7 Types of House Extensions: The Ultimate Guide

Deciding to extend your home can be an exciting yet daunting process.

With so many options available, how do you determine which type of extension is right for your property and lifestyle needs? 

Moreover, this guide simplifies the most popular types of house extensions in the UK, outlining the key features, pros, and cons, and costs linked with each.

Learn about picking the right extension for your home improvement project.

A List of 7 Types of House Extensions

Available in the UK

  • Loft Conversion

    It is one of the most popular ways to add living space to your home in London. Additionally, loft conversions in London involve converting your previously unused loft area into a functional living space such as a bedroom, office, playroom, or bathroom.

    Key Features:

    1.  Utilises wasted attic space
    2.  Can add significant value to your home
    3.  Minimal disruption to existing rooms downstairs
    4.  Variety of layout options – open plan or separate rooms


    1.  Relatively quick and easy to complete
    2.  One of the most cost-effective extensions
    3.  Doesn’t take up outdoor space
    4.  Little planning permission required
    5.  Can make good use of awkward roof spaces


    1.  Limited head height in parts of the room
    2.  Access only via staircase – not ideal for elderly/disabled
    3.  Roof insulation will need improving
    4.  Can make the upstairs colder by exposing the roof

    Cost:  On average, expect to pay £20,000 – £40,000 for a basic loft conversion. Furthermore, complex projects with dormer windows or structural work may cost up to £70,000.

  • Basement Extension

    Digging down to increase your living space can be an efficient way to add extra room if you have limited outdoor space. In fact, basement extensions, which are among the various types of house extensions, are ideal for those in the city where land is scarce.

    Key Features:

    1.  Creates space under the house in the foundations
    2.  Ideal for adding bedrooms, bathrooms, and playrooms
    3.  Minimal impact on existing rooms above ground


    1.  Doesn’t alter the external appearance of the house
    2.  Provides secluded, quiet rooms
    3.  Can significantly increase property value
    4.  Opportunity to install large windows and let in light


    1.  Disruption during the dig down, which can take months
    2.  Damp and flooding risks need to be prevented
    3.  More complex construction and regulations
    4.  Access only via stairs – not ideal for some

    Cost:  Due to the significant excavation work, you can anticipate paying £50,000 – £100,000+ for a basement extension.

    Side Return Extension

    A side return, sometimes called a side annexe, extends your house sideways to fill space alongside the main walls. Not only does this discreet extension maximize space, but it’s also a good option for Victorian terraced or semi-detached homes.

    Key Features:

    1.  Built projecting out from the side wall
    2.  Ideal for widening kitchens or bathrooms
    3.  Single or double-storey options


    1.  Creates an illusion of widened floorspace
    2.  Doesn’t affect existing rooms
    3.  Provides natural light into the middle of the house
    4.  Minimal impact on neighbours


    1.  Smaller in size than a rear extension
    2.  Constructing the adjoining wall can be tricky
    3.  Careful matching of bricks and style needed

    Cost:  On average, a single-storey side return costs £25,000 – £35,000. Additionally, the double storey can cost up to £100,000.

  • Rear Extension

    Extending outwards from the back of the house is a straightforward way to gain extra floor space. Moreover, the classic rectangular rear extension can accommodate larger kitchens, dining areas, and ground-floor bathrooms.

    Key Features:

    1.  Projects out from the back of the property
    2.  Ideal for expanding kitchens, family rooms and entertaining spaces
    3.  Various widths, lengths and heights


    1.  Provides the most useable floor area
    2.  Straightforward construction process
    3.  Opportunity for big bifold doors and open views
    4.  Can be built over multiple floors


    1.  Impacts the outdoor area more significantly
    2.  Getting planning permission can be difficult
    3.  Avoiding overlooking neighbours’ homes
    4.  Matching existing style and brickwork

    Cost:  Expect to pay £25,000 – £100,000+ depending on size. Furthermore, double-storey rear extensions cost more.

    Two Storey Extension

    Consider opting for different types of house extensions by building up and out with a double storey side extension for maximum extra space. Notably, this adds entire rooms both downstairs and upstairs.

    Key Features:

    1.  Ground floor rooms built off existing downstairs
    2.  Extra bedrooms and bathrooms added upstairs
    3.  Pitched roof matching house height


    1.  Significantly increases floor area and value
    2.  Opportunity to remodel layout entirely
    3.  Feels like part of the original house


    1.  Much higher budget required
    2.  Complex construction and regulations
    3.  Getting planning permission is harder
    4.  Major impact on garden space

    Cost:  Due to the size and scale, two-storey extensions typically cost £100,000 – £250,000.

  • Conservatory

    A glass garden room extension that allows light to flood into your home. Furthermore, conservatories provide a versatile additional living space.

