Article 4 directions on C3 to C4: checking before you buy
Without a direction, converting a house to a small HMO needs no application. With one, it needs permission that a concentration policy may refuse. How to check, and what to do with the answer.
An article 4 direction HMO check belongs in the due diligence on every house you buy to let to sharers, and it takes about twenty minutes. Without a direction, Class L of Part 3 of the General Permitted Development Order 2015 lets you change a dwellinghouse in Class C3 into a small HMO in Class C4 with no application at all. With one, the same change needs planning permission, and in a street where the council's concentration policy is already breached that permission is unlikely.
The gap between those two positions is the difference between a viable purchase and a house you cannot use as intended.
What the direction does to the C3 to C4 right
Article 4 of the Order lets a local planning authority withdraw a permitted development right in a defined area. The direction does not ban the change of use. It removes the automatic permission, so the change becomes development requiring an application, judged against the development plan.
Directions are made under a procedure set out in the Order, with publicity and a period for representations. Where the authority gives at least twelve months notice before the direction takes effect, it avoids the compensation liability that section 108 of the Town and Country Planning Act 1990 would otherwise create. That is why most HMO directions are announced a year ahead, and why the announcement date and the effective date are different.
National policy expects directions to be limited to situations where they are necessary to protect local amenity or the wellbeing of the area, and to be applied to the smallest geographical area possible. Some authorities apply them borough-wide anyway, and those have been challenged with mixed results.
Finding the direction and its boundary
Start with the council's planning policy pages, which usually carry a dedicated article 4 section listing every direction with its date and its map. Then cross-check against the national article 4 direction dataset on planning.data.gov.uk, which holds the geographic boundaries in a machine readable form.
A local land charges search will reveal a direction affecting the property, so it appears in conveyancing. The problem is timing: by the time the search comes back you may have spent money on surveys and legal fees. Check first, search later.
Boundaries are the part that catches buyers. A direction can follow a ward boundary, a set of named streets, a polygon drawn around a university, or one side of a road. Two houses facing each other across the same street can sit on opposite sides of the line. Download the map at full resolution and find the property on it rather than trusting a text description.
Reading the wording carefully
Once you have the direction, read the operative words rather than the council's summary of them.
Points to check:
- Which right is withdrawn. Most HMO directions withdraw only the C3 to C4 change. Some also withdraw householder rights or the office to residential change, which affects other plans for the building.
- Whether the withdrawal is one-way. The change from C4 back to C3 is normally left in place.
- The date the direction came into force, because a use established before that date may be lawful and unaffected.
- Any exclusions, such as properties already in lawful HMO use or buildings above a stated size.
- Whether the direction has been confirmed, since a direction can be made, consulted on and then modified before confirmation.
Where the wording is ambiguous, email the council's planning policy team and keep the reply. A written answer from the authority is worth more in a later dispute than a note of a phone call.
Concentration policies inside a direction area
A direction only changes the procedure. What decides the application is policy, and in university towns and cities with large private rented sectors that usually means an HMO concentration policy.
These policies are typically expressed as a proportion of properties within a stated radius of the application property that are already in HMO or other non-family use, with a threshold above which further HMOs are refused. The percentage and the radius are both set locally, in the local plan or in a supplementary planning document, and they vary widely. Some authorities add a sandwiching rule preventing an HMO between two family dwellings, or a rule about the proportion of a single street frontage.
Get the policy text and the council's own HMO data before you offer on a property. Many authorities publish the licensing register, and some publish a mapped HMO layer showing which addresses already count. Where the council does not publish it, ask for the data under a freedom of information request, and factor the response time into your timetable.
The calculation is usually done from the council's records rather than from your own survey of the street, so a property that looks surrounded by families may still fail if student lets are recorded nearby.
Evidence for an application in a direction area
If the property is inside a direction and you decide to apply, the pack should answer the concentration policy first and the amenity questions second.
A Planning Statement should set out the concentration calculation as you understand it, with the source of the data and the date. If the calculation falls below the threshold, say so and show the working. If it falls above, the application needs another argument, such as an existing lawful HMO use, a property that is unsuitable for family occupation, or a material consideration specific to the site.
Then the practical evidence: floor plans with room areas and communal space, a bin and cycle store shown on the layout, and a parking position supported by a Parking Survey to the Lambeth methodology where the council's standard is not met on site. Surveys taken in university vacations prove nothing about term-time parking stress, so time them properly.
Our guide to the evidence pack for a change of use application covers the general structure, and the same discipline applies here.
What to check at acquisition
A workable sequence before exchange:
- Confirm whether an article 4 direction covers the property, using the council's map and the national dataset.
- Read the direction and note its effective date.
- Check the planning history for the address, including any conditions restricting occupation.
- Check the licensing register for an existing HMO licence and its occupancy.
- Get the concentration policy text and the council's HMO data for the radius it specifies.
- Where the seller claims an existing lawful HMO use, require evidence, and consider making the purchase conditional on a lawful development certificate under section 191 of the 1990 Act.
- Price the risk. A house that needs permission it will not get is worth the family house value, not the HMO value.
Sellers and agents describe properties as HMOs when they mean the house has six bedrooms. The two are not the same, and the difference is worth tens of thousands.
Where the enforcement risk sits
Using a property as a C4 HMO inside a direction area without permission is a breach of planning control. The council can serve an enforcement notice requiring the use to stop, and non-compliance with a notice is an offence.
Immunity through the passage of time is available, and the Levelling-up and Regeneration Act 2023 moved the enforcement time limit in England to ten years for all breaches. Which limit applies depends on when the breach began, so check the commencement position for your facts. Ten years of continuous unlawful HMO use is a long time to hold a property with an unresolved planning position and no clean title.
A lawful use can also be lost. Where a property reverted to family occupation for a period, the earlier HMO use may have been abandoned, and our note on how a lawful use can be lost sets out how that argument runs.
Enter your postcode on PlanScope to see the designations affecting an address and which reports a change of use application would need.
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
Where do I find out if an article 4 direction applies?
Start with the council's planning policy pages, which list directions with dates and maps, then cross-check the national article 4 direction dataset on planning.data.gov.uk. A local land charges search will also reveal one, but it arrives late in a purchase, so check the published sources before you spend money on surveys.
Does an article 4 direction ban HMO conversion?
No. It removes the automatic permission given by Class L of Part 3 of the General Permitted Development Order 2015, so the change becomes development requiring a planning application. Whether permission is granted depends on the council's concentration policy, amenity standards and parking position for that specific address.
Why do councils announce directions a year in advance?
Because section 108 of the Town and Country Planning Act 1990 can create a compensation liability where a permitted development right is withdrawn. Giving at least twelve months notice before the direction takes effect avoids that liability. It also means the announcement date and the effective date are different, and the effective date is the one that matters.
What is an HMO concentration policy?
A local policy setting a threshold for the proportion of properties within a stated radius that are already in HMO or other non-family use, above which further HMOs are refused. Both the percentage and the radius are set locally. Some councils add a sandwiching rule preventing an HMO between two family dwellings.
How do I prove an existing lawful HMO use?
Apply for a lawful development certificate for an existing use under section 191 of the Town and Country Planning Act 1990, supported by tenancy agreements, council tax records, licensing history and statutory declarations. Where a seller claims a lawful HMO use, consider making the purchase conditional on that certificate rather than taking the claim on trust.
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.