Key Takeaway
Many extensions, loft conversions and garage conversions can be built under permitted development, with no planning application.
Many extensions, loft conversions and garage conversions can be built under permitted development, with no planning application. But "I don't need planning" and "I can prove I didn't need planning" are two different things. A Lawful Development Certificate closes that gap.
What is a Lawful Development Certificate?
A Lawful Development Certificate (LDC), also called a Certificate of Lawfulness, is a formal decision from your council. It confirms that a proposed project is lawful and does not need planning permission. A separate type of certificate covers development that already exists.
Is it compulsory?
No. If your project genuinely falls within permitted development, you can build without one. Most homeowners apply anyway:
- Selling your home: buyers' solicitors often ask for proof that work was lawful.
- Mortgages: lenders may want evidence.
- Neighbour disputes: a certificate settles the question if someone complains to the council.
- Peace of mind: you know before you start that the council agrees.
When permitted development may not apply
Permitted development rights do not apply to flats and maisonettes. They can be restricted for listed buildings, in conservation areas, under Article 4 directions, or by earlier planning conditions. There are also limits on size, height, materials and position; go slightly beyond them and planning permission is needed. See permitted development vs planning permission.
What you need to apply
- existing and proposed floor plans and elevations, accurately drawn to scale
- a site location plan
- a description of the work and how it meets permitted development limits
- the council fee
Unclear or inaccurate drawings can lead to refusal or requests for more information, which adds delay.
Cost and timescale
In England, the council fee for a proposed-development certificate is half the fee for the equivalent planning application. Councils typically aim to decide within about eight weeks.
Certificate vs planning permission
A certificate is a legal test of whether the project fits the rules. The council does not weigh design or neighbour opinion the way it does on a planning application. If a certificate is refused, you can amend the design, apply for householder planning permission, or appeal.
Don't forget Building Regulations
A certificate covers planning only. The work will still need Building Regulations approval. See our guide to building regulations drawing packages.
How Hampshire Build can help
Hampshire Build is a fixed-fee residential architectural design practice with more than 20 years' experience and a 95% planning approval rate. We prepare the drawings for Lawful Development Certificate applications for extensions, loft conversions and garage conversions. Your measured survey is booked within 10 working days of your deposit. Your first drawings follow within 15 working days of the survey.
Not sure which route you need? Run our free Project Feasibility Check or book a free 30-minute consultation. Before you apply, it is also worth reading our guide to an extension feasibility study.
FAQs
Do I legally need a Lawful Development Certificate?
No, but it is strongly recommended as proof the work was lawful, especially when you sell.
Can I start building before the certificate is issued?
You can, but you risk the council disagreeing. Most homeowners wait.
Is a loft conversion permitted development?
Many are, within limits on volume, materials and position. A certificate confirms your design qualifies.
What if my certificate is refused?
Revise the design, apply for householder planning permission, or appeal.