About The Extension Company
House extension specialists for North London, and across the rest of London. We design, plan, and build extensions that transform homes.
Our Story
The Extension Company was founded on a simple vision: to provide professional, reliable house extension services that transform homes and exceed expectations.
Our focus is North London: Enfield, Barnet and Haringey, with Camden and Hackney at the edges. We take on projects across the rest of London too.
Our team includes experienced architects, structural engineers, project managers, and design specialists, all united by a shared passion for creating beautiful, functional spaces that enhance homes and lifestyles.
Today, we offer 12 specialist services covering everything from single-storey extensions and loft conversions to full house refurbishments and structural alterations. Whatever your project, we have the expertise to deliver.
The company behind the brand
Built by Pine Grove Design & Build Ltd
The Extension Company is the dedicated extensions studio of Pine Grove Design & Build Ltd — a registered North London design-and-build company whose team has spent more than 25 years on site across Barnet and Enfield.
That matters for one simple reason: the projects in our gallery are Pine Grove builds. If your home is in North London, yours will be too: designed, managed and built by Pine Grove's own team — the same surveyors, the same project managers, the same craftsmen.
Pine Grove Design & Build Ltd is registered in England & Wales, company no. 13133967.
What We Do
From initial design through to completion, we handle every aspect of your extension project.
Design & Architecture
Our architects create detailed plans, 3D visuals, and construction drawings tailored to your home and how you want to live in it.
Planning & Approvals
We prepare and submit planning applications, liaise with local authorities, and handle building regulations — taking the stress out of the process.
Build & Project Management
Our vetted builders bring designs to life. We oversee construction, conduct site visits, and manage quality at every stage until handover.
Why Work With Us
Expert Team
Qualified architects, structural engineers, and project managers with decades of combined experience across London.
Transparent Pricing
No hidden costs or surprises. We provide clear, upfront pricing with payment structured in stages so you always know where you stand.
Local Knowledge
Deep understanding of London boroughs, planning policies, conservation areas, and what local authorities look for in applications.
End-to-End Service
From the first consultation to final sign-off, we manage everything — design, planning, building regs, construction, and snagging.
Where We Work
We work across London, with the North London boroughs as our focus.
Across London, with a focus on the north: Enfield, Barnet, Southgate, Cockfosters and Muswell Hill. View all locations
Ready to Discuss Your Project?
Contact our expert team for a free consultation and site visit. We'll assess your property and give you honest guidance on costs, timelines, and what's possible.
Get In Touch
Explore More House Extension Services
Discover our comprehensive range of house extension solutions for North London and across the capital
Quick Access
Our Services
North London areas
North London loft conversions
Expert Team Available
Speak to the team about your extension, the planning route or a rough budget. Lines open every day, 9am to 8pm.