House Extension Builders London
As one of the leading house extension builders London homeowners trust, KT5 Construction delivers cost-effective and high-quality solutions to help you expand and transform your living space. With expert planning, transparent pricing, and smart cost-saving strategies, we make it possible to achieve your dream home without unnecessary stress or overspending.
At KT5, communication is at the heart of everything we do. We keep you informed every step of the way so your vision always stays on track.
What We Do
Building Construction
New Builds, Extensions, Conversions, Renovations
General Building
Property Maintenance, Handyman Service, Decorating
Design
Planning, Design, Project Management, Quality Checking
House Extension Builders in London You Can Rely On
When you choose KT5 as your house extension builders in London, you benefit from local expertise, reliable delivery, and a customer-focused approach.
Proven Track Record Across London Boroughs
From Richmond to Wandsworth, we have successfully delivered a wide range of extension projects including:
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Single-storey rear extensions
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Wrap-around kitchen extensions
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Double-storey builds
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Loft conversions and dormers
Our specialist team understands the challenges of London builds—from strict planning regulations to maximising every square metre in dense urban areas. Every project is carefully managed to ensure compliance, value, and quality.
Why Choose KT5 Construction for Your Extension
Choosing KT5 Construction means choosing a builder who puts value first. We offer:
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Value engineering to stretch your budget without compromising quality
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Fixed-price contracts for peace of mind and cost certainty
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Detailed programmes and regular updates so you can plan with confidence
We don’t just build extensions—we guide you through the process, helping you save time, avoid common mistakes, and protect your investment.
Client Testimonials
“You made it so simple” – Just wanted to say thank you for making what I thought would be a difficult process much easier than I had imagined.
Thank you for my brand new house! The refurbishment and attention to detail makes it feel like a brand new house, but without the expensive cost of moving.
Just wanted to thank you for the work carried out to my new bathroom, I will definitely be in touch shortly to talk about my proposed kitchen extension.
The Extension Process Step by Step
Initial Consultation and Free Design Offer
We start with a home visit or video consultation to understand your goals. When you choose KT5, we provide free architectural or structural designs to help you save from day one.
Planning and Permission
Our in-house team handles permitted development checks and full planning applications. With London’s complex borough requirements, having local experts makes approvals faster and smoother.
Construction and Project Management
From groundwork to the final finishes, our site managers oversee every stage, ensuring your extension is built to the highest standards.
Why London Homeowners Trust KT5
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Local experience across Kingston, Wandsworth, and Ealing
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Transparent pricing with no hidden extras
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Trusted by homeowners looking for smart, long-term investments
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Rated for punctuality, customer service, and attention to detail
Contact Us Today
Looking for reliable house extension builders London who understand your budget and your area? Contact Us today and discover how KT5 can save you time, money, and stress while building the home you’ve always wanted.
Book your free consultation and take the first step toward creating your dream extension.
Frequently Asked Questions
How much does a house extension in London cost?
Costs vary by size, design, and location. As a guide:
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£1,800–£2,500 per m² for standard builds
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£2,800+ per m² for high-spec finishes
At KT5, we provide fixed pricing and can also phase works in line with your budget.
Do I need planning permission for a house extension in London?
It depends—some extensions fall under permitted development. We’ll advise and handle all applications where required.
How long does a house extension take?
Most extensions take 10–16 weeks, depending on scope and weather conditions. We provide clear programmes so you can plan ahead.
Our Services
House Extensions
KT5 Construction provides professional house or Property Renovations Services in Ash, tailored to your unique needs. Whether you’re expanding your kitchen or creating an open-plan living area, we deliver high-quality results.
Kitchen Refurbishment
At KT5 Construction, we are specialists in kitchen refurbishment in Surrey and surrounding areas, delivering bespoke designs that enhance your living space and add value to your home.
Loft Conversions
At KT5 Construction, we specialise in creating stunning loft conversions in Surrey that add space, value, and style to your home. From dormer loft conversions to luxury loft designs, our expert team handles every detail with professionalism and precision.
Groundworks
At KT5 Construction, we pride ourselves on being the go-to groundwork Company in London, delivering top-quality services for residential and commercial projects.
Bathroom Design & Installation
Your bathroom should be more than just functional—it should reflect your personal style and offer a space to unwind. At KT5 Construction, we specialise in Surrey bathroom design and installation, delivering tailored solutions that blend elegance, practicality, and luxury.
Property Refurbishment
Our Ewell Road Surbiton Project showcases the full spectrum of our refurbishment expertise. By managing every detail, from architectural consultation to final finishes, KT5 ensures each element meets the highest standards.
New Build Homes
As a trusted New Build Builder in Surrey, KT5 Construction has been at the forefront of creating bespoke, high-quality homes designed to meet modern living standards.
Architecture & Design
Expert architectural planning & creative design solutions for residential and commercial projects in Surrey & London.
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