What to put under a garden room or pavilion

Why the base matters so much

Ground moisture is the number one enemy of anything built in a garden. If the base doesn't keep the room off the ground, or water collects underneath, timber and finishes suffer, doors stop closing properly and the whole thing can shift.

A well-planned base does three things: it keeps the room off the ground, keeps it level and lets rainwater drain away.

The most common options

• Concrete slab. The most solid, but it means building work: digging, formwork and waiting for it to cure. And it stays in your garden for good, even if the room is moved one day.
• Paving on compacted gravel. Simpler than concrete and drains well, as long as the ground is properly compacted and flat.
• Treated timber bearers or pallets. Cheap and quick for small, light sheds, but they don't last long in contact with damp ground.
• Adjustable supports. Feet that are raised or lowered until everything is level. No foundations needed, and air can flow underneath.

How Creixent does it: four supports, no foundations

Creixent, the garden pavilion we built by hand in Juneda (Catalonia), stands on four slender supports that level it whatever the terrain. The under-frame is set back from the walls, which is why the box seems to float in the air.

This has three advantages: no foundations are needed, the space underneath lets air circulate and, if you ever want to move it, your garden is left just as it was.

Before choosing the spot: a quick checklist

• Look for the flattest area you can find, one that doesn't flood when it rains.
• Leave space all around to clean and look after the walls.
• Check the trees: avoid large roots underneath or heavy branches overhead.
• Think about services: a fully equipped room like Creixent connects to the site's water, electricity and drainage.
• Check access: if it arrives by crane, the truck needs to be able to get close.

What about permits?

In Spain, every town hall has its own rules. Before placing any garden room or shed, ask your town hall what they require and, if possible, get the answer in writing.

If you'd like to see a garden pavilion that needs no foundations, the Creixent page has all the photos and the technical sheet.