What is Sui Generis Planning in HMOs? What You Need to Know

Sui Generis Meaning in HMO Planning

Sui Generis is a type of planning application used for properties that do not fall into any specific category. The latin term “sui generis” means “in a class of its own”.

There are several buildings that fit into the Sui Generis planning category, including buildings such as theatres, nightclubs and casinos. It is also used to class HMOs that fit certain criteria.

As far as HMO planning classes are concerned, there are generally 3 to be aware of.

  • C3 (Residential): Used to categorise properties or houses that are primarily used as single-family houses or as residence for a single household.
  • C4 (HMO): The use class used when you have three or more unrelated tenants living together who share facilities such as the kitchen and living areas. This use class refers specifically to smaller HMOs that have 6 occupants or less.
  • Sui Generis (HMO): Similar to the C4 use class, this is used for HMOs with three or more unrelated tenants living together and sharing facilities. However, this use class is used for HMOs with 7 or more occupants. Therefore, constituting a large HMO.

To summarise, this means that up to 6 occupants, an HMO will fit into the C4 use class. Anything higher than this, and Sui Generis planning is required.

How Does C4 Planning Differ From Sui Generis Planning?

The planning process for Sui Generis properties tends to be more complex and involves some additional considerations compared to C3 to C4 or C4 to Sui Generis.

The first consideration is that often C3 to C4 can fall under what is known as permitted development. This planning right allows you to change the use class of the property without requiring a full application to your local planning authority. However, you may still need to take into account other considerations, such as Article 4 directions.

Sui Generis, however, will always require a full planning application, regardless of whether you are changing the property from C3, C4 or even from another Sui Generis building (e.g. if you are converting a nightclub into an HMO).

Because a Sui Generis property is considered to be the closest to commercial use, the requirements are stricter and consider the wider implications of the HMO on the local area.

For more information on converting C3 to C4 or Sui Generis and their differences, read our article “Converting a C3 House to HMO C4 & Sui Generis”.

Why Do Councils Require Sui Generis Planning Applications?

Local planning authorities are concerned about how proposed HMOs could potentially impact the local policies in force in your area. As you might assume, councils want to prevent a huge influx of large HMOs in their district, which if not controlled could put a big strain on local services as well as cause overcrowding or an increase in anti-social beheviour.

Large HMOs occupy a greater number of tenants and, therefore, councils require the opportunity to first assess the wider impact of proposed HMOs on the local area before they are granted permission.

Some core elements that local councils will consider include:

  • Parking & Highway Impact: Councils are concerned with the impact a large HMO could have on parking availability and congestion. They will consider their minimum parking standards as well as access to local public transport.
  • Character & Appearance Impact: You local planning authority are conscious of the “look and feel” of properties in the area. One of their considerations will be how your proposed development fits in with the existing surroundings.
  • Residential Impact: Councils are concerned with how a development may impact the surrounding area in terms of noise or anti-social behaviour. This is a particularly high consideration in mostly family-occupied areas.
  • Living Standards: Your council will want to ensure that the HMO offers high quality living standards to the occupants.

What Does a Sui Generis Planning Application Entail?

If you are looking to invest in a large HMO over over 6 occupants, you will need to know what is required from a Sui Generis planning application (as well as how to make yours a successful one).

Design & Access Statement

The first core component of your Sui Generis planning applications is your Design & Access Statement. This is essentially a small report that needs to accompany your application and it details the process involved in the development proposal and explains the your designs.

The DAS essentially will explain the design concepts and principles that have been applied to your HMO development. The main reason for requiring this is so that your local planning authority understands that you have considered your HMO’s immediate and wider impact in terms of physical, social and economic factors.

Your DAS will include elements such as:

  • The scale of the development
  • The property layout
  • Any proposed landscaping
  • Appearance and visual aspects
  • Dimensions of the building(s) in relation to the surroundings

A well prepared DAS is a crucial part of ensuring your planning officer sees you have fully considered your resposbilities to access and local policies, and that this is reflected in your proposal.

c3 to c4 or sui generis house


Another core part of your Sui Generis planning application is detailed drawings. You will require drawings for both Existing and Concept.


Your existing drawings should illustrate how your chosen property currently looks before any development work has taken place. These drawings should include plans, sections and elevations and need to contain the correct level of detail required for the application.

Generally, most property owners should already have existing drawings of the property. However, if you do not, this is something that you will need to obtain, which you can do through a measured survey.

If you are working with an HMO architect or project manager, they can generally help you take care of these drawings and will understand the exact format that local councils will require.


The concept drawings you provide in your application will demonstrate the proposed changes to the property following the development and how you plan for the space to look afterwards.

There are several factors that will play a part in your proposed development and concept drawings, including:

  • Room Sizes: Including the sizes of the proposed bathrooms, bedrooms, kitchen and living spaces.
  • HMO Licencing: All large HMOs require a mandatory HMO licence, and the drawings should illustrate that your proposal is compliant with those requirements.
  • Fire Safety Measures: Clearly illustrating the fire safety measures that have been considered and that they are compliant with building regulations.
  • Retained vs New Building Work: Clearly illustrated on the drawing

An OS Map (Ordinance Survey Map) is also required as part of your Sui Generis application to show the location of the property in the neighbourhood.

Existing and Concept drawings do require skill, experience and precision to ensure the correctly convey everything that is required for a planning officer to consider the application. When working with HMO architects or professionals, they will be able to help you with pulling together fully compliant, high quality drawings to ensure a smooth application process.

Flood Risk Assessment

If your proposed HMO falls into what is considered a “high-risk zone”, you will need a flood risk assessment as part of your Sui Generis application. You can use the Government UK Flood Risk Service to work out the flood risk score for your specific area.

If you require a flood risk assessment, this can be conducted by an assessor.

Transport Statement

Though not a requirement, a common pitfall of many Sui Generis applications is related to the access to transport and parking availability.

A solid and through out transport statement can add strength to your application process, particularly if there is some concern over parking availability. Your statement can demonstrate the access in the area to other means of transport, such as local bus routes to core districts and close proximity bike and scooter rentals.

If you are planning to include bicycle storage as part of your DAS, this can be a great way of demonstrating a consideration of transport in your application. If you include a Transport Statement, this can be carried out by a transport consultant.

Management Plan

Some councils may request an HMO Management Plan as part of your Sui Generis application.

The plan requires you to illustrate how you plan to manage your HMO in terms of maintenance and cleanliness. It can require elements such as waste management plans, tenancy agreements and parking arrangements.

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