Broadly speaking the construction of an extension or conservatory does not require planning permission when it is to the rear of the house.
The following information should be taken as general guidelines only;
- Terraced and Semi-Detached Houses: If the house has not been previously extended then the floor area of the proposed extension cannot exceed 40 sq metres. This exemption also allows for extensions above ground-floor level (if the house is semi-detached or terraced, the area of the above ground extension cannot exceed 12 sq. m). This means, for a typical semi-detached house, one could have a ground floor extension of 28sq. m & 2nd floor extension of 12sq m without applying for planning permission. Any above ground floor extension shall be a distance of not less than 2 metres from any party boundary.
- Detached Houses: As with terraced and semi-detached dwellings, the overall area of an extension must be less than 40 sq. metres. This exemption also allows for extensions above ground floor level, the area above ground floor cannot exceed 20 sq. m. One could therefore have a ground floor extension of 20 sq. m., and a 2nd floor of 20 sq. m. Any above ground floor extension shall be a distance of not less than 2 metres from any party boundary.
- Both Cases: If the proposed extension is in addition to an existing extension (post 01-10-1964), the overall area of all extensions must not be more than 40 sq. meters.
The extension shall not reduce the “Private Open Space” of the back garden to less than 25 sq. m. Hard surface areas to the rear of a house are exempted development, providing they are used for a purpose incidental to the enjoyment of the house and not used for the parking of cars.
The following points relate to the height one can build my extension without permission required?
- The highest point to which the wall of an exempt extension can be built is eaves level;
- If the proposed extension has a flat roof, it must not exceed the eves or parapet level;
- If the proposed extension has a pitched roof, it must not exceed the ridge of the existing pitched roof.
Can I build a window to the side of my extension?
Yes, providing the following guidelines are applied;
- Terraced and Semi-Detached Houses: Windows at ground floor level shall not be less than 1 metre from the boundary they face. Windows at above ground floor level shall not be less than 11m from the boundary they face. The above applies to terraced and semi detached dwellings.
- Detached Houses: Where the dwelling is detached and the floor area of above ground floor extension is greater than 12sq meters, the windows shall not be less than 11m from the boundary they face.