Exempt detached buildings

What is classed as exempt?

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?

These 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

Controlled alteration work

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
  • create an opening in a load bearing wall

Electrical works

Any notifiable 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.