Preparing the Ground for Your Garden Shed
- Cambrige Garden Sheds
- May 7
- 7 min read
A Good Shed Starts with the Ground
The base is not the exciting part of a garden shed. People notice the timber, the roof, the doors, the colour and the details. But the quiet, practical things underneath are what allow the visible parts to last.
A good shed should feel settled in the garden. It should stand properly, open and close properly, and do its job without becoming a problem later. That begins with the ground it stands on.
Why the Ground Matters
A good shed needs good ground beneath it. It is not the most romantic part of choosing a garden building, and it is rarely the part people get excited about, but it is one of the things that decides whether the shed will sit properly, work properly and last properly.
A shed is a small building, but it is still a building. It needs to stand level, it needs to be supported evenly, and it needs to be kept away from sitting water and soft ground. If the base is not right, problems can appear later. Doors may start to catch, the frame can twist slightly, water may collect where it should not, and the whole building can begin to feel less settled than it should.
Choosing the Right Base for Your Garden
There is no single correct base for every shed. The right answer depends on the garden, the shed and how the building will be used.
A small storage shed at the end of a dry, level garden may not need the same preparation as a larger insulated building intended for regular use. Some customers want a permanent concrete base. Others prefer ground screws because they are cleaner and less disruptive. Some already have a patio or hardstanding that may be suitable. Others want to prepare the ground themselves.
What matters is that the shed has a proper starting point. Once the ground is prepared well, everything else has a better chance of working as it should. The building sits square, the doors work properly, water drains away, and the structure is not fighting movement underneath it
Enabling Works
For customers who would rather not deal with the preparation themselves, we can usually help with the enabling works. This is the work needed to make the site ready before the shed is installed.
Depending on the garden, this might mean clearing the area, levelling the ground, preparing a base, installing ground screws, building a timber subframe, or advising on the most suitable foundation for the site. The exact work depends on the site conditions, access, ground levels and the size of the shed.
Some gardens are straightforward. Others have awkward levels, poor drainage, difficult access, old concrete, roots, rubble or hidden services. We are happy to look at the site and advise on the most sensible route.
Does Every Shed Need a Concrete Base?
Not every shed needs a concrete base. Concrete can be a very good option, especially for larger buildings or where a very permanent foundation is wanted, but it is not the only answer. Many gardens are better suited to other approaches, particularly where access is limited, where the client wants less disruption, or where a lighter-touch foundation makes more sense.
The right base depends on the size of the shed, the condition of the ground, the way the building will be used and the character of the garden itself. A small storage shed on firm, level ground may need a different approach from a larger insulated garden building intended for regular use throughout the year.
Concrete Slabs or a Concrete Base
Concrete is still a sensible choice in many situations. A well-made concrete base gives a solid, level foundation and can be especially useful for larger sheds, heavier use, or sites where a permanent base is wanted.
The important words are “well-made”. A concrete base needs to be level, stable, correctly sized and positioned so that water does not sit against the timber. A badly made concrete base can cause just as many problems as no base at all.
Some customers already have a suitable concrete area in place. Others may choose to have one made before installation. In either case, we would need to check that it is appropriate for the size and design of the shed.
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Ground Screws
Ground screws are a good alternative to concrete in many situations. They are metal screw foundations installed into the ground to create strong support points for the shed, without the need to dig out and pour a full concrete slab.
In the right conditions, ground screws can be clean, practical and relatively low-disruption. They can work particularly well where access is limited, where you want to avoid wet concrete, or where a lighter-touch foundation system is preferred. They also allow airflow beneath the building, which can be helpful for timber structures.
They are not right for every site. Very poor ground, hidden rubble, large roots, drains or awkward levels may need to be assessed first. But where the ground is suitable, ground screws can be an excellent way to support a garden shed without building a full concrete base.
Timber Bases
A timber base can work well, especially for smaller sheds or where a full concrete base is not wanted. It can be a practical way to create a level platform, particularly where the ground has slight changes in level.
