Rights of Light and Residential Extensions: What Neighbours Need to Know

By Neil Goddard · 16 July 2026

Most people associate rights of light disputes with large commercial developments. Tower blocks, office schemes, that sort of thing. But some of the most common disputes actually happen between neighbours, usually when one of them builds an extension that blocks light to the other's windows.

If your neighbour has built, or is planning to build, a residential extension that cuts off natural light to your home, you may have a legal claim. Rights of light apply just as much to a two-storey rear extension as they do to a 30-storey skyscraper. The law does not distinguish based on the size of the development. What matters is whether your windows have enjoyed uninterrupted access to light for 20 years or more under the Prescription Act 1832, and whether the new building reduces that light below an acceptable level. You can read more about what a right of light is and how it comes into existence on our main guide.

The test for infringement is the same in a neighbour dispute as it is in a commercial case. A surveyor will assess whether the remaining light to your room falls below the so-called 50/50 rule, which asks whether at least half of the room still receives adequate natural daylight measured at table-top height. If the extension pushes the light below that threshold, you likely have an actionable claim.

One thing that catches people off guard is how planning permission fits into this. Your neighbour might have full planning approval or might be building under permitted development rights. Neither of those changes your position. Planning consent deals with public regulatory controls. Your right of light is a private property right, and it exists independently. A council granting permission for an extension does not override your legal rights as a property owner. These are two completely separate legal systems.

Timing matters a great deal in neighbour disputes. If you know about the extension before it is built, you are in a much stronger position. The courts can grant an injunction to prevent the building work from going ahead, or to require changes to the design so that it does not infringe your light. Once the extension is already up, your leverage shifts. You can still claim, but the court is more likely to award financial compensation rather than order your neighbour to tear down what they have built. That said, mandatory injunctions requiring demolition are not unheard of, particularly where the person building knew about the infringement and pressed on regardless. The decision in Regan v Paul Properties (2006) confirmed that courts should not simply assume damages are an adequate remedy. Each case turns on its own facts.

The practical reality is that most neighbour disputes settle without going anywhere near a courtroom. Nobody wants a drawn-out legal fight with the person living next door. Typically, the claim is raised, a rights of light surveyor carries out an assessment, and the parties negotiate a financial settlement. Understanding how compensation is calculated helps you know what a fair outcome looks like. Compensation in these cases is usually based on the diminution in value of the affected property, though in some circumstances it can be calculated as a share of the profit the neighbour gains from their extension.

If you think your neighbour's extension is affecting your light, the first step is to get a proper assessment done. Do not rely on gut feeling. What looks like a significant loss of light to you may or may not meet the legal threshold, and equally, what seems minor could actually amount to an infringement. A qualified rights of light surveyor can measure the impact precisely and give you a clear picture of where you stand.

It is also worth speaking to a solicitor early. Sending a well-drafted letter before construction starts can sometimes resolve the issue without any formal legal proceedings. If your neighbour knows you are aware of your rights and prepared to enforce them, they are far more likely to engage constructively, whether that means redesigning the extension or agreeing a compensation figure.

Neighbour disputes can feel personal in a way that commercial claims do not. But the legal principles are exactly the same. If you are unsure about your position, you can request a free assessment to find out whether you have a claim and what your options are.

Reference: Prescription Act 1832; Regan v Paul Properties Ltd [2006] EWCA Civ 1391