Check if your work needs a building warrant

When you need a building warrant

Before you start building or changing something in your home or business, you may need a building warrant.

A building warrant is permission to start building work. It makes sure your work is safe and follows the rules. It is illegal to start work without a building warrant if one is required.

Work that usually needs a warrant

You will likely need a building warrant if you are:

  • putting up a new building
  • changing the structure or use of an existing building
  • converting a space, like a loft or garage
  • extending or demolishing a building

Permission is granted in the form of a building warrant. You must obtain this before starting work.

Work that may not need a warrant

Some small changes do not need a warrant, such as:

  • replacing a kitchen or bathroom (if the layout stays the same)
  • decorating inside your home
  • putting up a small shed or greenhouse (within size limits)
  • replacing windows or doors (if they are the same size and type)

Even if a warrant is not needed, the work must still meet building standards.

Conversions that may need a warrant

You need a warrant if you are changing how a space is used. This includes:

  • turning a loft into a bedroom
  • converting a garage into a living area
  • changing a shop into a flat

Page last modified: 31 December 2025