Count people and understand how they live
The use class depends on the actual arrangement, not just the number of bedrooms or the landlord's preferred description. Class C3 includes ordinary dwellinghouses occupied by a family and certain other household arrangements. A large family is not automatically an HMO because more than six people live together. [1]
Class C4 concerns small HMOs, including shared houses or flats occupied by three to six unrelated people who share facilities such as a kitchen or bathroom. A proposal for more than six HMO occupants falls outside C4; “sui generis” means it does not sit within a specified use class. [1]
Do not confuse a self-contained flat conversion with a shared HMO. The layout, access, amenities and pattern of occupation need to be described accurately before either the planning or licensing test can be applied. [1] [2]
Can a normal home become a small HMO without an application?
There is a national permitted-development route between C3 and C4, but local Article 4 directions can remove the C3-to-C4 right. Waltham Forest, for example, explains that its direction applies borough-wide and covers a house or flat becoming a small HMO. [3]
Check the operative direction and the property's planning conditions before relying on that route. A removed right means an application is needed for the relevant change; it does not itself decide whether permission will be granted. [4] [3]
What about a larger HMO?
Do not rely on the C3-to-C4 permission for a seven-person HMO. A larger operation needs its own planning assessment, including whether a proposed change from an existing use is material and whether a planning application is required. The label “sui generis” is not a permission. [1]
For an existing HMO, assemble the decision notices and evidence of the lawful occupancy and use before increasing numbers. Ask the planning team to assess the precise proposal rather than assuming that an existing HMO label authorises unlimited intensification.
Licensing uses a different test
National mandatory licensing generally concerns qualifying HMOs occupied by at least five people forming two or more households. Since 1 October 2018, the old three-storey condition no longer limits that scheme. Additional licensing can bring smaller HMOs within local licensing requirements. [2]
For example, a five-person shared HMO may remain within planning Class C4 while requiring a mandatory HMO licence. Conversely, a three-person HMO may need planning permission because of Article 4 and a licence under a local additional scheme. These are separate questions, not alternative descriptions of one approval. [2] [3] [5]
Record the intended operation
Prepare a consistent schedule of bedrooms, maximum residents, households, shared facilities and management arrangements. Use it across the planning drawings and licensing discussions so each team is assessing the same occupation, rather than different versions of the proposal. [2]