Why Councils refuse planning permission for two-storey side extensions, and often lose at appeal

Just Planning receives hundreds of enquiries every year from householders who have been refused planning permission for extensions to their home.

A number of these are for the most common form of householder development – the single-storey rear extension. The government extended permitted development rights for ground floor extensions in 2013 (allowing extensions with a depth of up to 6m or 8m, subject to a prior approval application) and renewed that right in 2019, but some Councils still refuse permission for any extension of more than 3m.

Another popular type of appeal relates to dormer loft extensions. Growing families need extra bedrooms, and the loft is a large area of unused space. Large dormers are possible under permitted development, but some houses (and all flats) do not have permitted development rights and Councils generally refuse applications even though they would be permitted development in slightly different circumstances. Dormer loft conversions are our biggest source of enquiries when it comes to Enforcement Notices – many homeowners build a dormer in good faith, believing it to be permitted development, and are later asked by the Council to demolish it. Read more about dormers and enforcement here.

However, the biggest growth in enquiries in recent months has been in relation to two-storey side extensions. Councils have increasingly decided that these should not be allowed. Some Councils – the London Borough of Richmond and the Royal Borough of Kingston seems to be the worst offenders – are particularly keen to refuse most applications of this kind.

As a general rule, Council planners dislike alterations that are visible from the front (dormers and ground floor rear extensions are almost always hidden from the street) and two-storey side extensions are therefore unpopular with them.

Councils generally require that side extensions are set back from the front elevation (typically by 1m) with the ridge of the roof set lower than the ridge over the main house. This helps ensure that the extension is a subservient addition to the house, not overwhelming its original character and appearance.

However, Councils also reject side extensions in principle, sometimes arguing that they unbalance a semi-detached pair, or that they lead to a ‘terracing effect’ where side extensions may give the impression of a terraced row.

Sometimes these concerns are justified and it is always important that your extension is carefully designed. However, often the Council’s position is not backed up by up to date local policy and guidance and is an overly strict approach to this form of development.

Councils can be particularly stubborn when it comes to a form of development they just don’t like. 

The London Borough of Richmond recently refused planning permission for a two-storey side extension. We acted for the homeowner and won the appeal, pointing out that a large number of houses on this street had a similar type of extension. Some time later, one of his neighbours (on the same street) applied for the same type of extension, pointing out that our appeal had been successful. The Council refused this application as well. We also appealed for this owner and also won this appeal. It is a clear principle of planning practice that Councils should adapt their decision making in light of appeal decisions.

If you have been refused planning permission for a two-storey side extension, send us a copy of your decision (or email us the planning reference number and your address) and we will review your plans and the Council decision and give you free, honest advice on your chance of success at appeal. Our email address is: info@just-planning.co.uk.

If you are interested learning more about householder planning (planning applications and permitted development), check out Martin Gaine’s book, How to Get Planning Permission – An Insider’s Secrets.