Most of the work is hidden underneath

When a patio looks good ten summers later, it is almost always because of the ground preparation, not the slabs. Paving only stays flat if it sits on a firm, even base that does not move when it gets wet, frozen or walked on. That is why a quick job with slabs set straight on soil tends to sink, rock and crack. Understanding the stages helps you ask the right questions when you compare quotes, and spot a shortcut before it becomes a problem.

Marking out and deciding the levels

The first job is to mark the shape on the ground and decide the finished height. The patio should sit below the damp-proof course of the house, with a gentle slope away from the walls so rain runs off rather than towards doors and airbricks. Many Birmingham gardens slope or have uneven ground, so levels are worked out with string lines and a spirit level before any digging. Getting this right early avoids steps in the wrong place or standing water later.

Digging out and building the sub-base

Next the area is dug to a depth that allows for the base, the bedding layer and the paving itself. Soft spots, roots and old rubble are removed. A layer of hardcore or crushed stone is then spread and compacted in stages with a plate compactor, because a thick layer compacted in one go will settle later. On heavy clay, the base matters even more, as clay swells and shrinks with the weather. The spoil and waste can be taken away so the garden is not left with piles of earth.

Bedding and laying the paving

On top of the compacted base goes a bedding layer, which is levelled carefully so each slab can be set at the right height. Slabs are laid one at a time, tapped down and checked constantly against the string lines and the fall. Larger or porcelain slabs need particular care, as they have little tolerance for a poorly prepared base. Cutting is done neatly so edges at walls, steps and borders look deliberate rather than patched, and the pattern is planned to avoid thin awkward slivers.

  • Check the fall away from the house with a level at every stage.
  • Lay slabs from a fixed line and keep joints even.
  • Cut edges cleanly where the patio meets walls and steps.

Pointing and finishing

Once the paving is down, the joints are filled so that weeds, ants and water cannot get in and so that the slabs lock together. The choice of jointing material depends on the paving type and how the area will be used. Excess is brushed off and the surface is cleaned before anyone walks on it. Finally, the edges are tidied, any borders and lawns are made good against the new patio, and the leftover materials and rubbish are cleared away. Give the work time to settle before heavy furniture goes on.

What to ask when you compare quotes

Ask what the base is made of, how deep it will be, how the fall will be set and what happens to the old paving and soil. A professional will happily explain each stage. Be wary of anything that skips the compacted base or lays slabs directly on sand. Cost depends on the size, the access for machinery, the depth of digging, the waste to remove and the paving chosen, so the reliable way to know is to have someone see the garden.

Want it looked at properly?

Tell us what you have and we will arrange to visit, explain what is needed and give you a free, no-obligation quote. See our patio construction page, or send us photos on WhatsApp.

Common Questions

Why do some patios sink or crack?

Usually the base is the cause. If paving is laid on soft ground, thin bedding or an uncompacted layer, it moves as the ground gets wet, dries or freezes. Roots, poor drainage and heavy loads make it worse. A properly compacted sub-base and an even bedding layer are the strongest protection against settling.

Does a patio need a slope?

Yes. A gentle fall away from the house lets rainwater run off instead of pooling on the paving or against the walls. It is small enough that you will not notice it when you sit down, but it makes a real difference to drainage, algae and frost damage.

How deep does the ground need to be dug?

It depends on the paving, the bedding and the ground itself, so there is no single figure. The dig has to leave room for a compacted base, a bedding layer and the slab, and soft or heavy ground may need more. We look at the garden before recommending a depth.

Can you take away the old paving and soil?

Yes. Old slabs, rubble and spoil can be removed as part of the job, and the area is left tidy. Waste affects the work involved, so it is worth mentioning when you ask us to look at the garden, along with any access difficulties.