs?
A large HMO — one occupied by seven or more people sharing facilities — falls outside the standard use classes and is treated as sui generis ("of its own kind"). There is no permitted development route to a sui generis HMO anywhere in the country, so creating one always requires a planning application, regardless of Article 4. This is a common trap: a landlord assumes the C3 to C4 permitted development right covers them, but the moment the property is designed for seven or more sharers, it becomes a full planning matter. Large HMOs also sit with a narrower pool of specialist lenders, as covered in our HMO mortgage guide.
Planning versus licensing: what is the difference?
These two regimes are frequently confused, but they are entirely separate and a property can need both:
- Planning permission determines whether the building can lawfully be used as an HMO in the first place. It is a land-use question handled by the planning department.
- HMO licensing governs how the HMO is run once let — room sizes, fire safety, amenities, and the fit-and-proper status of the manager. It is handled by the council's housing team.
Holding a mandatory HMO licence does not prove the use is lawful in planning terms, and having planning permission does not exempt you from licensing. Getting one but not the other is a common and costly mistake. If you are weighing a self-contained conversion instead, our guide to multi-unit freehold blocks explains an alternative that often avoids HMO licensing altogether.
Why does this matter for HMO finance?
Lenders care deeply about the planning position because it goes to the security. An HMO operating without the correct planning use is, in the lender's eyes, a compliance risk, and valuers may down-value or refuse to value a property whose use has not been established. If you are buying a house to convert in an Article 4 area, most lenders will want to see the planning position resolved, or will fund the purchase and works as a refurbishment project with a clear plan to regularise the use before you move onto a standard HMO mortgage. Getting the planning strategy right first is what keeps the finance on track.
How do you finance an HMO through the planning maze?
Because Article 4, use classes, and licensing all interact, the finance has to reflect the property's real planning status. Assesr packages your HMO deal — the use class, the Article 4 position, the licensing plan, and your experience — into a lender-ready credit paper in around 60 seconds and matches it to specialist buy-to-let finance lenders whose criteria genuinely fit the situation. You pay nothing until completion: just the 0.5% Assesr Fee on drawdown, a quarter of the typical broker fee.
Frequently asked questions
What is an Article 4 Direction?
An Article 4 Direction is a power a local planning authority uses to remove specific permitted development rights in a defined area. For HMOs, the most common use is removing the automatic right to change a family home (Use Class C3) into a small HMO (Use Class C4), meaning landlords in that area must apply for planning permission before converting.
Do I need planning permission to create an HMO?
It depends on the property and the location. Converting a home to a small HMO of up to six occupants is usually permitted development unless the area is covered by an Article 4 Direction, in which case you need planning permission. A large HMO of seven or more occupants is sui generis and always requires a planning application.
Is HMO planning the same as HMO licensing?
No — they are separate. Planning permission governs the lawful use of the building, while an HMO licence, issued by the council's housing team, governs standards and management once it is let. A property can need both, and satisfying one does not remove the need for the other.