The mistake is to think of a timber base as simply putting a few pieces of wood on the ground. A proper timber base still needs to be supported evenly, kept away from sitting damp, and built so that the shed has a stable platform beneath it.
Done well, it can be a neat and practical solution. Done badly, it becomes a weak point. For larger sheds, heavier use or wetter ground, we may recommend another option.
Preparing the Ground Yourself
Some customers prefer to prepare the ground themselves, and that is perfectly possible. If you want to do this, the most important thing is that the site is level, stable, correctly sized and ready before the shed is delivered and installed.
The first thing to mark out is the footprint of the shed. We recommend setting out the exact shed size on the ground, then allowing a little working space around it so the building can be installed properly. This can be done with string lines, timber pegs, spray marker or even temporary boards laid out to show the corners. The important thing is that the area is square, measured diagonally from corner to corner, and not just judged by eye.
The finished base should be level across the whole footprint. A small slope in the garden may not look dramatic, but over the width of a shed it can make a real difference. The easiest way to check this is with a long spirit level on a straight timber, or ideally with a laser level. Measure from the same reference point at each corner, and check the levels across the front, back, sides and diagonals. The shed needs to sit on a flat, even plane, not on four random high points.
The height of the base is also important. The shed should not sit below the surrounding ground, where rainwater can run towards it or collect around the timber. In most cases, the finished base should sit slightly proud of the surrounding ground, with the area around it falling gently away where possible. The aim is simple: water should drain away from the building, not towards it.
If you are preparing a compacted hardcore base, the ground should be dug out to a suitable depth, filled with compacted MOT Type 1 or similar material, and compacted properly in layers rather than simply tipped in and flattened. If slabs are being used, they need to be laid onto a stable, compacted base and checked carefully for level. If a timber subframe is being used, it still needs proper support beneath it and should not be left sitting directly in wet soil.
It is also important to think about access. The route from the road or driveway to the shed position needs to be clear enough for materials and large panels to be carried through safely. Narrow gates, steps, tight corners, overhanging branches, raised beds and fragile paving can all affect installation. If there is limited access, it is better to know before the installation day.
Before we arrive, the site should be clear of old sheds, roots, loose rubble, soft soil, garden waste and anything that might prevent the shed from sitting properly. If there are drains, cables, pipes, inspection covers or large tree roots nearby, these should be mentioned in advance. They may affect the choice of base or the exact position of the shed.
Preparing the ground yourself can be a good way to keep costs down, but it does need to be done accurately. A shed base does not need to be complicated, but it does need to be level, square, stable and able to drain properly. If the base is not suitable on the day of installation, we may not be able to install the shed safely or correctly.
DIY Shed Base Checklist
Before installation, the shed area should be level, square, stable and ready to build on. The finished base should be slightly raised above the surrounding ground where possible, so water can drain away from the building rather than sitting around the timber.
Mark out the exact footprint of the shed and check it carefully before preparing the base. Measure the width and length, then measure diagonally from corner to corner to make sure the area is square. If both diagonal measurements are the same, the base is square.
Check the levels across the whole area, not just at the corners. A long spirit level on a straight piece of timber can work well, but a laser level is better if you have one. Check the front, back, sides and diagonals so the shed sits on one flat, even plane.
The ground beneath the base should be firm and well compacted. Soft soil, loose rubble, freshly disturbed ground or areas that hold water are not suitable without further preparation. If using compacted hardcore, it should be built up and compacted properly in layers.
Make sure there is a clear access route for installation. Gates, steps, narrow paths, tight corners, raised beds, overhanging branches and fragile paving can all affect how easily the shed can be brought through and installed.
The area should be fully cleared before installation day. Old sheds, roots, loose stones, garden waste and anything else in the way should be removed. If there are drains, cables, pipes, inspection covers or large tree roots nearby, please let us know before we arrive.
A DIY base does not need to be complicated, but it does need to be accurate. The important things are simple: level, square, stable, slightly raised, free-draining and accessible.
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