House Extension in Friern Barnet
For a House Extension in Friern Barnet, KT5 Construction delivers smart, cost-effective space solutions. From concept to handover, we combine thoughtful design, rigorous planning, and transparent pricing to create the extra room you need—without stress or overspend.
Communication is central to our process: expect regular updates, honest advice, and a tidy, well-managed site throughout. Discover how we build better extensions at KT5 Construction.
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 in Friern Barnet: What to Expect from Local Specialists
Why Choose KT5 for Your Friern Barnet Project
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Local insight, tailored design – We understand Friern Barnet’s mix of Edwardian/Victorian terraces, 1930s semis, and post-war homes, so we design to maximise space while respecting the character of your street.
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Single accountable team – One coordinated partner for design, permissions, build, and finishing—simplifying every decision.
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Fixed pricing, clear programme – Transparent scope, agreed timelines, and regular progress updates—no surprises.
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Value engineering as standard – Smart specifications that stretch your budget without compromising safety, quality, or longevity.
Extensions We Deliver in Friern Barnet & Nearby (North Finchley, Whetstone, New Southgate)
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Single-storey rear kitchen-diner extensions for open-plan family living
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Side-return and wrap-around layouts to unlock underused space
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Double-storey additions for extra bedrooms, bathrooms, or a principal suite
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Loft conversions and dormers to make the most of your roof space
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Garden rooms/orangeries for flexible office, studio, or leisure space
Every project is planned around buildability, compliance, and neat delivery on established residential streets.
Our Value-First Approach
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Budget clarity – Fixed-price contracts and staged payments
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Smart specification – Recommendations balancing aesthetics, performance, and lifecycle costs
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Straightforward comms – Detailed programmes, site updates, and a single point of contact
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Built for the long term – Robust detailing and careful finishing for durability and comfort
How Your Extension Comes Together
Initial Consultation & Free Design Offer
We begin with a home or video visit to understand your goals, budget, and timeline. Choose KT5 as your builder and we’ll include free architectural/structural design to move your scheme forward from day one.
Planning & Permissions
We handle permitted development checks, full planning applications with Barnet Council, party wall coordination where required, and building control approvals—streamlining paperwork so you don’t have to.
Construction & Project Management
Your dedicated site manager schedules trades, inspections, and quality checks—from groundwork and structure to electrics, plumbing, and finishes—delivering a tidy site and a high-quality finish.
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.
Why Friern Barnet Homeowners Choose KT5 Construction
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Local experience across Friern Barnet and wider North London
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No-surprise pricing with clear payment schedules
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Rated for punctuality, service, and attention to detail
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Practical, long-term solutions that genuinely add value
Let’s Create Space That Works
Ready to plan a House Extension in Friern Barnet that’s on time and on budget? KT5 Construction is here to help. Book your free consultation to discover how we can save you time, money, and stress—while building the home you’ve imagined.
Frequently Asked Questions
How much does a Friern Barnet house extension cost?
Costs vary by size, design, and specification. 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
We provide fixed pricing and can phase works to suit your budget.
Do I need planning permission for an extension in Friern Barnet?
Many single-storey rear extensions fall under permitted development (subject to limits on height, depth, and materials). Larger or double-storey schemes usually require planning permission from Barnet Council. We’ll confirm your route and manage all submissions.
How long does an extension take?
A typical single-storey rear extension takes 10–16 weeks from site start, depending on scope and specification. Double-storey or complex structural alterations may take longer. We’ll provide a clear programme before work begins.
Will I need a party wall agreement?
If your home adjoins a neighbour (common with terraces and semis), works such as lofts, side returns, or foundations near the boundary may require Party Wall notices/agreements. We’ll advise and coordinate as needed.
What’s the best way to control costs?
Agree the scope early, keep structural changes efficient, choose durable mid-range finishes, and avoid late variations. Our value-engineering review helps you spend where it truly matters.
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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