What Are Groundworks? A Plain-English Guide

What do groundworks include?

Groundworks is the preparation work at and below ground level: getting the ground sound, level and draining before anything is built on it. On a typical domestic job that means clearing the site, excavating and carting away the spoil, sorting levels and drainage, and laying a compacted sub-base or foundations for whatever goes on top, whether that is a driveway, a patio, a building or a garden. The usual tasks:

Why do groundworks matter so much?

Because everything built afterwards sits on them, and ground that moves or holds water will break whatever is on it. A driveway sinks, a patio cracks, a wall leans, a floor heaves. Almost every failure we are called out to put right traces back to the groundwork, not the surface, which is why it is the part we spend most of a job on.

It is also the part that is hardest and most expensive to fix later, because it is buried under the finished job. Spending properly on the ground is the cheapest insurance there is: done once and done well, it never has to be touched again.

When do you need groundworks?

Any time something is being built on or into the ground. A new driveway or patio needs a dug-out, compacted base. A retaining wall needs a foundation. An extension needs footings and often drainage. Even a new lawn on heavy ground needs the drainage and levels sorting first. If it sits on the earth, the earth needs preparing.

The bigger or heavier the thing on top, and the softer or wetter the ground, the more the groundworks matter. On a sloping or poorly drained plot, they are the majority of the job.

Do groundworks near a drain or sewer need permission?

Sometimes. Work that goes over or within three metres of a public sewer generally needs the water company's permission through a build-over application, and building control will want to see it before a build is signed off. In this area the water company is Southern Water. Existing drains are not always where the plans say, so part of doing groundworks properly is checking what is actually in the ground.

Planning permission is a separate question that depends on what is being built on top. Our guide to garden planning permission covers the driveway, wall, decking and patio rules; for anything structural, check with your local authority before you start.

How long do groundworks take?

It varies far more than the surface work does, because it depends on how much has to come out of the ground and what you find when you open it up. On a straightforward job it can be a day or two; on a sloping plot, a wet one, or one with a lot of spoil to remove, it is the bulk of the whole project's timescale.

That is why we look at the site and the ground before we put a time or a price to a job, and why, on the rare occasion the ground turns out differently once it is open, we stop, show you, and agree the change with you before carrying on rather than at the end.

Do you do groundworks for builders and extensions?

Yes. Alongside driveways, patios and garden projects, we take on groundworks for builders: footings, site preparation, drainage dig-outs and the base a build sits on. With more than twenty-five years in groundworks behind the team, it is the part of every job we care most about getting right.

Whether it is the foundation for an extension, the sub-base under a new driveway, or sorting the levels and drainage on a whole garden, it is the same careful, ground-up approach. You can see more on our groundworks page.