Extensions Question

Gap between single storey extension and neighbour's extension

We are currently planning a rear single storey extension to our semi detached property. The attached neighbours have already done this leaving a 150mm gap from the boundary. I need advice on how far I should leave in between the 2 extensions. Should I also leave 150mm which means there wouldn't be room for maintenance access or should I leave more and how much? The bigger the gap we leave the less space we will have inside the new extension.

3 Answers

Best Answer

The better solution would be to join the extensions together, thus eliminating the gap altogether. This is a party wall issue and therefore you would have to discuss this with your neighbour first and get a written agreement in place.Hope this helps. Paul

Answered 26th Aug 2014


Member since 13 Jun 2013

I agree with the last two comments, however having a 150mm gap between extensions is quite common but also depends on your neighbours external finish of the boundary wall. If their wall is rendered, if it fails in the future, they will not be able to repair it thus causing damp. If it is facia brickwork or dense concrete block wall, this should not require as much attention. If you decide to have a gap, your boundary wall should be constructed using dense concrete blocks or brickwork.

Answered 28th Aug 2014

SD Building Plans

Member since 14 Dec 2012

Small gap between extensions can cause problems. If possible it would be best to join the extensions together. You would need written permission from your neighbour as this would be come a party wall issue. If your neighbour is agreeable the planning office and building inspector will need proof of this.

Answered 26th Aug 2014


Member since 29 May 2014

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