If your extension doesn’t need full planning permission, then it is a Permitted Development, as long as certain constraints are observed:
Cladding of the outside of a home using stone, pebble, render, timber, tiles or plastic is not a PD on designated land (areas of outstanding natural beauty).
Extensions should not exceed 50% of the land around the existing property. Remember to include sheds etc in your calculation of this limit.
If the planned extension is proud of the front or side elevation and facing a road, then it will not be a PD.
Side extensions are not permitted on designated land.
The choice of materials for exterior development should match the existing house, although this is not necessary with a conservatory.
A side extension must not be wider than half the house width.
Your side extensions can be one storey, up to four metres high.
PD Rules allow a maximum eaves height of three metres if the extension is close to the plot boundary (within two metres).
Your single-storey rear extension can extend back from the existing property by up to3 metres, for a terraced house – or 4 metres for a detached house. If it is not designated land or a site of Special Scientific Interest, you can go up to 6 or 8 metres for terraced and detached houses respectively(until 30th May, 2016.) However the neighbour consultation scheme applies to these increases.
PD Rules allow a maximum height of 4 metres for single storey rear extensions.
The ridge and eaves height for an extension cannot be higher than the original property.
Do you need HELP WITH YOUR SINGLE-STOREY EXTENSION &