Looking to expand your home with a house extension in the North West? At KJL Builders, we specialise in designing and building high-quality home extensions that transform living spaces and increase property value.
With years of experience delivering house extensions across Greater Manchester and the North West, our skilled team manages every stage of the project — from planning and design to construction and completion.
Whether you need a larger kitchen, additional bedrooms, a home office, or a modern open-plan living area, we create extensions that blend seamlessly with your existing property.
Call us today on 07549997985 for a free consultation and quote.​​
Professional House Extension Builders
Choosing the right builder is essential when planning a home extension. At KJL Builders, we provide a complete service designed to make your project smooth and stress-free.
Our team works closely with homeowners in the North West and surrounding areas, delivering extensions that are practical, stylish, and built to last.
Why Choose KJL Builders?
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Experienced house extension specialists
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Fully managed projects from start to finish
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High quality workmanship
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Transparent pricing with no hidden costs
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Local builders serving Altrincham and Greater Manchester
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Tailored designs to suit your home and lifestyle
Our goal is simple: to build beautiful, functional spaces that enhance how you live.
Single Storey House Extensions
A single storey extension is one of the most popular ways to expand your home. Perfect for creating larger kitchens, open-plan living spaces, dining areas, or home offices.
Benefits include:
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Increased ground floor space
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Improved natural light
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Seamless indoor-outdoor living
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Ideal for modern kitchen extensions
Double Storey House Extensions
A double storey extension significantly increases both ground and upper floor space.
This option is ideal if you need:
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Additional bedrooms
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Extra bathrooms
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Larger living areas
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A complete home layout transformation
Double storey extensions provide excellent value because they maximise space while sharing structural costs.
Rear Kitchen Extensions
A rear extension expands the back of your home, creating larger living areas or open-plan kitchens that connect to the garden.
Rear extensions are perfect for homeowners who want to:
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Create open-plan kitchen-dining spaces
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Improve natural light with bi-fold doors
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Extend living areas without reducing front space
Side Return Extensions
A side return extension uses the narrow space beside your property to extend the kitchen or living area.
These are particularly popular with:
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Terraced houses
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Semi-detached homes
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Properties with unused side space
This extension type can dramatically improve layout and functionality.
Wrap Around Extensions
A wrap-around extension combines rear and side extensions to create a large open living space.
This option completely transforms the ground floor and is ideal for:
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Large open-plan kitchens
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Family living areas
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Modern home layouts
How Much Does a House Extension Cost?
One of the most common questions we get is:
“How much does a house extension cost?”
While every project is different, a typical extension in the UK generally ranges between:
£2,500 – £3,000 per square metre
The final price depends on several factors.
Factors That Affect Extension Costs:
Size of the Extension
Larger extensions require more materials, labour, and time, increasing overall costs.
Type of Extension
Single storey extensions usually cost less than double storey or wrap-around extensions.
Materials and Finishes
High-end materials, bespoke features, and premium finishes will increase the total budget.
Design Complexity
Architectural features, structural changes, and complex layouts require additional work and expertise.
Location and Site Conditions
Access, ground conditions, and local regulations can also impact the cost.
Here are some rough examples based on the typical £2,500 – £3,000 per m² range.
Small Single Storey Extension (20m²)
Estimated cost: £50,000 – £60,000
Ideal for kitchen or dining room expansions.
Medium Double Storey Extension (40m²)
Estimated cost: £100,000 – £120,000
Perfect for adding bedrooms and expanding living areas.
Large Wrap Around Extension (60m²)
Estimated cost: £150,000 – £180,000
Great for full ground floor transformations and open-plan living.
For an accurate estimate, we recommend requesting a personalised quote based on your property and design requirements.
At KJL Builders, we follow a clear and structured process to ensure your project runs smoothly from start to finish.
Initial Consultation
We begin by discussing your ideas, goals, and budget. This helps us understand exactly what you want from your extension.
Design and Planning
Our team works with architects and designers to create a layout that complements your home. We also assist with planning permission and building regulations if required.
Detailed Quotation
You’ll receive a clear and transparent breakdown of costs, including materials, labour, and timelines.
Material Selection
We help you choose the best materials and finishes to match your vision and ensure durability.
Construction
Our experienced builders handle every stage of the build, maintaining high standards of workmanship throughout.
Quality Checks
Regular inspections ensure your extension meets our strict quality standards.
Project Completion
Once construction is complete, we walk through the finished project with you to ensure everything meets your expectations.
Aftercare Support
Even after the build is finished, we remain available for any support or advice you may need.​​​
Example House Extension Costs
Our House Extension Process
House Extension FAQ
How much does a house extension cost?
House extensions typically cost between £2,500 and £3,000 per m², depending on size, design, and materials. Contact us for a personalised quote.
Do I need planning permission for a house extension?
Some extensions fall under permitted development, meaning planning permission may not be required. We can advise you and help with the planning process if needed.
How long does a house extension take to build?
A typical single storey extension takes around 8–12 weeks, while larger extensions may take 3–5 months depending on the project.
Will a house extension add value to my home?
Yes, a well-designed extension can increase both living space and property value.
What type of house extension should I choose?
Popular options include single storey, double storey, rear, and wrap-around extensions. The best choice depends on your property and needs.
Do you manage the entire extension project?
Yes, we provide a fully managed service including design, planning support, construction, and completion.