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Requirements for an Extension


When it comes to building an extension, or adding to your house, it is seen as a permitted development which doesn’t require planning permission – providing you follow the following limits and/or conditions:


1. It cannot be more than half the area of land around the “original house”

2. It cannot be forward of the original elevation or side elevation fronting a highway

3. It cannot be higher than the highest part of the roof

4. If it is a single storey rear extension, it cannot extend past the rear wall of the “original house” by more than 3 metres if it is attached to the house, or 4 metres if it is detached form the house

5. In addition, outside Article 2 (3) Designated Land and Sites of Specific Scientific Interest, the maximum it can be increased is 6 metres if an attached house and 8 metres if a detached house


• Please note:  these limits between 3 metres and 6 metres and between 4 metres and 8 metres are based on prior notification of the proposal to the Local Planning authority and a Neighbour Consultation Scheme. If your application received objections it may be rejected


6. If it is a single storey rear extension it cannot exceed 4 metres

7. If greater than a single storey extension it must not go beyond the rear wall of the “original house” by more than 3 metres

8. The maximum eaves height of an extension within 2 metres of the boundary is 3 metres

9. The eaves and ridge height must not be higher than the existing house

10. If it is a single storey side extension it must not exceed 4 metres in height and cannot be more than half the width of the “original house”

11. If it is a 2 storey extension it cannot be closer than 7 metres to the rear of the boundary

12. A roof pitch of an extension which is higher than 1 storey has to match the existing house

13. The materials used to build an extension must be similar to the existing house

14. You cannot have any raised platforms, verandas or balconies

15. If you have a side facing window on the upper floor of the extension it must be obscure-glaze, and the opening must be 1.7 metres above the floor

16. If it is to be built on designated land you cannot build a rear extension over 1 storey

17. If it is designated land you cannot use cladding on the exterior

18. If it is designated land you cannot have a side extension


• Please note: “Original house” means as the house stood on 1st July 1948. Although you may not have built an extension the previous owner may have

• Designated land consists of World Heritage Sites, National Parks and the Broads, Areas of Outstanding Natural Beauty and Conservation Areas

• These limitations and requirements apply to houses and not to:

1. Areas where there may be planning condition, Article 4 Direction or other restrictions that limit permitted development rights

2. Converted houses or houses created through the permitted rights to change use

3. Flats and maisonettes

4. Other building

• Please be aware also that if your extension is over 100 square metres, you may be liable for a charge under the Community Infrastructure Levy


I hope this helps in planning your extension or additional building. Once all the above has been taken into account why not click on the Contact Us for a quote.

Carpenter in Kent


Hours of work:


Monday – Friday       8am-4pm


Email: john@jbbespokecarpentry.co.uk


Telephone: 01622 92 44 69

Mobile: 07470272837


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JB Bespoke Carpentry Logo, Carpenter in Kent
Carpenter in Kent

Carpenter in Kent

JB Bespoke Carpentry Logo, Carpenter in Kent
Carpenter in Kent