Allerton Windows

Home Extensions

Create space that suits your lifestyle.

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3 Pane Bifolds included with our extensions for free. Watch your design come to life!

House Extension Builders Liverpool

Expert House Extension Builders in Liverpool

From inspiration to execution, watch your design ideas come to life with a home extension from Allerton Windows.

An extension from Allerton Windows can add real value to your house, not to mention precious space that can be used for a number of purposes.

Whether you’re seeking to expand your current living room, add dining room potential with a kitchen extension in Liverpool, or create an entirely new space for your family to enjoy; Allerton Windows has over 25 years of experience in realising their clients’ plans from design to completion.

Get in touch today to find out more!

Watch your

Designs Come To Life

Our construction experts have years of experience and have built up a stellar reputation for completing jobs on time and within budget. We understand that building an extension is a big investment and aim to make the experience as smooth as possible, from drawing up your plans to tidying up after ourselves on the final day.

Swipe the images to see just how we build this luxury property renovation, including a home extension, two balconies, and an outside kitchen and living area.

Design. Plan. Build. It’s what we do.

Bifold Doors extension in West Derby.

Buy On Finance

3 years interest-free financing is available.

Restrictions apply, credit is subject to status, application, financial circumstances and borrowing history.

Find out more

Stratus Roof Lantern Systems

Feature an elegant Stratus aluminium lantern roof system as the centrepiece of your new living space.

This state-of-the-art roof system is designed to provide excellent thermal performance, whilst maintaining a sleek, stylish finish that won’t detract from the aesthetic appeal of your new living area.

Make your living space a perfect place to relax no matter what the seasons throw at it. Most importantly, these lantern roofs let in masses of light into your new living room, kitchen, or dining area.

Stratus provides a number of design options to choose from which we are happy to walk you through. Roof Lanterns come in either 2-way, 3-way or contemporary designs and can be powder-coated in either Anthracite Grey or Crisp White.






Why choose us to install your House Extension

  • Energy efficient.Thermal insulation above and beyond competing door brands. Keep the cold air out, the warm air in and save money on your energy bills.
  • Security.ERA ‘Five-Star’ security guarantee against forced entry for a period of 10 years. Safety first and foremost.
  • Low maintenance.Just wipe clean with warm water and lubricate tracks once a year. Simple maintenance and no rigorous cleaning regimes.
  • Weather resistant.Triple-sealed to eradicate draughts and ensure excellent weather tightness. A door you can trust, every season.
  • Insulated core.Innovative aluminium construction provides peerless thermal performance. An extra layer to give you peace of mind.
  • Easy access to outdoor spaces. Bifold doors offer the benefits of having multiple windows whilst granting easy access. Sliding bi-fold doors allow light to fill the room, whilst giving you a seamless transition to your garden. Transform how you enjoy both your indoor and outdoor living space.
  • Clear views through to your garden. Bifold doors are the perfect addition to a living space that faces onto a back garden or patio. By installing bifold doors into your home you can unlock the potential of both your indoor and outdoor living spaces.
  • Make the most of your living space. Bifold doors are a step above any run-of-the-mill patio doors, giving you the opportunity to breathe fresh life into your house and how you enjoy your living spaces.
  • Transform how you enjoy your home. The enjoyment of your home can be transformed with these sleek sliding doors, making summer BBQs, al fresco dining and house parties an elegant, simple experience.

What areas in Liverpool do you build and service extensions?

We provide accredited and experienced domestic construction expertise across Merseyside. Below, we’ve listed some of the areas we serve across Liverpool. We offer our extension services to the following areas across the Liverpool region: Kirby, Knowsley, Huyton, Belle Vale, Woolton, Aigburth, Dingle,  Toxteth, Vauxhall, Bootle, Seaforth, Great Crosby Litherland, Aintree, Walton Wavertree, Woolton and more.

Why choose us for your House Extension?

Allerton Windows is Liverpool’s largest local independent home improvement specialist. We’ve put excellence in customer service and aftercare at the heart of our business since starting establishing the business in 1995. Since then we’ve garnered hundreds of positive reviews from happy homeowners and businesses across Merseyside.

