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Think of the neighbours

In the Department’s experience, neighbour disputes arising from house extension proposals can often be difficult to resolve. Careful thought about how you develop, and early discussion with your neighbour could prevent some of these difficulties.

Although not mandatory, and failure to follow them cannot be used by as a reason to object to proposals, you may wish to consider whether the tips below would be helpful to carry out.

Before you start work

Let your neighbours know about what work you intend to carry out to your property; they are likely to be concerned about the work, which might affect them. You may also be able to meet some of your neighbour's worries by modifying your plans. If you do need to make a planning application for your proposal the Department will advertise the planning application in the press and via site notice. This will give your neighbours the opportunity to express their views. This could potentially delay your application and cause you to change your plans anyway.

Most work will also need approval under the Building Regulations.

Assessing the impact of an extension

A poorly designed extension can detract from the appearance of your home and the street scene and can also have a detrimental impact on neighbouring properties, including overshadowing.

Will it cause overshadowing?

Overshadowing occurs when an extension is in such a location or of such a size that it unreasonably shadows a neighbouring dwelling or amenity space. The extent of overshadowing will depend upon the orientation, size and difference in ground level. In designing an extension to a building it is important to look at the impact on nearby buildings. Two-storey rear extensions close to a boundary can sometimes have a significant impact upon a neighbouring dwelling and amenity space, with a potential to overshadow them and dominate their outlook. The Department may therefore exercise planning control to limit the projection of the extension, in order that adjoining properties will be protected from excessive overshadowing. Properties directly to the side of a large rear extension may be particularly vulnerable to overshadowing and loss of light - sometimes it may be possible to overcome some of this effect by using a shallower roof pitch or a ‘hipped’ roof rather than a gable.

Will the extension overlook neighbouring properties?

Retaining privacy is an important consideration when designing an extension. Overlooking occurs when there is inadequate distance between windows in the proposed extension and a neighbouring property's window, so that privacy is infringed. Windows (except for some high level or fixed obscure glazed windows) should not normally be incorporated in a wall that is next to a shared boundary, as this may result in overlooking and a loss of privacy for neighbours. First floor windows on side or rear walls may in particular result in overlooking of neighbouring properties. Careful attention should be paid to any potential loss of privacy.


Balconies are great when you are on holiday but at home can create the potential for serious overlooking and privacy problems. Think carefully and discuss with your neighbours before suggesting such features.

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