Planning Permission for Extensions
Some extensions and renovations can be made to houses without planning permission in what is referred to as Permitted Development.
For an extension to be classed as ‘Permitted Development’ there are a few stipulations to consider:
The maximum footprint of the extension or garden room must be less than half of the land around the house as it stood in 1948 with a maximum height of the extension of 4m – this reduces to 3m if the extension reaches within 2m of your boundary. The maximum length of a rear single-height extension is 3m from the back of the house for attached properties if the residence is detached this is then 4m. If the extension is two storeys the maximum length is 3m.
Side extensions cannot exceed more than half the width of the house. Roof extensions cannot add more than 40 cubic metres of space to a terraced house or 50 cubic metres to a detached or semi-detached house.
Basements are usually permitted if the work is converting an existing cellar or basement, as long as it is not going to be used for self-contained accommodations and doesn’t change the exterior appearance of the building.
Planning Permission for Garden Rooms
Garden Rooms are also usually permitted depending on size and location and as long as you are not creating a self-contained accommodation.
This only applies to houses, not flats or maisonettes and some properties in areas with conservation orders will have different rules. If planning permission is needed it is useful to get pre-application advice from your local authority to highlight any potential issues with your application. Elements of frameless glass and frameless assemblies are usually favoured due to the transparent nature of glass, there is minimal overshadowing to neighbours and it maintains the original design of the building.
The Royal Town Planning Institute recommends discussing any plans with neighbours and to check the previous planning applications made on the property, it could give you some useful insight into what may be rejected and the reasons as to why.
Any project designed by an architect will have a much greater chance of gaining planning permission if it is needed and will be able to advise on what designs would be more sympathetic to the surrounding buildings.