About The Extension Company
Professional house extension specialists serving London and the surrounding counties. 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. What started as a small team of passionate architects and engineers has grown into one of London's leading house extension specialists.
We've completed projects across London, Essex, Kent, Surrey, Hertfordshire, and Buckinghamshire — each one a testament to our commitment to quality craftsmanship, transparent communication, and client satisfaction.
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, Enfield and the Hertfordshire border.
That matters for one simple reason: the projects in our gallery are Pine Grove builds, and yours would be too. When you enquire here, your details go straight to the team who will actually design, manage and build your extension — the same surveyors, the same project managers, the same craftsmen. Nothing is passed on, sold on, or subcontracted to strangers.
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 serve London and the surrounding counties with professional house extension services.
Covering North & South London — Enfield, Barnet, Southgate, Cockfosters & south of the river. 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 across North & South London
Our Services
Expert Team Available
Call now to speak with our expert team. Get instant responses and professional guidance for your extension project.