Garden Room Foundation Systems

When creating your perfect garden room, the foundation is the unsung hero, providing the strength and stability your space needs to last for years to come!

At Green Retreats, we’ve continually refined our approach to building garden rooms, optimising our foundations to be more efficient and sustainable. Our innovative recycled plastic piling foundation system is the latest evolution, offering a cutting-edge, eco-friendly alternative to traditional concrete piles. Lighter, more efficient, and significantly better for the environment, this system builds upon the strength and reliability of our previous foundation methods while enhancing sustainability. Rigorously tested in real-world conditions for over five years represents our commitment to continuous improvement and innovation.

With more than 16,000 installations to date, an impressive 95% of our builds now rest on this smart, sustainable garden room foundations, proving that being eco-conscious doesn’t mean compromising on quality. It’s the future of garden room construction, and it starts from the ground up.

What Sets Our Garden Room Foundation System Apart?

Traditional concrete piles come with a high environmental cost, but our garden room foundation offers a smarter, more sustainable alternative. Made from 80-90% recycled HDPE plastic, our piles are sourced from local recycling suppliers, ground down, and injection-moulded. This closed-loop process minimises waste, reduces our carbon footprint, and ensures a durable, eco-friendly foundation for your garden room.

Preparing the Base – We carefully excavate to a depth of 300-600mm, ensuring a stable foundation for the pile. In most cases, we aim for at least 400mm when soil conditions allow, providing optimal support. 

Adding a Small Concrete Base – A minimal but effective amount of concrete is poured into the base of the hole, creating a sturdy and durable foundation for the pile. This step helps distribute the load evenly and enhances the overall stability of the structure. 

Placing the Plastic Pile – The recycled plastic crate, designed for strength and sustainability, is carefully positioned within the hole. This step ensures proper alignment and a secure fit, which is crucial for maintaining the integrity of the structure over time. The use of recycled materials not only provides durability but also supports environmentally friendly construction practices.

Backfilling with Soil – Once the concrete has set and the pile is secure, we refill the surrounding area with the excavated soil. The backfilling is done in layers, compacting the soil as needed to ensure stability and prevent shifting over time.

The Key Benefits of Our Garden Room Foundation System

Choosing the right garden room foundation is about more than just stability; it’s about long-term durability, energy efficiency, and environmental impact. Our innovative recycled plastic piling system redefines what a foundation can be, offering a smarter, greener alternative to traditional concrete bases. Here’s why our system outperforms the rest:

1. Superior Insulation and Damp Protection

Our plastic foundation system doesn’t conduct cold, keeping your garden room warmer in winter and dry year-round. Placed at 1-meter intervals, the foundations distribute the load over steel composite insulated panels. Plastic crates and steel skins prevent cold bridging and dampness, ensuring maximum thermal efficiency.

2. Exceptional Strength and Stability

Precision matters. Our foundations are spaced exactly one meter apart, ensuring even weight distribution and rock-solid stability for your structure.

3. Eco-Friendly and Sustainable Choice

By minimising concrete use, reducing soil transportation, and significantly cutting CO₂ emissions, our system supports a greener, more sustainable future without compromising on strength.

4. Maximised Internal Height

Our unique design allows for the tallest internal ceilings on the market while keeping the overall structure low to the ground for a sleek, unobtrusive appearance.

Why not browse our garden rooms with maximised internal height!

View The A Range

How Other Foundation Methods Compare

While there are other foundation options, they often come with compromises:

Ground screws

Ground screws are expensive and require high-quality steel, which must be extracted, manufactured, and shipped worldwide. To prevent corrosion, they need to be galvanised, which has a negative environmental impact. For proper performance, ground screws must be at least 800mm deep in good soil, though typically, they should be between 1.05m and 1.75m. Many garden room manufacturers do not conduct proper soil testing for each location, increasing the risk of failure. To cut costs, they often use fewer screws than recommended, which can compromise safety. Always insist on a load test report before installation to ensure stability for your garden room foundation.

Plinths

Plinths are another costly option, requiring three times more concrete than alternative solutions. Due to their weight, they demand more fuel and energy for transportation and installation, contributing to higher emissions. They also generate significantly more site waste, increasing disposal requirements.

Concrete base

A concrete base is a permanent solution that cannot be altered or moved. It consumes large amounts of energy and materials, making it less sustainable. The process is slow and messy, with long setting times that can disrupt the site. Managing contractors for the installation adds complexity and can extend the overall build duration.

With over 16,000 installations, our tried-and-tested garden room foundation system is the best choice for a smarter, more sustainable garden room—proving that innovation and eco-conscious design go hand in hand.