Search site menuicon

Exempt detached buildings

Building regulations allow for the exemption of certain detached buildings, find out what is classed as exempt.

You don't need to make a building regulations application for some types of detached buildings.

Exempt buildings are:

  • a detached single-storey building (for example, garage, summerhouse) with no sleeping accommodation
    • with a floor area less than 15m2
    • with a floor area less than 30m2 and no point of the building less than 1m from the boundary, unless the building is mainly made of non-combustible materials
  • an extension to a building that consists of a conservatory, porch or covered yard/way with a floor area less than 30m2 and glazing that complies with the safety glazing requirements in Approved Document N.
  • a carport open on at least two sides
  • a temporary building not intended to stay up for more than 28 days
  • a greenhouse or agricultural building not used for retailing, packing, exhibiting or living in, and not less than one and a half times its height from any point of a building that contains sleeping accommodation

Even if you don't need Building Regulations permission, you might still need planning permission.

What are non-combustible materials?

Non-combustible materials include:

  • roof - tiled or slated pitched roof on timber trusses, or a flat roof with AA, AB or AC rated covering (for example, 12.5mm chippings, fire-rated fibreglass)
  • walls - brick and block masonry construction, or timber frame clad in non-combustible board
  • floors - concrete slab, or concrete beam and block

Will I need permission to carry out work on exempt buildings?

You'll need to submit a Building Regulations application if you:

  • carry out works to a controlled service or fitting, like drainage or heating
  • make a material alteration, like adding a first floor or a room to live in, or increasing the floor area

The following guide has been written to provide advice on common domestic works such as extensions, loft conversions, garage conversions, domestic cellar conversions and other alterations.

View the online guide to extending your home

Alternatively you can download a PDF copy of the guide -  pdf icon Extending Your Home 2014 [4Mb]

Any electrical works should be carried out by a Part P registered competent electrician who will self-certify their work. You can find a registered electrician in the Competent Persons Register.