You will be glad to hear that you don’t need planning permission to build a garden room, as long as it meets the following requirements:
The area covered by the garden room is not bigger than half the total area of the original property. If you have other outer buildings that were not part of the original house, then you will need to take this into consideration.
The garden room cannot be taller than the highest part of the existing house. The maximum height is 4m.
The eaves should not be higher than the eaves of the existing house. The maximum height of the eaves is 2.5m.
Any part of the garden room cannot extend beyond any wall facing a road.
The garden room is used for domestic purposes only.
It is also good to note that if you live in a conservation area, it is likely you will need consent to go ahead with any sort of extension. New build developments may also have restrictions in place, so be sure to check with your local authority or double-glazing expert!