Barnet has some of the most tightly controlled streets in London and some of the most open, often a few miles apart. Hampstead Garden Suburb, Totteridge, Mill Hill and Monken Hadley are conservation areas, while large parts of Finchley, Whetstone and New Barnet are Edwardian and interwar streets where extending a house is more straightforward.
London Building Contractors
Builders in Barnet Built on Craftsmanship and Clear Communication
What We Do
Building Services from Barnet Builders
Every service below is delivered by our own in-house tradespeople, fixed-price and fully insured, so you get dependable builders in Barnet from survey to handover.
Loft Conversions in Barnet
Transform your home with expert loft conversions in London by Alpha London Builders. From design and planning to construction, we deliver quality loft conversions tailored to your needs.
Learn more →House Extensions in Barnet
Rear, side return, wraparound and double storey extensions designed and built to fit seamlessly with your London home.
Learn more →Basement Conversions in Barnet
Cellar conversions, basement lowering and full new excavations, engineered and waterproofed to BS 8102 by our in-house team.
Learn more →Garage Conversions in Barnet
Integral, attached and detached garage conversions into bedrooms, offices and annexes, most without planning permission.
Learn more →Property Refurbishment in Barnet
Cosmetic updates through to full structural refurbishments, managed under one dedicated site manager from start to finish.
Learn more →General Building in Barnet
Repointing, roof repairs, damp treatment, brickwork and small structural alterations, carried out by our own trades.
Learn more →Design & Build in Barnet
One team, one contract, one fixed price for design, planning, structural engineering and construction on your project.
Learn more →New Builds in Barnet
New homes and replacement dwellings built from foundation to final finish, with zero-rated VAT on construction costs.
Learn more →Commercial Building in Barnet
Office, retail and restaurant fit-outs across London, delivered around your trading hours with minimal disruption.
Learn more →Residential Building in Barnet
The full range of residential building work, from a single repair to a new build, delivered by one London contractor.
Learn more →Building Demolition in Barnet
Safe, fully licensed demolition work across London, from internal wall removal to complete house demolition ahead of a new build.
Learn more →Why Choose Us
Why Choose Our Barnet Builders
A plan for Hampstead Garden Suburb
The Trust's Scheme of Management runs alongside planning, so we build its approval into the programme from day one.
Green Belt sizing done properly
Around Totteridge and Monken Hadley we measure against the original house first, because that is how Green Belt policy judges an extension.
Edwardian and interwar houses
Finchley, Whetstone and New Barnet have the roof shapes and plot sizes that suit dormer lofts and rear extensions, and we price them from a proper survey.
Fixed price, itemised
Every quote is itemised and fixed after a survey, so the figure agreed for your Barnet project is the figure you pay.
Local Knowledge
Building & Planning Considerations in Barnet
Barnet's conservation areas include Hampstead Garden Suburb, Mill Hill, Monken Hadley, Totteridge and Finchley Church End, and the council has used Article 4 directions in parts of the borough to remove permitted development rights. Hampstead Garden Suburb adds a second layer: the Hampstead Garden Suburb Trust runs a Scheme of Management, so many external changes need the Trust's consent as well as the council's. Around Totteridge and Monken Hadley, Green Belt policy also limits how far a house can be enlarged. Elsewhere in the borough, most houses keep their standard permitted development rights for rear extensions and rear dormers.
As Barnet builders, every quote we provide for a Barnet property starts with a check against Barnet Council's conservation area maps and Article 4 register, so you know exactly which route your project needs before any design work begins.
Local Guide
Building in Barnet: what to know before you start
A borough of very different streets
Finchley and East Finchley have plenty of Edwardian and interwar semis and terraces. Whetstone, Mill Hill and Edgware lean towards 1930s semis, and the biggest houses are around Totteridge and Monken Hadley. High Barnet and New Barnet add Victorian terraces and villas near the stations. The Arts and Crafts houses of Hampstead Garden Suburb are a category of their own, because the roofs, brickwork and windows are part of why the area is protected.
What tends to work where
On the 1930s semis, loft conversions in Barnet usually mean a hip-to-gable and a rear dormer. On Edwardian houses in Finchley, extensions tend to be rear and side-return. The large detached houses towards Totteridge are where full refurbishment or a basement can make sense, but Green Belt rules mean the starting point is the size of the original house, not the size of the plot.
Before you commission drawings
If you are in Hampstead Garden Suburb, approach the Trust early: its approval runs alongside the council's and can set the pace of the whole job. If you are in the Green Belt, the question is how large the extension is compared with the original house, so we measure that first. Anywhere in Barnet we check for Article 4 coverage and for neighbours' rights under the Party Wall etc. Act 1996 before anything is drawn.
What we do in Barnet: Loft conversions in Barnet · House extensions in Barnet · Basement conversions in Barnet · Garage conversions in Barnet · Property refurbishment in Barnet
Worth reading first: Building Regulations vs planning permission · How to choose the right builder
Nearby: Builders in Harrow
Ready to talk? Book a free site survey and we will tell you in writing which planning route your address needs.
Areas We Cover
Areas We Cover in Barnet
Finchley
Mill Hill
High Barnet
Hampstead Garden Suburb
Whetstone
Edgware
Totteridge
New Barnet
Don't see your street listed? Our builders in Barnet cover the whole borough and the surrounding area — get in touch to check.
Our Work
Recent Barnet Projects
A look at recent work carried out for clients in and around Barnet.
Full House Rewire & Consumer Unit Upgrade
A complete rewire and 18th Edition consumer unit upgrade for a London flat, tested, certified, and signed off with a full Electrical Installation Certificate.
View Project →
Family Bathroom Renovation
A dated bathroom stripped back and rebuilt with full tanking, marble-effect tiling, underfloor heating, and a walk-in shower enclosure.
View Project →What Clients Say
Reviews from Barnet
“Alpha converted our loft into two bedrooms and a bathroom without a single hiccup. They turned up when they said they would, kept the site tidy, and the finish is better than we hoped for.
”
Priya Shah
Loft Conversion, Walthamstow
Common Questions
FAQs About Builders in Barnet
Is it harder to extend a house in Hampstead Garden Suburb?
Yes. The area is a conservation area with its own design controls, and the Hampstead Garden Suburb Trust runs a Scheme of Management, so most external changes need the Trust's consent as well as planning permission where that applies. We check both before designing anything.
Can I extend a house near Totteridge or Monken Hadley?
Often, but not without care. Green Belt policy restricts disproportionate additions to the original dwelling, so what counts is the size of the house as first built, including any earlier extensions. A well-judged scheme is often approved, but it needs a stronger planning case than the same job in Whetstone.
Do I need planning permission for a loft conversion on an interwar semi in Whetstone or Mill Hill?
Not usually outside conservation and Article 4 areas, as long as the added volume stays under 50 cubic metres for a semi-detached house and the dormer sits on the rear roof slope. Mill Hill has its own conservation area, so check that first. Building Regulations approval is required either way.
How long do approvals take in Barnet?
A householder planning application has an eight-week target at the council, and longer if it goes to committee. Hampstead Garden Suburb Trust consent runs separately, and a Building Regulations application can run alongside the planning one. We give you a realistic timeline in the quote.
Ready When You Are
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