Building regulations guidance for homeowners

The building regulations are a set of standards put in place by the Government to ensure that building work is carried out safely and correctly. If you build in accordance with the regulations, your home will be safe and comfortable for your family to live in.

Does my work need building regulations approval?

Most typical home improvement work requires building regulations approval, but the following are referred to as exempt work if they meet certain criteria:

  • conservatories;
  • porches;
  • detached garages;
  • carports;
  • sheds and summerhouses;
  • satellite dishes, aerials and antennae

Before these can be declared exempt from the building regulations, they have to meet the criteria outlined on this page.


A definition of a conservatory is a single-storey extension which has translucent or transparent material on at least three-quarters of the roof and half of the external walls. To be exempt, your conservatory must satisfy the following criteria:

  • It must be at ground level only
  • The internal floor area must not exceed 30m2
  • It must not be used for any other purpose (eg. kitchen, or living/ sleeping accommodation)
  • You keep the existing external doors and/or windows
  • The doors and windows (ie the glazing) must comply with Part K of the building regulations and safety glass must be used in critical locations.
  • If you are heating the conservatory it must be independently controlled (ie. completely separate to the system used for your house)
  • You must not make a new opening or increase the size of the existing one.
  • Any fixed electrical installation must meet the requirements of Part P (Electrical Safety).

A porch

If your porch includes a cloakroom with a w/c you will need to make a building regulations application. Visit to download an application form.

To be exempt, your porch must meet the following criteria:

  • It must be built at ground level only
  • The floor area must not exceed 30m2
  • The windows and doors (ie. the glazing) must comply with Part K of the building regulations
  • Any fixed electrical installation must meet the requirements of Part P (Electrical Safety) *
  • You must keep the existing entrance door between the house and the porch
  • If the property has ramped or level access for disabled people, the porch must not adversely affect access.

Attached garages

Garages which are structurally connected to an existing house are classified as attached regardless of whether there is a doorway connecting them. Before building an attached garage you will need to submit an application to Building Control. Please refer to the Extending, Converting or Improving your Home guide for guidance on how to make an application and the fee payable.

An attached garage is treated in a similar fashion to an extension but:

  • not all the Regulations apply, depending on the intended use of the building.
  • in the interest of fire safety, if there is a door between a garage and the dwelling it should have 30 minutes fire resistance and be self closing. This opening must incorporate a step of at least 100mm between garage and dwelling floor.
  • the positioning of an attached garage must not affect the fire safety precautions of the existing house, e.g. must not jeopardise an escape window either on the ground floor or the first floor. If in doubt please contact us.

Detached garages

A garage is detached if it is ‘structurally unconnected to a dwelling’ and ‘used for the storage of cars’. To be exempt it must meet the following criteria:

  • it must be less than 15m2
  • it must be single storey
  • it must not contain any sleeping accommodation

If your garage is more than 15m2 but less than 30m2, you do not need to make a building regulations application providing it doesn’t contain sleeping accommodation and is either:

  • more than 1m from any boundary at any point, or
  • constructed substantially of non-combustible material

If the garage has a floor area exceeding 30m2 you will need to make a building regulations application and be aware of the following in order to comply with regulations:

  • Garages do not have to resist moisture penetration. Consequently, Building Control will not enforce the use of damp proof courses, membranes or other proprietary items for resisting rain penetration.
  • Like any other extension, a garage is required to have a proper drainage system for rainwater drainage.
  • Any part of a detached garage that is less than 1m from the boundary should be non-combustible.


You do not need to make a building regulations application if your carport:

  • is built at ground level
  • has an internal floor area which is less than 30m2
  • is open on at least two sides

Sheds and summerhouses

If you want to erect a small detached building in your garden - eg. a shed or summerhouse - you do not need to make a building regulations application if:

  • the floor area is less than 15m2 and the building does not include sleeping accommodation
  • the floor area is between 15m2 and 30m2 , does not include sleeping accommodation and is either at least 1m from any boundary or constructed of substantially non combustible materials.

Satellite dishes, aerials and antennae

The building regulations do not generally apply to satellite dishes, aerial and antennae but you should ensure that the installation is safe and the fixing point stable.

Roofing and reroofing work

Some roofing projects require building regulations approval.

Visit our Guidance for re-roofing projects page for advice and information.

Planning permission

We recommend that you contact Development Management to establish whether your work needs planning permission. If you live in Horsham email, if you live in Crawley email

Contact Building Control

If you have any questions about a home improvement project, please email us at