Rear Extension vs Side Extension: Which Is Right For Your Property?
If you are thinking about extending your home, one of the first decisions you will need to make is where the extension should go. For most properties, the two most practical options are a rear extension or a side extension, and choosing between them is not always straightforward.
The right answer depends on a range of factors specific to your property, including its layout, the size of your plot, your planning constraints and what you are hoping to achieve with the additional space.
Here is a clear comparison to help you decide.
Rear Property Extensions
A rear extension is built onto the back of the property, extending into the rear garden. It is the most common type of single storey extension in the UK and is particularly popular for creating larger kitchen and dining areas, open plan living spaces and garden rooms that connect the interior of the home to the outdoor space beyond.
Because rear extensions extend into the garden rather than along the side of the property, they are well suited to houses with a reasonable depth of garden and work particularly well where the rear of the property faces south or west, bringing natural light into the new space throughout the day.
Side Property Extensions
A side extension is built onto the side of the property, typically making use of the gap between the house and the boundary of the plot.
This gap (sometimes referred to as a side return) is a feature of many terraced and semi-detached properties where a narrow strip of land runs alongside the house between the building and the fence or wall at the edge of the plot.
Side extensions can be used to widen an existing room, create a new room at ground floor level or, when combined with a rear extension in a wrap-around design, dramatically increase the overall footprint of the ground floor.
How Do They Compare?
Impact On The Garden
The most significant practical difference between a rear extension and a side extension is the impact on the garden. A rear extension reduces the depth of the rear garden, which may be an important consideration if outdoor space is something you value or if you have children who need room to play. The larger the rear extension, the more garden space is consumed.
A side extension, by contrast, uses the side return rather than the main garden area. This makes it a more attractive option for homeowners who want to add space without significantly reducing their usable outdoor area, particularly on plots where the rear garden is already compact.
Planning Permission
Both rear and side extensions may or may not require planning permission depending on their size, height and the specific permitted development rules that apply to your property.
As a general guide, single storey rear extensions of up to four metres on a detached house and three metres on a semi-detached or terraced house may fall within permitted development, whilst side extensions that extend beyond half the width of the original house typically require a formal planning application.
It is always advisable to confirm the planning position with your local authority or an experienced builder before committing to a design, as permitted development rights can be restricted in conservation areas, on listed buildings and on some newer housing developments where permitted development rights have been removed by condition.
Structural Considerations
Both types of extension require a sound structural design, but side extensions in particular can present specific challenges where the side return is narrow or where the existing wall of the house needs to be opened up to integrate the new space.
The proximity of the neighbouring property on a semi-detached or terraced house also needs to be carefully considered in the design of a side extension, and Party Wall Act obligations may apply where the work is close to or on the shared boundary.
Which Adds More Space?
In most cases, a rear extension will add more usable floor area than a side extension on the same plot, simply because there is typically more room to extend at the rear than along the side of the property.
However, combining a side and rear extension in a wrap-around design can deliver the largest possible increase in ground floor space, effectively maximising the footprint of the property in both directions at once.
Which Is Right For You?
If maximising the size of the new space is the priority and you have sufficient garden depth to accommodate it, a rear extension is likely to deliver the best result.
If preserving your garden is important and your property has a useful side return, a side extension may be the more practical and less disruptive option.
Where budget allows and your plot permits, a wrap-around extension combining both approaches will achieve the most significant transformation of your ground floor.