HMO planning permission in London: three tests, two regimes
A London house share can need planning permission, a licence, both or neither, and the answer turns on how many people live there, whether they form one household, and whether your council has withdrawn the permitted development right. This guide takes the three tests in order, compares three boroughs' Article 4 directions with their dates, and explains why a licence never replaces planning consent.
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Do you need planning permission to run an HMO in London?
It depends on which of three tiers the house falls into. A single household in a house is Use Class C3. Three to six unrelated people sharing a kitchen or bathroom, as their only or main home, make a small HMO in Use Class C4. More than six residents make a large HMO, which is sui generis, meaning it belongs to no use class and needs planning permission whatever the council's policy.
Moving between C3 and C4 is a change of use, but Class L of Part 3 lets you make it without an application, in either direction. The right is withdrawn where a council has made an Article 4 direction, and in several London boroughs the direction covers the whole borough. Once that applies, a conversion needs a full planning application.
Two traps catch new landlords. First, the line sits at seven residents, so a six-person share that takes a seventh tenant moves from a small HMO to a large one. Second, Class L.1 does not permit a switch between C3 and C4 that results in two or more separate dwellinghouses from a building that was one. A house split into self-contained flats is a different application altogether.
Which use class and which regime applies to your house share?
Planning sorts a shared house by use class, and licensing sorts it by headcount and households. The two tests use different numbers, which is why a property can pass one and fail the other.
Arrangement
Planning use class
Planning route
Mandatory licence?
One family or household
C3 dwellinghouse
No change of use
No
3 to 6 unrelated people sharing amenities
C4 small HMO
Permitted development under Class L, unless an Article 4 direction removes it
Only at 5 or 6 people from 2 or more households
7 or more residents
Sui generis large HMO
Planning permission always required
Yes, at 5 or more people in 2 or more households
Self-contained flats in one building
C3 for each flat
Planning permission for the conversion
Depends on the building and the council scheme
Sources: Planning Portal, Use classes (C3, C4, sui generis); Town and Country Planning (General Permitted Development) (England) Order 2015, Schedule 2, Part 3, Class L; Licensing of Houses in Multiple Occupation (Prescribed Descriptions) (England) Order 2018, in force 1 October 2018.
What does an Article 4 direction do to a small HMO conversion?
An Article 4 direction takes away the permitted development right to switch from C3 to C4, so the switch needs an ordinary planning application and the council judges it against its local plan. Our guide to conservation areas and Article 4 directions explains how directions are made and how to check your street.
Under Schedule 3 of the 2015 Order, a non-immediate direction must give at least 21 days for representations and take effect between 28 days and 2 years after the notice date. The longer lead time matters to landlords, because a direction announced in July can still allow conversions to proceed lawfully for a short window afterwards.
A direction normally bites only on new conversions. Redbridge states that its direction does not affect C4 HMOs that existed before 6 December 2019. That is also why an existing HMO can be worth proving. A Lawful Development Certificate under section 191 settles that the use pre-dates the direction, and the evidence is a dated tenancy record, not a recollection.
How do three London boroughs treat small HMOs?
Haringey, Redbridge and Hounslow all removed the C3 to C4 right, but at different dates and over different areas, so a rule that holds in one borough tells you nothing about its neighbour.
Borough
Area covered
Dates
Other points the council states
Haringey
14 wards, including Tottenham Hale, Seven Sisters, Bounds Green and West Green
Direction in force 30 November 2013
An HMO with 7 or more occupants needs planning permission in all parts of the borough
Redbridge
Borough-wide, covering small HMOs in Class C4
Direction in force 6 December 2019
Any HMO of up to 6 people started after 6 December 2019 needs consent; an HMO of 7 or more people needs permission; C4 HMOs that existed before that date are unaffected
Hounslow
Whole borough, except open land, industrial areas, Chiswick Business Park, Bedfont Lakes Business Park and Mogden Sewage Works
Notice 6 July 2022, confirmed 8 August 2023, in force 4 September 2023
Planning permission needed to convert a dwelling to a small HMO from the start date
Sources: London Borough of Haringey, Article 4 Direction: Houses in Multiple Occupation; London Borough of Redbridge, Article 4 Direction on C4 HMOs; London Borough of Hounslow, Article 4 Directions. Council pages read 13 October 2026. Check the current direction map for your address before relying on this table.
A licence and planning consent are separate decisions
Planning decides whether the use is acceptable on that site. Licensing decides whether the property is safe and well managed for the people living there, and a licence does not authorise a use that needs planning permission. Mandatory licensing applies to a property occupied by 5 or more people in 2 or more separate households, a definition that has applied since 1 October 2018. Redbridge adds an additional licence for 3 or 4 people forming 2 or more households.
5+ people Mandatory licence
2 or more Households
1 Oct 2018 Rules in force
What do licence conditions mean for the floor plan?
The mandatory licence conditions set minimum room sizes in law, so the layout you draw for planning has to be a layout the licence will accept.
6.51 square metres: one adult
A bedroom for one person aged over 10 must be not less than 6.51 square metres under the 2018 conditions. A room below the minimum breaches the licence condition, whatever the planning drawing calls it.
