Typical timeframes

In most cases planning permission is valid for three years. This means you have three years in which to start building work on site. Be aware it can take longer to get to the building stage than you might have anticipated.  For instance, if you need to have an ecology survey, there may be a specific season when that can be done. 

If you are buying a site that comes with consent for a house to be built on it, check when permission is due to expire before signing on the dotted line. Make sure there is sufficient time to get diggers on site before it runs out. The date is shown on the decision notice issued when consent was granted.

Other types of projects have slightly different timelines. For instance, conversion of an agricultural building to residential use made through a prior approval process, known as a Class Q permitted development, requires building work to be completed (not begun) within three years. Whether you’re building a home extension or converting a barn, it’s important to have a clear idea of the time scales.

Planning conditions

Planning conditions are attached to every permission for development granted by the local planning authority. These will be shown on your decision notice. Basically, they are the fine print. And they need to be checked as soon as you receive your approval.

Some conditions will need to be dealt with before building work begins.  For instance, there may be  conditions which require information to be submitted and agreed by the planning authority. Some conditions are relatively simple, such as suppling examples of building materials but others are more complex, like investigating ground conditions. Complying with these conditions can take weeks which you need to factor into your build schedule.

Failure to discharge pre-commencement conditions before building work starts could result in your project becoming unlawful or enforcement action being taken. Councils have eight weeks to discharge planning conditions but don’t expect your project to be fast-tracked through the system. Many planning departments are under-resourced and even the simplest of schemes can be delayed. So, give yourself plenty of time to comply with the conditions.

Full or outline planning permission?

It’s essential to know which type of permission you have. As the name suggests, full planning permission gives consent to an entire building project. It requires complete details of a scheme, such as orientation of the building, scale, site elevation, parking and drainage. If granted, it means all the details of the application are approved and the scheme has got the green light after satisfying any conditions attached to the consent.

Outline permission is typically used for bigger developments. The local authority is essentially agreeing in principle to the scheme – with the specifics, called “reserved matters” put aside to be decided later.

In both cases, you have three years to take action to keep your planning permission from expiring. So, what do you need to do?

How to keep permission alive

In the past, you could apply to extend the time limit of a permission, but this is no longer allowed.  The aim is to make sure that if developers have consent to build homes, they use it. Many councils, especially in the south of England, are concerned about “land banking” – or sitting on a developable site until it reached peak value rather than building on it. If you have outline permission, you will need to submit the specific details for approval before the three years run out. After approval of all the reserved matters are agreed, you then have another two years in which to begin work on site.

If you have full planning permission, you need to make a start on building work on site within three years. But what if you aren’t ready to start? What constitutes building work? This has been the subject of court cases.

In legal terms, the actions or “material operations” that demonstrate the beginning of work are defined in the Town and Country Planning Act 1990. They include any construction, demolition, digging foundations or the laying of any underground main or pipe. This means the work can be quite minor, such as digging a trench for a foundation. Of course, the trench needs to be where the foundations are in the drawings that received planning consent. It can’t just be anywhere on the site.

If in doubt, get professional advice or check with your local authority that your starter work meets the legal requirements.

Reapplying for planning permission

It is simplest to try and stop the permission from expiring by starting building work. But if you miss the deadline, the alternative is to reapply for planning permission. Under a legislation update made in October 2023, councils now have more power to refuse planning applications from those who let their permission lapse by not starting work within the three-year timescale.

That said, an application for a home extension or conversion should be considered favourably, unless there are any changes since the original consent was granted or circumstances have altered. Before reapplying for planning permission, check if there are any differences in local planning policy or changes to the site’s context or surrounding area, including ecology that could affect your project. If there are changes, then you might need to hire an architect to amend your proposals to the current conditions.

There’s no guarantee you will be successful second time round but having been granted permission previously sets a useful precedent.  Hopefully, you will still have the drawings, surveys and additional information required. However, you will still need to pay the planning application fee again. Some reports might also need updating, for instance ecology. If any surveys identify a change in circumstances, this might make it tricky to win approval again.

While planning procedures are set out by national legislation and guidelines, local authorities can vary in how they interpret them. So, if you think your permission is about to expire, or has expired, it’s best to talk about the specifics of your case to a local architect or planning consultant and get professional advice.

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