Rear extensions

Rear extensions are one of the most popular type of extensions in the UK. As house and land prices continue to rise, many people are choosing to remain in their existing home and build additional living space at the rear of their property.


Many homeowners like the area they live in and don’t want to move, but need more space for their growing family. Others may not be in a financial position to move to a larger property.

If your family is growing and you need more space, then a rear extension is a perfect solution to your problems without the need to move house.


Fittra offers a comprehensive building service for homeowners in London and across the UK who want to expand the living area of their home. Our expert team of design, planning and engineering consultants will guide you through the entire process, from start to finish.

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Can you extend back of house UK?

One of the reasons that rear home extensions are so popular is that planning permission is not usually required, provided the proposed plans meet certain requirements and are covered within the permitted development rules.


Whether you live in a detached house in the suburbs, or a Victorian terraced house in London, you are able to take advantage of flexible planning rules to extend your property and increase the living space of your home.


Building an extension at the rear of your house can completely transform your living space. Many homeowners opt to create an airy, open plan living area, with an open plan kitchen and bi-folding doors leading out to the patio and garden.

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How much does a rear extension cost UK?

A rear house extension cost will depend on a variety of factors. The prime factor will be the size of the build. A small rear extension to a terraced house will cost significantly less than a large addition to a detached family house.


The cost will also be determined to a large extent on the client’s individual specifications for the build. A more complex architectural design, with higher-end finishes and materials will cost more than a more straightforward build project.


Location is also a relevant factor. The cost of rear extension London is the highest in the UK, whereas in other parts of the UK the cost will be less. However, any building addition which increases the area of the internal living space of a home is a good investment. The increase in the value of the property will far exceed the cost of the building work involved in a rear extension, adding immediate equity to the value of your home.


Fittra works with clients with all types of budgets and specifications. We offer transparent and competitive pricing, and agree detailed cost estimates with the client before commencing each project.


Whatever your budget and requirements, we will work with you 24/7 to ensure that we design and build an addition to your home that is perfectly suited to your needs, and you will be 100% satisfied with.


The team at Fittra take great pride in our service, workmanship and attention to detail. As a result, the majority of our clients come to us through referrals.

How far can I extend the rear of my house?

Under so called permitted development rights, a rear extension can be added to your existing property without the need for planning permission, provided the following rules are adhered to, which can be summarised as follows:

  • the new addition must not extend more than 3 metres from the rear of the existing property (4 metres for a detached property)
  • the extra space must not exceed 50% of the area of the existing house
  • the extension must not be more than 4 metres in height
  • in the case of a double storey rear extension, there must be at least 7 metres remaining of garden from the end of the property

Under new rules introduced in 2021, an extension can be pushed out to 6 metres (8 metres for a detached property) under a neighbourhood consultation scheme.

It is essential that you work with a construction company who understands the rules relating to rear extension planning and can produce a set of plans which both adhere to these rules and meet your requirements.

If you are looking for back of house extension ideas, then contact Fittra for a free consultation. Our NHBC-registered firm has an in-house team of architects and planning consultants who can guide you through the whole process.

If you have a vision of how you would like to extend your home, then we can help you make your vision become a reality. Contact us today!

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Interested in rear extension?


Why Work With US

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Do you have questions?

Frequently Asked Questions

What is a rear extension?

A rear extension extends from the rear of your house into your garden space, whilst a side return extends the width of your property, utilising the dead space down the side of your home.

Do I need an architect for a small extension?

For a full planning application you will need professional architecture drawings, so the answer would be Yes. Your architect should be able to create your more detailed building regulations drawings, and instruct a structural engineer on your behalf.

What size extension can I build without planning permission?

Rear extensions tend to have the least amount of red tape associated with them and in most cases, you should be able to build a single storey extension of up to four metres for a detached house, or three metres for all other types of house, without the need for planning permission or prior approval.

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