HMOs & Conversions
An HMO (house in multiple occupation) is a property rented by several unrelated tenants who share facilities. AVA Home Design designs HMO conversions and layouts across London and the Home Counties to maximise lettable rooms and rental yield while meeting room-size, amenity and planning rules, and advises on Use Class C4 versus Sui Generis and Article 4 directions.
HMOs are one of the most profitable things a landlord can do with a property, and one of the easiest to get wrong. The difference between a scheme that lets well and one a council refuses usually comes down to room sizes, amenity provision, and getting the planning class right before any drawings are done.
We design HMO layouts that hit the minimum standards your council licenses against, plan extensions or loft conversions where they add lettable rooms, and confirm the planning route (permitted development, a full application, or Sui Generis) at the very start.
Types
- Small HMO (Use Class C4)
- Shared by three to six unrelated occupants. May be permitted development from a family house unless an Article 4 direction applies.
- Large HMO (Sui Generis)
- Seven or more occupants. Always needs full planning permission, and usually more amenity and fire provision.
- Flat conversion
- Splitting one house into several self-contained flats, addressing minimum space standards, parking and amenity space.
- HMO plus extension or loft
- Adding floor area at the same time as the conversion to increase the number of lettable rooms.
Frequently asked questions
- What's the difference between a C4 and a Sui Generis HMO?
- Use Class C4 covers a small HMO shared by three to six unrelated occupants. A large HMO of seven or more occupants is Sui Generis and always needs planning permission. The class affects whether you can convert under permitted development and what the council requires, so we confirm which applies before any design work.
- What is an Article 4 direction and does it affect my HMO?
- Many councils have made Article 4 directions that remove the permitted-development right to convert a family house into a small HMO, meaning a full planning application is needed even for a small C4. Whether your address is covered changes the route entirely, so we check it at the outset.
- How do you maximise the number of rooms?
- We design layouts that meet minimum room sizes and amenity standards while using the floor area efficiently, and where it adds rooms we plan a rear extension or loft conversion at the same time. The aim is the best compliant yield, not the most rooms on paper that a council would refuse.
- Do HMO rooms have to be a minimum size?
- Yes. National and council standards set minimum floor areas (commonly 6.51 square metres for a single room used by one person, and more for double rooms), plus kitchen and bathroom provision per occupant. We design to the standard your council licenses against so the scheme is both lettable and lawful.