subject: The 45 Degree Rule [print this page] The 45 degree rule is all about the Right of Light. It usually involves a line from the mid-point of a window sill, which is potentially affected by a neighbours extension, at a 45 degree angle towards the extension/development. If the proposed development crosses this line then it will usually be deemed unacceptable.
There may be a few grounds for exepemption from the rule, where semi-detached or terraced houses may be involved, where a development may be sited forward of the possible affected window, and this would allow more light to reach it, the 45 degree rule may be relaxed a little.
Sometimes on new housing projects, the landowner will incorprate restrictive obligiations which enable the developer to build wherever, but limit the house owner. For example if you buy a house on a development site, and a new house is built blocking/interrupting the light to your windows then you may not be able to fight it.
If you contact your local council's planning or building department they should be able to provide you with any information regarding this matter.
A Right of Light is protected in England and Wales under common law, adverse posesion or by the Prescription Act 1832. It must be acquired before it can be enforced.
If a window has received over 20 years of unobstructed daylight then it automatically earns itself a Right of Light. Rights such as this one are for Land Registration purposes, they are valid whether or not they are registered on the title deeds for the property which claims the right.