We’re a Liverpool business through and through, as such, in the spirit of our great city we consider it our responsibility to treat all our customers fairly from our first meeting to our last.

The reviews speak for themselves.


We chose Allerton Windows for our extension. From Stephen the salesman at the start to Tony the builder and everyone that has worked on it, it's been a 1st class job. Nothing was ever too much trouble, from phone queries to face to face with Tony, everything was professionally done and every trade person we had who has worked on the job have been brilliant. We are over the moon with our new extension it looks amazing, it's a dream come true really. Thanks to everyone at Allerton Windows for making such a big job seem so seemless. I would highly recommend Allerton Windows to anyone and will be doing in the future. Thank you.

In February 2020 we finally decided to go ahead with our long term plans for an extension and new kitchen. The plans in our mind were to completely transform our kitchen, dining and seating are. Then the world was hit by COVID and things were quickly put on hold. I had a few builders and contractors in mind to complete the work when we could. I followed Allerton Windows projects on social media and was impressed with their feedback. As lockdown (1) lifted I asked 4 different companies to give me a quote. 2 failed to recall me, one made an appointment and didn’t arrive, however Paul from Allerton Windows arrived on time and was excellent in talking through my ideas giving guidance. Within 2 days I had a full estimate which was broken down into exact detail of what we would be paying for. On agreement we were only asked to wait four weeks whilst the drawings were submitted before a start date was given. The project was planned for 8 to 10 weeks. We are now complete and despite all that’s going on in the world we are absolutely overwhelmed with the final product, the quality of work. More importantly is to mention that all trades people and the staff at Allerton Windows have been excellent. Everything we imagined has come to fruition. The skill and dedication of all the workers has been without fault. Tony and Paul have always been on hand for advice and nothing seems to have been any trouble. We have had numerous friends and neighbours ask for details of Allerton Windows, where I would normally hesitate in making recommendations for such large projects, I have no problems in pointing anyone to Allerton Windows, they have been fantastic and again especially in such uncertain times. Thanks Robbie and Helen

I have recently just had a total house renovation undertaken by Allerton Windows. After getting many other quotes off other firms, I found Allerton Windows to be very competitive. They covered the whole project from start to finish this included; building work, full re-wire, plumbing, plastering, tiling and garden landscape. I went to their showroom in Bootle and that confirmed my decision. The person I dealt with was very knowledgeable and kept me well informed throughout the renovation, I cannot fault Allerton windows. I would highly recommend them for every aspect of building work.

We have recently had our extension completed by the team at Allerton Windows and we are extremely pleased with the end result. The person I dealt with has been great throughout the whole process - checking on progress and helping us throughout with and questions or queries. All of the workmen involved in completing the extension were professional and friendly and all work was completed to a high standard. We would happily recommend Allerton Windows to anyone based on the service and quality of work we have received.

After having several companies quote for our extension we went with Allerton due to the amount of positive reviews and the person's knowledge and honesty. All the options were explained and there were no hidden costs. We were provided with a start date and they arrived the day before to check there were no access issues. They began work on 05/11/19 and finished on 04/12/19, every day we were informed what would be happening the day after. We were so impressed, all the workers were helpful and answered any questions. I can’t fault them and would highly recommend them. Thank you.

Why Choose Allerton Windows

  • Made to orderMade and measured to your exact project and installed perfectly for you.
  • Expert installation25 years of experience improving homes in the North West.
  • 500+ great reviewsHundreds of five-star reviews from happy customers.
  • Established in 1995Liverpool’s largest local independent specialist.
  • Local BusinessTreating all our customers fairly from our first meeting to our last.


  • How much does a house extension cost in the UK?
  • A house extension can cost between £20,000 and £70,000 + VAT. This range of prices is representative of different styles of extension, for example, your house extension would cost more if you were adding a bathroom or kitchen and a second-storey extension would also push the cost up further.

  • Do I need planning permission for a home extension?
  • You will need planning permissions for a home extension if the size of the extension is more than half of the land around the original house. Or, if your home is being brought nearer to a public highway, or if you plan on building higher than the tallest point of your home. You'll also need planning permission if you're planning on using materials different to those currently used in your home.

