The 45° Code is a measure used around the West Midlands by most councils (including Birmingham City Council) and Calthorpe Estates to ensure that any extension work done to a house does not impinge on your neighbours’ outlook or access to light.
This issue most often affects homeowners wanting to build rear extensions on semi-detached and terraced houses, but can also apply to side extensions too.
The Code is designed to provide a fair balance between the wishes of the property owners who want to build and improve their homes and the ‘right to light’ of the people living in the neighbouring properties by protecting the outlook from the rooms of the neighbouring properties and to guaranteeing daylight into them. It is also designed to take into consideration differences in ground levels, where needed.
Councils apply the code by ensuring that any new building work proposed – whether single or double storey – does not cross an imaginary 45° line drawn from the middle of the nearest front or rear window of the neighbouring accommodation that might be affected by the new extension.
A window you take the measurement from must be the main source of light to a ‘habitable room’ such as living rooms, bedrooms, kitchens and conservatories but not bathrooms, utility rooms, halls, landings or garages, as people generally don’t spend a lot of time in these rooms.