Premium Designer Garden Rooms & Annexes
In London, home counties and across the UK
Design Your Room in 5 Minutes
120+Successfully Completed Projects
75+5 Star Google Reviews
100+Satisfied Customers
Faster On-site Installations
- Two week installation guaranteed
- Minimal fuss and disruption to your home
Fully Turn-key Solutions
- From design and planning to manufacture and complete installation
Truly Bespoke and Customisable Design
- Every room is designed around your space, your lifestyle, and your exact requirements
In-house Expertise
- We don’t rely on external contractors
- Our team of experts cover every stage including foundations and electrics
Premium Specification as Standard
- Unlike many providers, key features come as standard
- Including: plastered interiors, flooring, lighting, and climate control options
Built for Year-Round Living
- Fully insulated with high-performing Structural Insulated Panels (SIPs)
- Maintaining warmth in winter and comfort in summer
- Sustainable, energy-efficient: Good for you, Good for the planet
Free 3D Design Configurator
Design and price your room in 5 minutes
1) Choose the style you like
2) Set the size and specs you want
3) Get an immediate price and 3D design
4) Save your design(s) and come back any time
Need help designing?
Garden Annexes
Add high-quality independent living space with a fully equipped garden annexe — ideal for multi-generational living or guest accommodation.
Perfect for:
- Family accommodation
- Guest suites
- Rental opportunities
- Independent living spaces
The Pecasa Build Standard
Every Pecasa building is engineered for durability, efficiency, and long-term performance.
Our premium build includes:
- Structural Insulated Panels (SIPs) construction
- Ground screw foundation system
- High-performance EPDM roofing
- Fully plastered internal finish
- Integrated lighting and electrics
- Quality flooring included
- Climate control options
- Modern doors and glazing
Result: A garden building that performs like a true extension of your home.
Our Simple 4-Step Process
1. Free Consultation & Survey
We assess your space and understand your requirements.
2. Free 3D Design
Visualise your bespoke garden room before build begins.
3. Precision Manufacturing
Your building is manufactured locally to exact specifications.
4. Fast Professional Installation
Most projects completed in as little as two weeks.
Where We Work
Pecasa proudly serves homeowners across:
- London
- Greater London
- Watford
- Hertfordshire
- Surrounding UK regions
If you’re unsure whether we cover your area, our team is happy to help.
Why Invest in a Garden Room?
A professionally built garden room or annexe can:
- Add usable living space without moving house
- Increase property appeal and potential value
- Create separation between work and home life
- Support multi-generational living
- Provide year-round flexible space
With Pecasa’s premium build standards, your investment is designed to perform for decades.
Locally Manufactured. Expertly Installed. Built to Last.
At Pecasa, we combine modern construction technology with expert craftsmanship to create exceptional outdoor spaces through innovative garden rooms design. As a trusted garden room company, we build high-quality garden buildings that go beyond standard market expectations. With a strong focus on structural durability, outstanding thermal performance, and clear, transparent specifications, we ensure every garden room delivers lasting comfort, functionality, and excellent long-term value for homeowners.
Ready to Transform Your Garden Space?
Book your free survey and 3D design today and discover how Pecasa can create a bespoke garden room or annexe tailored to your home.
Need help designing your perfect garden room?
Send us details of your project to book your Free Design Consultation
Two Week Installation
Sustainability
High Quality British Manufactured
Fully Customisable
Our Team
Patrick
Surveyor & Garden Room Expert
Patrick is Pecasa’s professional surveyor and garden room specialist. He has extensive experience in surveying, design, and construction of premium garden rooms, ensuring each project is tailored to the highest standards.
Mihail
Carpenter & Wood Expert
Mihail is Pecasa’s master craftsman with extensive expertise in carpentry and woodwork. He brings precision and skill to every garden room build, ensuring each structure is crafted with the highest standards of quality and workmanship.
Tudor
Carpenter
With years of experience in carpentry and construction, Tudor is an important part of the Pecasa team. His craftsmanship, attention to detail, and dedication to quality help ensure every garden room is built to the highest standard.
Tany
Electrical Engineer
With extensive experience in electrical installations, Tany ensures every Pecasa garden room is fitted with safe, efficient, and high-quality electrical systems. His expertise helps deliver reliable lighting, power, and heating solutions that make each space fully functional all year round.
Frequently Asked Questions
Most Pecasa garden rooms are installed in as little as two weeks once manufacturing is complete. The exact timeline depends on the size, specification, and site conditions, but our off-site precision manufacturing allows for significantly faster installation compared to traditional builds.
Many garden rooms fall under permitted development and do not require planning permission. However, this depends on factors such as size, height, and intended use. Pecasa provides guidance during the free survey to help homeowners understand their specific situation.
Yes. Pecasa garden rooms are built using Structural Insulated Panels (SIPs) and high-performance insulation, making them comfortable for use throughout the year — including winter months.
Pecasa includes many premium features as standard, such as plastered interiors, integrated lighting and electrics, quality flooring, EPDM roofing, and modern doors and glazing. This ensures transparent pricing and fewer unexpected extras.
Garden annexes can be used for independent living, guest accommodation, or multi-generational living, subject to planning and building regulations where applicable. Pecasa guides homeowners through the appropriate considerations during the design stage.
Yes. Every Pecasa garden room and annexe is fully bespoke. We do not use off-the-shelf templates — each building is designed around your space, requirements, and intended use.
Pecasa serves homeowners across London, Greater London, Watford, Hertfordshire, and surrounding UK regions. If you are unsure whether your location is covered, our team can advise.