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Do I need planning permission for my house extension?


Planning Permission for an extension is not always required. In some cases, a single-storey extension (and even some two-storey extensions) are allowed under permitted development rights. If this is the case for your extension, you won’t have to make a planning application, although a Certificate of Lawful Development is recommended. To be classed as Permitted Development, your extension will have to meet a range of criteria relating to its size, height, materials, location, and orientation.

When Do I need Planning Permission for my extension?

You will usually need planning permission for an extension, if:

  • Your extension will cover more than half the area of land your home sits within.

  • It will be higher than the highest part of your existing roof, or higher at the eaves than your existing eaves.

  • The height of the eaves will exceed three metres and your extension will come to within two metres of the boundary.

  • If it is to be built forward of your main elevation of the house, or will front a highway.

  • A veranda, balcony or raised platform is included.

  • There is to be a new microwave antenna, such as a TV aerial on your extension.

  • Your house extension will have a chimney, flue or soil and vent pipe.

  • Work will include alterations to the roof of the existing house.

Single-Storey extensions and permitted development

In the case of your single-storey extensions, permitted development only applies, if:

  • Your new structure extends beyond the rear wall of your original house by less than four metres for a detached house, or more than three metres for any other house or, in the case of your extensions not in a designated area (such as a Conservation Areas) or a Site of Special historical or scientific interest and, subject to Prior Approval, will be less than eight metres if detached or six metres for any other house.

  • Does not exceed four metres in height.

  • Materials used are similar to those on the existing house.

Two-storey extensions and permitted development

In the case of two-storey extensions, permitted development only applies, if:

  • Your extension does not extend beyond the rear wall of your original house by more than three metres or will lie within seven metres of any boundaries opposite the rear wall of the house.

  • Your roof pitch matches that of the existing house as much as possible and practical.

  • Any windows on your upper floor on a side elevation are obscure-glazed and non-opening (unless your openable section is more than 1.7m above floor level.

  • Materials used are like those on your existing house.

In addition, all side extensions of more than one storey will require householder planning permission.

Gibbons Construction Management will be releasing an article shortly with a guide to party walls, It is a must-read for those living in terraced or semi-detached houses.

For more information. Please visit our main website or get in touch to arrange a free consultation.

Gibbons Construction Management

Build | Extend | Renovate | Repair

Tel: 01617103349

Mobile: 07940195544

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