Permitted development: what is it and what extension projects does it cover?
As many of you will already know, not all external home improvement projects require planning approval in order to be lawfully carried out. Under the remit of ‘permitted development’, all kinds of improvements can be made to your home without seeking permission. This list includes many types of extension, provided you live in a semi detached or detached home that is not in a designated area and is not a listed building.
If you’ve been thinking about extending your home but have been put off by the idea of a planning application, here are some home improvements that probably won’t need one…
Single storey rear extension
Planning laws allow the most leeway under permitted development with rear single storey extensions. This is because of their low profile as well as the fact they protrude from the back of your home, meaning they are unlikely to be visible from, or obstruct the view of, any neighbouring property.
In order to be permissible, extensions and outbuildings must not exceed 50% of the area of ‘original house’, so the size of any previous extensions must be taken into consideration. For new properties, ‘original house’ means the house when it was first completed. For older properties, it means the house as it stood on 1st of July 1948.
Other stipulations for a rear single storey extension include that is must be composed of materials similar in appearance to the rest of the home and that if the extension is within two metres of a boundary, then the maximum height of its eaves should be no more than three metres.
Traditionally, a single storey extension should not extend more than three metres from the original rear wall of the property of an attached house, or four metres if it is detached. However, this limit has been increased to six and eight metres respectively until 30th of May 2019, under a programme called ‘The Neighbourhood Consultation Scheme’.
Two storey rear extensions
Two storey rear extensions have some restrictions in place if they are to be constructed under permitted development. This is because the additional height may block out a neighbour’s natural light, or windows on your new second floor could create sight lines that encroach on a neighbour’s privacy.
The same rules regarding 50% of the original house and the use of appropriate materials still apply but, in addition, your new extension must not be any higher than the existing house. Also, if the extension is within two metres of a boundary, it must be no more than three metres in height.
Furthermore, two storey extensions are not allowed to protrude more than three metres from the original rear wall of the property, and, under Permitted Development provision, they also can’t be within seven metres of any boundary opposite the rear wall. Finally, to protect your neighbours’ privacy (and possibly your own!) any windows on the upper floor in a side elevation need to be obscure glazed and non-opening if they are more than 1.7 metres above the floor of the room. You’re also not allowed to install balconies or verandas without planning permission for the same reasons of privacy.
Side return extensions
The side return is a much-maligned feature commonly found on Victorian terraced and semi detached houses. This is where a narrow strip of garden runs down one side of the property, presumably at some point in time this gave the property a small private area for an outside toilet. These days, however, they tend to be small, shaded spaces with few practical applications, which makes them perfect candidates to be converted into more useable spaces.
In order to adhere to permitted development, many of the same stipulations apply. So any extension must not exceed more than 50% of the area of the original home, be no higher than three meters if within two metres of a boundary and so on. Additionally, a side extension can only be a single storey and must not be any wider than half the original width of the building.
Before you start...
So despite what many think, it’s not just rear conservatories that you can build under permitted development. You can, in fact, carry out a range of substantial extensions by using this useful bit of legislation.
Whatever extension you’re considering, you should speak to an expert before carrying out any external improvements, just to be completely certain that you’re not breaching any planning laws. Especially if you live within a designated or conservation area, where local bylaws may have been put in place, it’s always better to be safe than sorry.