Do I need planning permission to convert a house into an HMO?

Converting a family house (use class C3) to a small HMO of up to six unrelated occupants (use class C4) is permitted development in much of England - no planning application needed. But many councils have made Article 4 directions removing that right in some or all of their area, in which case planning permission is required. Larger HMOs of seven or more occupants always need planning permission.

What is an Article 4 direction for HMOs?

An Article 4 direction is a local order removing specific permitted development rights in a defined area. Councils commonly use them to require planning permission for C3-to-C4 HMO conversions in areas with high HMO concentrations. They apply street by street, so two properties a road apart can have different answers.

Is HMO licensing the same as planning permission?

No. HMO licensing (mandatory for most HMOs of five or more occupants, plus additional or selective schemes in some areas) is a housing-standards regime, entirely separate from planning. A licence does not grant planning permission, and planning permission does not remove the need for a licence.

HMO Planning Permission & Article 4 Directions

General guidance for landlords and developers in England. Last reviewed: 12 September 2026

General information, not a decision on any specific property. Confirm your position with your local planning authority before committing to a purchase or conversion. See our AI Disclaimer.

Small HMOs: often permitted development — until they're not

Converting a family dwelling (planning use class C3) into a small HMO of up to six unrelated occupants sharing facilities (use class C4) is permitted development in much of England — the change of use can happen without a planning application. This is exactly the kind of rule that looks simple until local orders get involved.

Article 4 directions change the answer street by street

Councils concerned about concentrations of HMOs can make an Article 4 direction removing the C3-to-C4 permitted development right in a defined area — sometimes a few streets, sometimes the entire borough. Where a direction applies, the same conversion needs a full planning application, typically judged against policies on HMO concentration, amenity and parking.

Article 4 directions are the single most common trap in HMO acquisitions: they are local orders, they don't show up in national legislation, and two properties a road apart can have different answers. Checking the actual designation at the actual property — not the borough's general reputation — is essential before exchange.

Larger HMOs always need permission

An HMO of seven or more occupants falls outside class C4 entirely (it is sui generis — in a class of its own) and always requires planning permission, Article 4 direction or not.

Licensing is a separate system

HMO licensing — mandatory licensing for most HMOs with five or more occupants, plus additional and selective licensing schemes some councils operate — is a housing-standards regime under housing law, not planning law. A licence does not grant planning permission, and planning permission does not remove the need for a licence. A viable HMO needs both positions resolved.

Building Regulations and beyond

Conversion works — new bathrooms, kitchens, fire separation between lettings, means of escape — engage the Building Regulations regardless of the planning position. Fire safety requirements for HMOs are more demanding than for a single dwelling.

Check a property's HMO position before you commit

ArchLens checks live official data for Article 4 directions at the property's actual location, assesses the change-of-use route, and sets out your council's policy position where a policy library exists — with every finding cited to its source.

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