Paver patio installation — an interlocking system, not a surface

Layout, pattern and the cut plan

The pattern is set before the first paver goes down, because it decides how many cuts there are and where they land. Running bond, herringbone and basketweave do not perform identically — herringbone resists rotation under load better, which is why it turns up on surfaces that take vehicles.

Watch for: A layout that puts thin slivers of cut paver along the most visible edge. A good installer works the pattern outward from a line that makes the cuts fall somewhere you do not look, and uses a border course to absorb them.

Base — built, then checked before it is covered

The compacted aggregate base is the load-carrying part, and once the sand goes over it nobody can inspect it again. On a paver job the base is also extended past the paving line, because the edge restraint has to sit on something solid.

Watch for: Base that stops exactly at the paving line. It is a small saving that guarantees the edge restraint has nothing to bite into, and the perimeter is where paver patios begin to fail.

The bedding layer — thin, uniform and screeded, never used to level

A shallow, consistent layer of coarse bedding sand is screeded over the finished base. Its job is to let each paver seat evenly, not to correct dips. The base is what gets you flat.

Watch for: A deep or variable sand layer used to bring a rough base up to level. It compacts unevenly under traffic and you get a wavy patio within a season or two. If you see the crew troweling sand into hollows, that is the tell.

Laying and cutting

Pavers are placed off the bedding rather than walked onto it, working from a straight edge or a string line so the courses stay true. Cuts are made at the perimeter and around any penetrations, then set.

Watch for: Dry cutting with no water and no dust extraction. Cutting concrete and stone produces respirable silica, and a crew that does not manage it is telling you something about their standards generally.

Edge restraint installed into compacted base

A restraint — plastic, aluminium, concrete haunch or a set border course — is fixed around the entire perimeter and pinned into the extended base. This is what stops the field spreading outward.

Watch for: Restraint spiked into soil or loose fill, or left off the side that faces a lawn "because the turf will hold it". Turf does not hold it. That edge is where the joints open first.

Joint sand and compaction

Sand is swept into the joints and the whole field is vibrated with a plate compactor over a protective mat, which seats the pavers into the bedding and drives sand down into the joints. It is usually repeated until the joints stop taking sand.

Watch for: A single sweep-and-go with no vibration, or joints that are visibly not full at handover. Half-filled joints mean the pavers are not yet locked to each other, which is the entire structural principle of the surface.

Jointing material choice and activation

Standard sand, or a polymeric jointing sand that binds when wetted. Polymeric resists washout and weed growth but has to be installed dry, in the right weather, and watered exactly as the manufacturer specifies.

Watch for: Polymeric sand installed on damp pavers or with rain coming. It hazes, stains the surface and sets hard where you did not want it, and removing that is unpleasant work. If the forecast is wrong, the right move is to postpone.

Handover, settling and the first season

You should be told what joint maintenance the surface needs, whether the product should be sealed at all, and what minor settlement is normal in the first freeze-thaw cycle. Some efflorescence — a white bloom from the concrete itself — is common on new pavers and generally fades.

Watch for: Being sold a sealer on day one as though it were structural. Sealing is a look-and-stain decision on most paver products, and sealing too early can trap efflorescence under the film.