    Key Features:

    1.  Largely glazed walls and roof panels
    2.  Typically, uPVC or aluminium frames
    3.  Independent wood or concrete base


    1.  Light, airy, spacious feel
    2.  Bring the outdoors inside
    3.  Quick and easy to install
    4.  Affordable way to gain extra space


    1.  Can become extremely hot in summer
    2.  Typically less insulation than the main house
    3.  Cheaper finishes than a brick extension
    4.  Needs cleaning and maintenance

    Cost:  Expect conservatory costs to range from £5,000 – £20,000 depending on size and materials.


    A style from the array of types of house extensions, orangeries combine brick pillars and glazed panels. Additionally, they provide an airy space that can be used all year round.

    Key Features:

    1.  Brick columns combined with glass roof panels
    2.  Typically has a lantern roof structure
    3.  Doors leading out to the garden


    1.  Benefits from ample natural light
    2.  Not as hot as a conservatory in summer
    3.  Quieter in bad weather than a conservatory
    4.  A versatile room for entertaining


    1.  More expensive than a conservatory
    2.  Not as warm and cosy as a brick extension in winter
    3.  Still prone to some temperature extremes

    Cost:  Due to their bespoke design, orangeries cost between £25,000 – £50,000 depending on size.

  • Choosing the Right Extension for Your Home

    When deciding which type of extension is best for your property, here are some essential factors to consider:

    Budget – What is your budget limit? Some extensions are more cost-effective than others.
    Space available – Can you extend sideways, rearwards or upwards? Measure your outdoor area.
    Planning regulations – Will local policies allow the size and type of extension you want?
    Usage – How will you use the new space? Select an extension suited to your needs.
    Disruption – All extensions will cause disruption, but some build longer.
    Aesthetics – Choose a design that complements your existing home’s style and structure.
    Timescale – Some extensions can be completed in weeks, while others may take several months.

    Extension Planning Permission and Regulations

    Most types of house extensions in the UK require planning permission from your local council. However, there are exceptions if the extension is small or single-storey on detached homes. Building regulations approval is also needed to ensure structural integrity and fire safety.
    When planning an extension, valuable resources include:

    London Extensions – For all your extension needs in London
    Planning Portal – Check if your project requires permission
    Architectural Designer – Ensure regulations compliance and quality design
    Structural Engineer – Assess the feasibility and safety of the proposed extension
    House Extension Builders – Obtain accurate quotes comparing construction costs
    Party Wall Agreement – Sort out legal requirements

    When planning an extension, valuable resources include:
    Factor in additional time and costs if your extension requires permission. Planning officers will evaluate:

    1.  Local development rules and restrictions
    2.  Visual impact on the street and neighbours
    3.  Effects on natural light in adjoining properties
    4.  Sufficient parking provision after the extension

  • Financing Your Extension Project

    Adding extra living space is a significant investment to enhance your lifestyle and boost your property value. There are several routes to financing your extension:

    House remortgage – borrow extra based on increased property value
    Secured loan – use your home as collateral
    Personal loan – unsecured borrowing based on credit rating
    Savings – self-funding is less risky if funds allow
    Inheritance – cash gifts can fund part or all of the project

    Compare repayment terms and interest rates before choosing a loan. Moreover, using a qualified financial advisor can help identify the proper financing option for your needs and budget.

    Maximising Value By Designing a Functional Extension

    Careful planning is needed to ensure your extension, among the various types of house extensions, offers maximum usable floorspace and value for money spent:

    1.  Choose multipurpose rooms suited to both living and entertaining
    2.  Optimise natural light with skylights, glass doors and large windows
    3.  Incorporate energy-efficient insulation, heating and appliances
    4.  Landscape the garden to complement the new extension
    5.  Add Porcelain tiled flooring for a sleek, spacious look and feel
    6.  Install dimmable spotlights on a smart lighting system
    7.  Build storage solutions into the extension design
    8.  Ensure seamless flow between old and new rooms

    This checklist will help boost your return on investment and create a stylish, functional living space your family can enjoy for years.

Choosing Experienced Builders

for Your Extension

As a major home improvement project, your extension deserves to be constructed to exceptional standards by specialist tradespeople. Here’s what to look for when hiring builders:

1.  Extensive experience constructing house extensions similar to yours
2.  Photographs and testimonials from satisfied previous clients
3.  Fully certified electricians, plumbers, roofers and structural workers
4.  A portfolio showcasing high-quality craftsmanship
5.  Detailed quotations outlining precisely what is/isn’t included
6.  Availability to start your project within your preferred timeframe
7.  Strong communication skills and transparency throughout the build
8.  A willingness to get building regulations approval for the works

If you choose extension builders with proven expertise, you can feel reassured your project will be completed to the highest quality standards. Superior quality also reduces the risk of problems arising down the line.

Types of House Extensions

Investing in a home extension is a significant decision that requires careful planning and research to determine the best type, size, design, and building team for your needs.

This guide covers the key considerations and steps to expand your living space successfully. With innovative design and skilled construction, your extension can enhance the look and functionality of your home for many years to come.

Get in Touch with London Extensions

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