A Right to Light Assessment determines the interrelationship between a proposed building, or extension, and those protected apertures (normally windows) on buildings surrounding it to establish whether overshadowing will affect the natural daylight levels received. This phenomenon can create amenity issues, which can ultimately lead to legal challenges from neighbours due to the reduction of natural light through a protected window, costing you time and money to resolve. To find out more about how right of light is assessed, click here.

When is a Right to Light Assessment required?

A window may acquire a Right to Light in several different ways, but the most common is through prescription, under the Prescription Act 1832. Rights to light are often acquired after 20 years of uninterrupted light to a window. Once this right has been acquired, the owner is entitled to ‘sufficient light according to the ordinary notions of mankind’, but this does not mean that they are entitled to completely unobstructed light. Our bespoke software has the capability to model the effects upon protected windows so you’ll know the impact of your development, and thus can make informed design choices that will avoid legal challenges.

How is Right to Light assessed?

More information about our bespoke modelling can be found here. The overall outcome of the report will show you whether your development would create an acceptable impact in accordance with the legal precedent. Typically, this means at least 50% of the assessed room should be able to see at least 0.2% of the sky, increasing to 55% for a residential properties. If the development does not meet this criteria, we will provide recommendations on how best to progress your project.