Transform your outdoor space with high-performance, fully insulated garden buildings — expertly designed, locally manufactured, and installed in as little as two weeks.
✔ Free Site Survey
✔ Free 3D Design
✔ Fully Bespoke Builds
✔ Premium Materials as Standard
Bespoke Garden Rooms & Annexes Built for Modern Living
At Pecasa, we design and build premium bespoke garden rooms and garden annexes for homeowners across London and the UK. Our buildings are engineered for year-round comfort using advanced SIPs construction, ground screw foundations, and high-performance insulation.
Whether you need a garden office, guest annexe, home gym, or multi-purpose outdoor living space, Pecasa delivers fully customised solutions — manufactured locally and installed with speed, precision, and minimal disruption.
Bespoke Garden Rooms & Annexes Built for Modern Living
Built for Year-Round Living
Every Pecasa garden room is fully insulated using Structural Insulated Panels (SIPs), helping maintain warmth in winter and comfort in summer — not just a seasonal garden building.
Truly Bespoke Design
No templates. No off-the-shelf boxes. Every garden room and annexe is designed around your space, your lifestyle, and your exact requirements.
Fast, Professional Installation
Our precision manufacturing process allows most garden rooms to be installed in as little as two weeks, with minimal disruption to your home.
Premium Specification as Standard
Unlike many providers, key features such as plastered interiors, flooring, lighting, and climate control options are included as standard — delivering real value and transparency.
Our Garden Building Solutions
Bespoke Garden Rooms
Create the perfect garden office, studio, gym, or relaxation space with a fully insulated, modern garden room built to your exact specifications.
Ideal for:
- Home offices
- Garden gyms
- Creative studios
- Entertainment spaces
Garden Annexes (Granny 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.
Pecasa combines modern construction technology with expert craftsmanship to deliver garden buildings that exceed typical market standards. Our focus on structural quality, thermal performance, and transparent specifications ensures homeowners receive genuine long-term value.
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.
About Pecasa Garden Rooms
Pecasa is a UK-based specialist in bespoke garden rooms and garden annexes, serving homeowners across London and surrounding regions. The company designs, manufactures, and installs fully insulated garden buildings using SIPs construction, ground screw foundations, and premium materials as standard.
Contact us today to book your free consultation.
Pecasa Premium Garden Rooms and Annexes are cost effective, fully insulated practical space solutions to expanding your home, adding a quality environmentally friendly, sustainable and energy efficient space for year round use.
Two Week Installation
Sustainability
High Quality British Manufactured
Fully Customisable
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.