Side Returns Extensions: Everything you need to consider

Side return extensions are ideal to transform narrow and dark back rooms into light and airy living spaces, but there's lots to consider, take a look at our guide!

A side return on a very modern property

Side return extensions are ideal to transform narrow and dark back rooms into light and airy living spaces. There’s lots to consider when it comes to extending your home in this way… have you thought of the following?
A large side extension with kitchen incorporated


Every side return extension is different and so the exact price for each vary, but generally speaking, a single storey extension of this type will set you back between £1,200 - £1,900 per square metre of additional space. This figure rises dependent on the finish desired and materials required to finish it, as well as any specialist architectural intervention.

Planning permission

Most side return extensions don’t require planning permission, as Permitted Development Rights (PDRs) covers single storey extensions up to a height of four metres (unless it sits within 2m of the property boundary, in which case it should be 3m) with a width no more than half of the original house. However, if the extension is planned to be larger or taller than this, or the property is situated in a conservation area, AONB or is listed, planning permission will be a requirement before development can begin.

Neighbourly permission

If a side return extension is being placed toward or with an existing party wall, on a boundary line with your neighbours or any excavation is required, homeowners will need to a written party wall agreement from the relevant neighbours before works can begin. A party wall notice can be served to neighbours by the homeowner or by a party wall surveyor, but best to keep it personal for convenience during the build. What’s more, if neighbours agree to sign a party wall agreement waiver, over £1,000 could be saved.
A light and airy extension using sky lights

Light incorporation

The loss of a side window when investing in a side return extension can make the room seem darker than it was before. Clever interior design and colour scheming can help bring light to the room, as well as the installation of a skylight or large glass doors. Pale colours, reflective materials, pale stone flooring or high gloss splashbacks can all bring a lighter feel. With skylights or roof windows, opting for choices that don’t need to open (for example if the doors are likely to be opened frequently and so ventilation will already be sufficient) will save money.


A consistent flooring finish throughout the new extension will make the new room feel as large as possible; blending it seamlessly in to the existing house. To further extend the feeling of space, incorporating the same floor throughout the entire ground floor and choosing an open-plan layout creates a fuss-free aesthetic. Areas of the home can be zoned using interior design techniques.

Existing architectural details

The architectural finish of a new extension can drive up the overall cost and so may be a key consideration in decisions made to adhere to a budget. If an open-plan layout is being used throughout the ground floor and the side return extension, a consistent wall finish may look best – but if the extension remains a room in its own right, differing the materials used may present a feel that’s less ‘boxy’. Any original features of the home may need to be replicated or accommodated around by the new extension and should be considered right from the conception of the extension design.
A glass side extension

Roof design

The type of roof being used on a side return extension can determine not just its exterior look but also its interior feel. A single pitch roof can add volume and make it feel loftier inside, but in some cases a flat glazed roof or rooflights can have the same impact. While some homeowners opt for a roof finish that mirrors that of on the rest the house, in some cases a totally different type of roof will look more effective and modernise the space. To match or contrast is entirely and personal choice.

Space efficiency

Access to a house with a side return extension can be tricky if the property is terraced. If the new space is of modest proportions, the interior design will need to be created with space-saving solutions in mind. Wall units should be kept to a minimum and shelving planned strategically. If the extension is being used for a kitchen, a single-line galley kitchen may be the most functional fix and worktop space should be carefully planned. If the installation of a side return extension is intended to create an open-plan layout space, the design should be created in conjunction with an interior renovation specialist who will be able to scope it out from scratch.

Access issues

Many side return extensions are built on terraced houses and so the extension design may temporarily impact access to the home. Some terraced homes will only permit certain construction methods and it is often wise to make arrangements with neighbours to ensure access is available throughout the build process. This may involve the removal of fencing panels between gardens or using their land for short-term storage. 
A kitchen extension in side return

Project management

Building a side return extension can be a large project with many involved parties, project variables and areas of interdependency. Ideally, such a project will be overseen by a specialist project manager who can manage all aspects of the job and keep everyone up-to-date, on-schedule and to budget. Thorough and professional project management can help lessen the stress on the homeowner and ensure a high quality finish throughout. Refresh Renovations designate a dedicated project manager to each side return extension job exclusively, so all is taken care of by an expert.

Get in touch!

Side return extensions can be completed in just weeks if managed professionally and worked on by tradespeople, architects and project managers with expertise in such jobs. Get in touch with Refresh today to see how we can help you with your side return extension project.

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