David Ryland, UK Structural Engineer, designs property, home & house extensions

The Institution of Structural Engineers
David Ryland
I.Eng. A.M.I.Struct.E.
Structural Engineer
TRADA member

Limited Guidance Notes on Extensions

Section A - Permitted Development

1. You are allowed to build some extensions without planning permission, providing they conform to certain requirements laid down by the Department of the Environment † and the Local Authority for the area.
2. These extensions are classified as 'Permitted Development'. They must have a volume under a certain percentage of the original house. The percentages vary depending on the type of house, such as terraced or detached. Certain existing buildings on the land, such as detached garages or stores may detract from this allowance if they are closer to the extension than the regulation limit.

3. Previous extensions will also detract from this allowance.

4. There are other restrictions relating to the distance from a boundary and the height of the roof along the boundary to which the extension is allowed to be built.

5. There are also restrictions relating to the proximity to a highway and in certain cases, to footpaths which may pass the property adjacent to the boundaries, sometimes at the rear.

6. Deciding if an extension is classed as 'Permitted Development' can be complicated and to proceed on incorrect, although well meant advice can lead to the Local Authority issuing a demolition order in extreme cases, or you may be required to apply for planning approval retrospectively, which may not be granted without alterations.

7. Sometimes these issues do not come to light until a solicitor carries out a search when you are in the middle of negotiations to sell your property. The ensuing delay can lead to a lost buyer.

8. To safeguard against mistakes and to avoid complications when selling it is advisable to apply to the council for a 'Certificate of Lawful Use'. You will need to supply drawings with the application but the Local Authority charge is normally only half of the full planning fee. The Council will check your proposal against the regulations and if it conforms, issue you with the document.

9. Confirmation of approval usually takes four to six weeks to come through.

10. Some houses have covenants applied to the original planning application by the local authority which remove all or some rights to permitted development.

References: † See 'Planning, a guide for householders' available from www.communities.gov.uk.

Contact details:
Email: david@extensions4homes.co.uk
Tel: 01953 853040
Mobile: 07802 183823

 Guidance Notes on Extensions 

 Permitted Development 
 Planning Permission 
 Building Control 
 Foundation Engineering 
 The Builder 

Sample drawings
Planning:   Drawing1   Drawing2 
   Drawing3   Drawing4 
Building Control:   Drawing1   Drawing2