An extension is a great way to add more space to your property without the need to move home. If you’re considering expanding, you may be overwhelmed by how many different types of extensions there are, and unsure where to start.

As with any type of home improvement project, the scale, cost, complexity and suitability of each type of house extension should be considered to determine which style will give you the space you need within your available budget. Before discussing your extension with an architect, it’s a good idea to have a solid understanding of the options available to you.

We’ve put together a guide to the different types of extensions, giving you a better idea of what might be right for your home expansion project.

Single-storey Extensions

Single-storey extensions involve expanding the footprint of the house downstairs only, making them one of the cheapest options.

They are often added to the back or side of a house to increase the size of the kitchen, living room or dining room, taking space away from the garden. Depending on your budget and aesthetic preference, you can opt for a flat or pitched roof, and add skylights or bi-fold doors to bring in light and make the space feel more open.

Double-storey Extensions

Double-storey extensions allow you to add space both upstairs and downstairs at the same time, offering better design continuity between the existing structure and the new addition.

While it will cost more overall, a double-storey extension is more cost-effective than a single-storey extension because the complex foundations are already factored in. You can expect to pay 50–75% more for a double-storey extension than a single-storey one.

Full-width Extensions

While many extensions are simply a small protrusion expanding one room into the garden, you may choose to extend the entire back or side of the house. This allows you to add even more space while only undertaking a single-storey extension, or can significantly increase the size of your home with a double-storey extension.

Rear Extensions

Most of the time, extensions are added to the rear of the house, as this is where there is the most available space. This also helps to preserve the overall aesthetic of the street, as the front of the building will remain the same. However, this type of extension means losing out on space in your garden.

Side Return Extensions

A side return extension makes use of the alley between your home and the neighbouring property, extending the side of your home to fill the unused space.

This type of extension is very popular because it is fairly low-cost and straightforward while still adding a decent amount of space. If your house is the right shape, a side return extension is perfect to increase the size of your home house without sacrificing your garden.

Wrap-around Extensions

Essentially combining a rear and side return extension, wrap-around extensions allow you to dramatically increase the amount of space in your home.

They are perfect for creating a spacious open-plan kitchen or adding a dedicated home office. However, the larger size and more complex construction makes this an expensive option. It also requires a lot of external space, so it isn’t suitable if you’ve only got a small garden.

Over-structure Extensions

If there isn’t any space available on the ground floor, you may be able to add an over-structure extension.

This involves building an additional storey onto a single-storey part of the house, most commonly an attached garage. By making use of the building’s existing footprint, over-structure extensions allow you to keep your garden the same size while also being more cost-effective than single-storey extensions, as they don’t require an additional foundation.

a house with an over-structure extension

Basement Extensions

Adding a basement to your home is an expensive and complex undertaking, as it requires excavation, waterproofing and ventilation, and existing pipework may need to be moved. However, in high-value property areas, or those where extending outwards isn’t possible, it could be a viable option to increase the space in your home.

If your house is positioned on a slope, you may be able to extend the ground floor and incorporate an above-ground basement beneath it, offering a more cost-effective solution.

Loft Conversions

Turning your loft into a usable room is a great way to expand the space in your home, with hip-to-gable, dormer and mansard being the main types of loft conversion.

However, not all lofts are suitable for converting. Some important considerations include the available floor space, the height and pitch of the roof, and the positioning of the stairs to the new storey. There may also be existing obstacles such as water tanks or chimney stacks that need to be moved.


A conservatory is a cost-effective way to add space to your home that usually doesn’t require planning permission.

Often made from a uPVC frame and fully glazed both on the sides and roof, conservatories are inexpensive and offer lots of light. Modern versions are better able to regulate temperature than old-fashioned conservatories, making them comfortable in both the summer and winter months.


Dating back to the 15th and 16th century when they were used for growing citrus fruits in the harsh UK climate, orangeries are essentially somewhere between a single-storey extension and a conservatory both in terms of design and price.

The differences between a conservatory and an orangery are subtle. However, an orangery usually has a solid roof perimeter with a glazed portion or roof lantern in the centre. Orangeries are often constructed mainly from brick and tend to look a little more luxurious than conservatories. 

Orangery extension with sloping windows


For instances where it’s not possible to extend out from the existing structure, you can add more space by constructing an outbuilding in the garden.

If you have enough space, this is a great option to allow for design flexibility, and is perfect for building a quiet home office space that is separate from the main house. However, outbuildings can be a complex undertaking and may require extending your home’s electrical and plumbing installations into the new addition.

Protecting your home while building an extension

Due to the risks involved with demolition and construction, your home insurer will likely reduce or remove your home insurance during your extension project. While your builder will have their own insurance in place, it won’t always be enough to cover your home and your personal liability for accidents or damage.

To protect your investment, it’s recommended that you take out specialist renovation insurance to cover your home and building works. There are lots of different types of policies, covering things such as:

  • Your home and the building works
  • Damage to the existing structure
  • Flood or fire damage to the building works
  • Property owner’s accident and injury liability
  • Transit of materials to and from the build site
  • Offsite storage, e.g. of kitchen and bathroom units

If you’re not sure what type of renovation insurance to take out while building an extension on your home, get in touch with our expert team, who will be able to advise you on the most suitable policy for your needs.

Written by Matthew Ashton

I started working in the insurance industry in 2004. Four years later, I left to focus on theological studies, working as a youth worker and then as a ministry director in Seattle, USA. When returning to the UK, I had an opportunity to work for the late Andrew Marchington. I joined his firm as a sales advisor when it had around ten staff members. Within three years, I was Head of Ops with a staff team of over 30 people. After a chance encounter in 2019 with Rachel Living and Will Cooper, I decided to co-start Stanhope and build a high-value home, luxury watch, and jewellery broker synonymous with trust. I love being with Donna, my wife, and four kids when not working, cramming in the odd row, or running when I can. I am fortunate to love what I do and consider it a blessing to grow the Stanhope brand.

Matthew Ashton

Date: Tuesday 14th June, 11:11am

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