10.22 square metres: two adults
A room for two people aged over 10 must be not less than 10.22 square metres. Loft and basement rooms need a floor measurement before they are labelled as double bedrooms.
4.64 square metres: one child under 10
A room for one person under 10 must be not less than 4.64 square metres. The age bands are why the licence conditions ask who will occupy each room.
Waste storage
The licence must require the holder to follow the council's scheme for storing and disposing of household waste before collection. A bin store shown on the plan answers both the licensing officer and a planning officer's amenity question.
Does an HMO conversion also need Building Regulations approval?
Often yes, even where planning is permitted development. Regulation 5 of the Building Regulations 2010 lists changes that count as a material change of use, including a building that contains a flat where previously it did not, and one that contains a room for residential purposes where previously it did not. Converting an office, shop or garage block to shared housing therefore triggers building control, covering fire separation, means of escape and ventilation.
A family house moving from C3 to C4 without new rooms may not trigger regulation 5, but the licence conditions will still ask for fire detection and safe escape. Fire safety sits in both regimes, so a plan drawn once for planning and licensing saves a redraw later.
How do you get HMO planning permission?
The sequence below keeps planning, licensing and building control from contradicting each other.
1
Count the residents and test the household
Decide the number of people the house is arranged for and whether they form one household. That fixes C3, C4 or sui generis before anything else.
2
Find out whether Article 4 applies to the address
Use the council's direction map, not a postcode guess. Haringey's covers 14 wards and Redbridge's covers the whole borough, so ward and date both matter.
3
Measure the property and test every room
A measured survey gives floor areas to compare with 6.51 and 10.22 square metres. Rooms that miss become lounges or kitchens in the proposal.
4
Draw existing and proposed plans
Show each bedroom, the shared kitchen and bathroom, bin and cycle storage and the escape route. The same set serves the planning application and the licence.
5
Apply, and prepare the licence alongside
Submit the planning application, then apply for the mandatory or additional licence where the headcount demands it. Run them together so the licence layout and the approved layout match.
6
Prove existing HMOs with a certificate
For a house already let as a small HMO from before a direction took effect, a section 191 Lawful Development Certificate records that the use is lawful.
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Frequently asked questions
Do I need planning permission to turn a house into an HMO?
For 3 to 6 unrelated people you usually do not, because Class L of Part 3 permits a change from C3 to C4 without an application. You do need permission where your council has made an Article 4 direction covering the address, and you always need it for 7 or more residents. A licence is a separate requirement, so check both before you buy or let.
What is the difference between a C4 HMO and a sui generis HMO?
A C4 HMO is a small shared house occupied by between 3 and 6 unrelated individuals who share basic amenities such as a kitchen or bathroom. A house with more than 6 residents is a large HMO, which is sui generis, a use that sits outside the use classes. Large HMOs need planning permission in every borough, with no permitted development route.
What is an Article 4 direction for HMOs?
It is a council order that removes the permitted development right to convert a dwelling to a small HMO in a defined area. The conversion then needs a planning application judged on local policy. Some London boroughs apply it across the whole borough, as Redbridge and Hounslow do, while Haringey applies it to 14 named wards.
When does an HMO need a licence?
Mandatory licensing applies to a property occupied by 5 or more people in 2 or more separate households, under the 2018 Order in force since 1 October 2018. Councils can add schemes. Redbridge, for example, runs an additional licence for 3 or 4 people forming 2 or more households. Check the council's licensing page for the address.
Does an HMO licence give me planning permission?
No. Licensing and planning are separate decisions made by different teams under different law. A licence confirms the property meets safety, amenity and management standards for its occupants. It does not authorise a use that needs planning permission, and the licence conditions apply to the layout whatever the planning drawings show.
What are the minimum bedroom sizes for an HMO licence?
Under the mandatory licence conditions in force since 1 October 2018, a room for one person over 10 must be at least 6.51 square metres, a room for two people over 10 must be at least 10.22 square metres, and a room for one person under 10 must be at least 4.64 square metres.
Can I convert to an HMO if my council has an Article 4 direction?
Yes, with planning permission, which the council grants or refuses on its merits. The council assesses an application against its local plan, so read the council's HMO policy for its room-size and amenity standards before you draw. Plans that show room sizes, bin storage and escape routes clearly give the case officer less to query.
What if my HMO has been running since before the Article 4 direction?
It can usually continue, because directions normally affect new conversions only. Redbridge states that its direction does not affect C4 HMOs that existed before 6 December 2019. A Lawful Development Certificate under section 191, supported by dated tenancy and utility records, proves the use pre-dates the direction and helps on a sale or a refinance.
Does turning a house into flats count as an HMO conversion?
No. Class L.1 does not permit a switch that results in two or more separate dwellinghouses from a single building, so splitting a house into self-contained flats needs planning permission. Whether the flats then need a licence depends on the building and on the council's scheme. Section 254 of the Housing Act 2004 has separate tests for flats.
Do HMO conversions need Building Regulations approval?
Frequently. Regulation 5 of the Building Regulations 2010 treats a building that gains a room for residential purposes, or a flat, where it had none before, as a material change of use. A family house changing from C3 to C4 without new rooms may not trigger it, but the licence will still require fire detection and escape routes.
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