How Rights of Light Compensation Is Valued and Calculated

By Neil Goddard · 4 June 2026

If a developer's new building blocks light to your property, you may be entitled to compensation. But how do surveyors and lawyers actually put a number on it? The valuation process is more structured than most people realise, and understanding the basics can help you assess whether a settlement offer is fair.

The starting point in most rights of light compensation claims is something called the "diminution in value" of your property. In simple terms, this means the reduction in your property's market value caused by the loss of light. A surveyor will assess what your property was worth before the obstruction and what it is worth after. The difference between those two figures forms the baseline of your claim. If you are unsure about what a right of light is or how it can be infringed, it helps to get familiar with the fundamentals first.

However, diminution in value is often just the floor, not the ceiling. Courts have recognised that where a developer has knowingly infringed a right of light, the affected property owner may be entitled to a share of the developer's profit from the offending development. This principle comes from the landmark case of Tamares (Vincent Square) Ltd v Fairpoint Properties (No 2) Ltd [2007], and it has shaped how negotiations play out ever since. The idea is straightforward: if someone profits by taking your light, you should get a slice of that profit.

In practice, most valuations use a method that blends both elements. A rights of light surveyor will model the loss of light using technical tools like the Waldram diagram, which maps how much sky visibility each window loses. They then translate that technical loss into a financial figure. The surveyor considers factors like the size of the room affected, the use of the room (a bedroom matters differently from a storeroom), and the overall impact on the property. You can find more detail on how compensation is calculated across different types of claim.

The developer's profit margin on the scheme also plays a significant role. If a large commercial development generates millions in profit and your lost light made that scheme possible, the compensation figure can be substantial. Surveyors will typically look at the gross development value of the project, subtract costs and a reasonable profit margin, and then assess what proportion of the remaining profit is fairly attributable to the infringement of your rights. This is sometimes referred to as the "negotiating damages" approach, reflecting what a willing buyer and willing seller would have agreed in a hypothetical negotiation before the development went ahead.

One common misconception is that compensation is always modest. In central London and other high-value areas, rights of light settlements regularly reach five or six figures for a single property. Even in suburban settings, claims can be worth more than people expect, particularly where multiple rooms are affected or where the property is used for commercial purposes.

It is also worth knowing that the court's approach differs depending on whether the claim is brought before or after construction. Before building work starts, you have stronger leverage because the court can grant an injunction to stop the development entirely. After completion, the court is more likely to award damages instead. The timing of your claim therefore has a direct impact on the valuation outcome. If you want to understand your legal rights as a property owner, acting early almost always puts you in a better position.

The key statutes underpinning these claims are the Prescription Act 1832, which establishes the 20-year rule for acquiring rights of light, and the Supreme Court Act 1981 (now the Senior Courts Act 1981), which gives the court discretion to award damages in lieu of an injunction. The leading case on when damages should replace an injunction remains Shelfer v City of London Electric Lighting Co [1895], though more recent decisions like Coventry v Lawrence [2014] have given courts greater flexibility.

If you have received an approach from a developer or suspect that a nearby scheme may affect your light, getting an early valuation from a specialist surveyor is one of the most useful steps you can take. You can request a free assessment to find out where you stand and what your claim might realistically be worth. Every property is different, and the figures depend heavily on the specific facts, but knowing the methodology puts you in a much stronger position from the outset.

Reference: Tamares (Vincent Square) Ltd v Fairpoint Properties (No 2) Ltd [2007] EWHC 212 (Ch); Shelfer v City of London Electric Lighting Co [1895] 1 Ch 287; Coventry v Lawrence [2014] UKSC 13; Prescription Act 1832; Senior Courts Act 1981 s.50