Many single-storey rear extensions can be built under permitted development, which means you do not need a full planning application. But permitted development is a set of rules, not a certificate. A Lawful Development Certificate, often shortened to LDC, is how you get a formal decision that your proposal is within those rules.
What it is
A certificate of lawfulness of proposed use or development is provided for under section 192 of the Town and Country Planning Act 1990. You submit drawings and details to the local planning authority, and they decide whether the proposal is lawful. If they agree, you receive a certificate.
Why people apply for one
- Certainty. You know your interpretation of the rules has been checked before you spend money on the build.
- Selling later. A buyer's solicitor may ask how you know the extension did not need planning permission, and the certificate answers that.
- Borderline cases. If the design is close to a limit, such as height or distance from a boundary, a decision in writing is worth having.
- Neighbours. If someone questions the work, you have documentation to point to.
What it does not cover
A certificate says nothing about building regulations, which still apply, or about the Party Wall etc. Act, which is separate. Some homes have had permitted development rights removed by a condition or by an Article 4 direction, and a certificate application is a good way to find that out. Our guides to building regulations approval and the Party Wall Act cover those parts.
Fees and timing
The application fee for a proposed development is set nationally and is a proportion of the fee for a full planning application. Decisions are generally made within weeks. The Planning Portal has the current fees and application process. We can prepare the drawings or work with your architect, so ask us if you want help.
Sources and further reading
Related services
See how we approach this
About the author
Written by JLS Building & Property Development Ltd, a family-run building contractor covering Bedfordshire, Cambridgeshire, Hertfordshire and Buckinghamshire. FMB member and SafeContractor approved. More about us. This guide is general information, not professional or legal advice for your specific project.