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How Close to my Boundary can I Build an Extension?

22 August 2019
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Eugene Kim

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There are many factors to consider prior to building an extension on your property and before you start any building work these must be checked.

An extension to your home is normally classed as ‘Permitted Development’ and fall under various categories.

Conditions to Build an Extension Under Permitted Development

You cannot have more than half of your land on the property to have additional buildings.

That the new extension goes higher than the highest part of your roof or structure.

The maximum height allowed for a single story extension is of no more than four meters.

If you are building a structure of more than one story you cannot pass three meters beyond the original rear wall of the property.

Single story extensions to the side of your property to be no more than four meters in height and no wider than half the original size of the property.

For those building a double extension on their property, you cannot go closer than seven meters to the boundary.

Any pitch on the roof that is higher than one story must match the existing pitch on the property.

Under permitted development you cannot add balconies, raised platforms or verandas.

How Close Can I Build to My Neighbours Boundary UK?

If you are planning on building an extension of more than one story you cannot go beyond the boundary at the rear by more than 3 meters.

This only applies when there is no other property on the land to the rear of your your home.

The side boundaries can be built up to but you may need to factor in other considerations.

You cannot breach the boundary in plan and in what we call elevation, this factors in the 45-degree rule that most planning officers use.

With this, they take the closest window to your build on your neighbour’s property and if it breaches the ‘imaginary line’ then planning permission can be denied.

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Minimum Gap Between Neighbours Extension

As part of your planning process, your neighbour can submit a householder planning application which voices their concerns.

As with any build, it is always worth speaking with your neighbours especially when boundaries are involved.

Let them see the plans, talk to them about heights from your build and if anything is of concern it can be rectified prior to any build which will speed up the whole process.

As a rule of thumb, a build that reaches 7.2 feet is considered acceptable and anything over that we do recommend speaking to your neighbour.

Get in Touch

Our team at Extension Architecture can help you through this process and answer any questions you may have.

You can call us on 0203 409 4215 and offer a range of services and can provide you with a free quote.

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Eugene Kim

Eugene Kim, Founder and Managing Director of Extension Architecture, has led the firm for over 14 years, consistently delivering quality solutions. His dedication has been key to the company's growth and success.

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