Extension Builder
Cornwall
At BR Construction SW Ltd, we specialise in creating custom home extensions that perfectly blend with your existing space.
Design and build
Ready to Expand Your Living Space?
As trusted extension builders in Cornwall, we specialise in creating high-quality home extensions that suit your unique needs and budget.
Whether you’re looking for a house extension builder to expand your living space or seeking a local home extension builder to add a home office, we have the experience and skills to bring your dream extension to life.
Our team, with expert carpentry and tradesperson services, works with homeowners across Cornwall, including Falmouth, Truro, and St Ives, delivering tailored solutions and exceptional craftsmanship throughout the design and build process.
Some of our happy customers
Tailored solutions for you
Our Home Extension Services
New Build
Extensions
Design your dream space from the ground up with extensions tailored to enhance your newly built home, offering extra room and functionality to suit your lifestyle.
Loft
Conversions
Make the most of your unused loft space, turning it into a beautifully designed living area or convenient storage, perfect for adding that extra room without expanding your home's footprint.
Single Storey
Extensions
Effortlessly expand your home with a stylish and seamless single-storey addition, perfect for creating new kitchens, living rooms, or versatile spaces for everyday living.
Kitchen
Extensions
Transform your cooking and dining experience by creating a sleek, modern kitchen-diner, ideal for hosting family gatherings, dinner parties, or simply enjoying meals together.
Garage
Conversions
Unlock the full potential of your garage by converting it into a functional living space, whether for a home office, extra bedroom, playroom or even an area for hosting friends and family.
Double Storey
Extensions
Maximise your home’s potential by adding an entire extra floor, providing the perfect solution for additional bedrooms, bathrooms, or a spacious home office.
Bathroom
Extensions
Enhance your home with a stylish and functional bathroom extension, creating a luxurious retreat for relaxation and convenience. Whether you’re looking to add a spa-like sanctuary or a en-suite.
Wrap Around
Extensions
Maximise your space with a wrap-around extension. This versatile addition enhances both function and space, creating an area perfect for a kitchen, family room, or dining space.
PREVIOUS PROJECTS
Extension Project Gallery
No need for an architect
Design and Build
Explore our portfolio to see why we’re one of the top-rated construction companies in Cornwall. Each project reflects our dedication to high-quality craftsmanship, attention to detail, and client satisfaction.
Trevascus Farm - after and before
Edgecombe Terrace - after and before
Extension Builder in Cornwall
Looking For The Best Extension Builders Near You?
Why Choose BR Constructions SW Ltd?
We’re Cornwall's
Trusted Extension Builder
Established
in 2018
Competitive
Pricing
Sustainable
Practices
LABC Award
Finalist
Frequently Asked Questions
What is the 50% rule for house extensions?
The 50% rule states that your house extension must not exceed 50% of the total land around the original house. This applies under permitted development rules, meaning extensions must comply with size restrictions without requiring planning permission. Consulting an experienced extension builder ensures your project follows regulations.
What is the cheapest way to extend a house?
The most cost-effective house extension methods include single-storey extensions, garage conversions, and loft conversions. Using timber frames, keeping the design simple, and working with expert tradespeople to streamline the construction process can also help reduce costs.
How much is the average house extension in the UK?
The cost of a house extension varies based on size, materials, and complexity. On average:
• Single-storey extension: £1,200 – £1,800 per m²
• Double-storey extension: £1,500 – £2,500 per m²
• Garage conversion: £10,000 – £30,000
For a bespoke quote, Give us a call on 07843482366
What size extension can I build without planning permission in 2025?
Under permitted development rules, you can typically build:
• Single-storey rear extensions: Up to 4m for detached houses, 3m for others.
• Double-storey extensions: Up to 3m deep.
• Loft conversions: Up to 40m³ (terraced houses) or 50m³ (detached/semi-detached).
Can my neighbour stop me from building an extension?
Neighbours cannot stop your home extension if it follows planning regulations. However, under the Party Wall Act, they must be informed if work affects shared walls or boundaries. Resolving concerns through project management can prevent disputes.
What does it cost for a house extension?
The cost of building work depends on the extension type, materials, and location. A standard home extension typically costs between £30,000 and £100,000. We offer tailored solutions for new builds, renovations, and extensions to suit your budget.
Latest Blogs...
How to Find the Best Builders in Cornwall
Throughout the years, we’ve been trusted to deliver exceptional building services across Cornwall, blending craftsmanship with modern expertise. We specialise in house and commercial developments from cottage developments to large-scale
Top Considerations for Building a New Home in Cornwall
Have you ever wondered what separates a quality home build from an average one? Whether you’re planning a modern eco-build or restoring a listed property, the right expertise makes all
The Types Of House Extensions In Cornwall: Designs & Ideas
Did you know that over 60% of homeowners in Cornwall prefer extending their homes over moving? Our construction company excels in enhancing living spaces across this stunning region. We offer
How Do I Find A Builder For An Extension In Cornwall?
As experienced builders of extensions in Cornwall, we understand only too well the joy and agony of the home renovation experience. The right builder can make your dream a reality,
A Step-by-Step Guide to Working with a Construction Company!
Ever wondered how to turn your construction dreams into reality without getting bogged down in project complexities? Well, our detailed guide will clear up the mystery of working with a
What Does a Construction Company Do? A Complete Guide to Building & Renovation Services
In Cornwall, construction projects can significantly boost a property’s value by up to 25%. Our construction company excels in bringing architectural dreams to life across the Cornish landscape. \ BR
Extension Builder Bodmin | Extension Builder Camborne | Extension Builder Falmouth | Extension Builder Fowey | Extension Builder Launceston | Extension Builder Looe | Extension Builder Newquay | Extension Builder Padstow | Extension Builder Penryn | Extension Builder Redruth | Extension Builder Saltash | Extension Builder St Austell | Extension Builder St Ives | Extension Builder Truro | Extension Builder Wadebridge