  • What is the maximum extension without planning permission?
  • The maximum size extension you can build without planning permission will depend on the size of the land around your original house. When building without planning permission your extension can be no larger than half the area of land around your original house. Single-storey rear extensions must also be no larger than 3 metres if semi-detached or 4 metres if detached.

  • How much does it cost to have a single-storey extension?
  • A single-storey extension can cost between £20,000 and £40,000 + VAT, however, this price could increase depending on the complexity and size of your project. You may pay between £1,200 and £1,500 per square metre for your extension, so a small 3 x 5 metre single-storey extension could cost as little as £18,000 + VAT, depending on the materials used.

  • Is it cheaper to do a loft conversion or an extension?
  • A loft conversion is usually cheaper than an extension. The cost of new foundations and roofing typically make house extensions more time-consuming and expensive than loft conversions, however, in many cases, they add more value and practical use to the homeowner.

  • What is the most expensive part of building an extension?
  • The most expensive parts of building an extension are usually the roofing and the foundation, as building these requires the most manpower and time. Building a two-storey extension can offer better value to those with the funds who are willing to maximise the space in their home.

  • Can I draw my own plans for building regs?
  • You won't be able to draw your own plans for building regs, as these plans should be professionally drawn in order to satisfy the local authority building council if their approval is needed. Hiring an experienced firm to manage your extension build can help you quickly navigate any problems that might arise from seeking planning approval.

  • How do I build my own extension?
  • Building your own extension requires a great deal of planning and time in order to get right. Designing a functional house extension that also looks great is not a simple task, and managing the construction of your extension can also be a job in itself. Assess your own skills, abilities and constraints before deciding to self-build your extension and weigh up the benefits of paying a professional to take on the work for you.

  • What is a house extension?
  • A house extension is a construction project that involves expanding the existing living space of a house. It aims to create additional rooms or enlarge existing ones to accommodate the changing needs of homeowners.

  • What are the benefits of a house extension in Liverpool?
  • House extensions in Liverpool offer several benefits, including increased living space, added functionality, improved property value, the ability to customise the layout, and the opportunity to create a home that meets specific requirements.

  • Can I have a bespoke house extension designed to match the architecture of my Liverpool home?
  • Yes, a bespoke house extension can be designed to complement the existing architecture of your Liverpool home. Skilled architects and builders can work closely with you to create a seamless and harmonious extension that blends with the original design.

  • What types of house extensions are popular in Liverpool?
  • Popular types of house extensions in Liverpool include rear extensions, side return extensions, wrap-around extensions, or even two-story extensions. The type of extension you choose depends on your property's layout, available space, and desired outcome.

  • Do I need planning permission for a house extension in Liverpool?
  • Planning permission requirements for house extensions in Liverpool depend on various factors, such as the size, location, and specific guidelines set by the local authority. It is advisable to consult with professionals or the local planning department to determine if planning permission is needed.

  • How long does it take to complete a house extension in Liverpool?
  • The duration of a house extension project in Liverpool can vary depending on factors such as the size, complexity, weather conditions, and any necessary planning permissions. On average, a house extension can take several months to complete.

  • Can I include energy-efficient features in my house extension in Liverpool?
  • Yes, integrating energy-efficient features into your house extension is highly recommended. This can include energy-efficient windows, insulation, eco-friendly heating systems, and LED lighting to reduce energy consumption and decrease your carbon footprint.

  • Can I convert my loft into a house extension in Liverpool?
  • Converting a loft into a house extension is a popular choice in Liverpool. It can provide valuable additional living space and is often a cost-effective way to expand your home without altering the existing footprint. Loft conversions offer flexibility in design and can be customized to suit your specific needs and preferences.

Allerton Windows

Fill in the form or call us now to get your project started: 0151 268 03860151 268 0386

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    Find Our

    Liverpool Showroom

    From Liverpool City Centre: Simply drive north from the city centre along Great Howard Street (A565), with the Mersey on your left.

    After passing the Shell garage prepare to turn right onto Strand Road (A5057), and then take the third left up Irlam Road.

    After a minute’s drive, you’ll pass a handsome red brick warehouse, and then you’ll see our signage on our blue-painted walls, there’s plenty of parking on site.






    Map showing Liverpool Window Showroom Allerton Windows in Bootle.