Class 1 exempted development (S.I. No.600 of 2001) allows a home-owner to extend their house up to 40 square metres without planning permission so long as the extension is single storey off the back of the house.
In addition a semi-detached or terraced house can be increased with a 12 square metres first floor extension while a detached house can be increased with a 20 square metres first floor extension without planning permission. In both cases the first floor extension is incorporated into the overall 40 square metres exempted development mentioned above.
The extension will require planning permission in the following situations:
- When the extension can be viewed from the front of the house
- Less than 25 square metres of free space remains in the garden after the extension is completed.
- If the house already has a converted attic or garage which, when combined with the proposed extension off the back, will exceed an overall area of 40 square metres.
Further information is available during the preliminary conversations of our Design Service. If you have any doubts regarding planning permission you should contact your local planning authorities.
