Much will depend on the location of the building within your property.
Under current regulations outbuildings are considered to be permitted development, not requiring planning permission, provided all the following conditions are met:
Outbuildings are not permitted forward of the principal elevation of the original house
Outbuildings and garages must be single storey with a maximum eaves height of 2.5 metres and maximum overall height of 4 metres with a dual pitched roof - or 3 metres for any other roof
If the outbuilding is within 2 metres of the property boundary the whole building should not exceed 2.5 metres in height
Outbuildings and other additions must not exceed 50% of the total area of land around the original house. Sheds and all other outbuildings and extensions to the original house must be included when calculating this 50% limit
In National Parks, the Broads, Areas of Outstanding Natural Beauty and World Heritage Sites the maximum area to be covered by any outbuilding more than 20 metres from the house must not exceed 10 square metres.
If you have a listed building any outbuilding will require planning permission.
As all of this can be a bit daunting, why not take advantage of our Planning Application service? Let our experienced team prepare and submit the application for you, along with plans of the ground levels and scale drawings that are required.