A well-laid patio, driveway or garden path can transform the look of your outdoor space. But even the most carefully installed paving can start to move or sink over time if the base isn’t stable or if water and frost are allowed to do their work underneath. Fortunately, with the right preparation and maintenance, you can keep your paving looking neat and level for many years. Here’s a practical guide to help you keep your slabs firmly in place.

Start with a Solid Foundation

The key to long-lasting paving is a stable base. Most problems with uneven or shifting slabs come from cutting corners during the groundwork.

• Dig deep enough – usually around 150–200 mm for a patio and 250–300 mm for a driveway, depending on the soil type.
• Lay a sub-base of compacted MOT Type 1 or crushed stone – compact it in layers of about 50 mm using a vibrating plate compactor to ensure it’s firm and even.
• Finish with a sharp sand bedding layer – about 30–50 mm thick. This layer should be level and smooth, but not compacted before the slabs are laid.

A solid foundation prevents the paving from sinking or shifting as the ground settles or the weather changes.

Ensure Proper Drainage and Fall

Water is one of the biggest enemies of paving. If rainwater can’t drain away, it will collect beneath the slabs and gradually destabilise the base.

Make sure your paving has a fall of around 1:60 (about 16 mm per metre) away from buildings so that water runs off easily. In areas with heavy rainfall or clay soil, consider installing a soakaway or drainage channel to handle excess water.

Avoid using very fine sand for the bedding layer, as it retains moisture. Coarser sharp sand or grit sand provides better drainage and stability.

Use Edge Restraints

Even a perfectly laid surface can start to spread if the edges aren’t secured. Edge restraints act like a frame, keeping the slabs locked in place.

You can use concrete edging, steel edging, or robust kerb stones, depending on the look and load of the area. Make sure the edging is set firmly in concrete or compacted sub-base material so it doesn’t move. This is especially important for driveways, where vehicle weight can push the paving outwards.

Fill the Joints Properly

The joints between slabs do more than just look tidy – they help stabilise the surface. When jointing material washes out or weeds take hold, the slabs lose support and can start to wobble.

Use jointing sand or kiln-dried sand, and brush it thoroughly into the gaps. Refill as needed, especially during the first few months as the sand settles. If you want to reduce weed growth, consider a polymeric jointing compound that hardens slightly while still allowing water to drain through.

Protect Against Frost Damage

Frost can cause the ground to heave and create uneven surfaces, particularly if water is trapped beneath the slabs. Good drainage and a well-compacted base are your best defences.

In colder parts of the UK, it’s worth using frost-resistant sub-base materials and avoiding anything that holds water. Keep the surface clear of leaves and debris in winter, as these trap moisture and increase the risk of frost damage.

Maintain Regularly

Even the best paving needs a bit of care. Sweep regularly to remove dirt and debris, pull out weeds, and top up the jointing sand when necessary. If you notice a slab starting to rock or sink, lift it, adjust the sand bed, and relay it before the problem spreads.

A quick inspection each spring can help you catch small issues early and avoid costly repairs later.

A Lasting Investment

A stable, well-maintained paved area isn’t just about looks – it’s an investment in durability and function. With a solid foundation, proper drainage, and regular upkeep, your paving will stay level and attractive for years to come.

It takes a bit of extra effort at the start, but the result is a surface that looks great and stands up to everyday use – whether it’s a patio, pathway, or driveway.