Patio Installation: What a Good Job Involves

Patio cost factors by material

Material choice changes the preparation, laying method and finishing work, but a reliable price also needs the site levels, access and drainage.

Patio materials and quote factors. Material | Main quote factors | Notes. Concrete slab — Slab size, pattern and ground preparation — Practical option with varied finishes; Natural sandstone — Stone variation, sorting, cutting and sealing — Traditional appearance, needs sealing; Porcelain — Precise base, cuts, primer and joint detailing — Low maintenance, demands a very flat base Access, excavation, levels, steps, walls, drainage and waste removal all affect the final quote.

Excavation and sub-base

Most patio failures start underground. Topsoil and roots are removed down to firm ground, then a granular sub-base is laid in layers and compacted with a plate compactor. The depth depends on the soil; clay that moves with the seasons usually needs more than free-draining ground.

Skipping or skimping this stage is the usual reason slabs rock, sink or crack within a few winters. It is also why a cheap quote that says little about the base deserves questions.

Falls, levels and drainage

A patio should fall gently away from the house so rain runs off rather than towards the walls. It also needs to finish at least two brick courses below the damp-proof course, otherwise splashing and standing water can bridge it and cause damp inside.

Where the garden slopes towards the house, or the patio runs to a door threshold, a channel drain or soakaway may be needed. Large paved areas can also add to surface water, so permeable designs or drainage into the garden are worth considering.

Fall away from the building, typically a gentle gradient · Finished level below the damp-proof course · Channel drain at thresholds where levels are tight · A route for water to go: soakaway, border or existing drain

Laying the slabs

Natural stone and concrete slabs are normally laid on a full mortar bed so there are no hollow spots underneath. Porcelain is thin and dense, so it needs a priming slurry on the back of each slab to bond properly, and a very flat bed because it will not hide unevenness.

Joints are then filled with a pointing mortar or a jointing compound. Gaps that are consistent, and pointing that is flush and full, are good signs of a careful installer.

Choosing a material

Sandstone gives a traditional look that weathers well but needs sealing and occasional cleaning. Porcelain resists staining and algae, suits modern houses and is easy to keep clean, but costs more and needs more precise laying. Concrete slabs suit a tight budget or a utility area. Matching the patio to indoor floor tiles through large glazed doors is a popular choice with porcelain.

How long a patio takes

A typical garden patio takes from a few days to a couple of weeks, depending on size, access, levels and whether walls, steps or drainage are included. Wheelbarrow-only access through a house or narrow side passage adds time because every tonne of spoil and sub-base has to move by hand.

Frequently asked questions

How much does a patio cost per m²?

A reliable figure needs the area, access, excavation depth, ground condition, drainage, levels, steps and chosen material. Porcelain also needs a particularly precise base and laying method.

How deep should a patio sub-base be?

It depends on the soil. The aim is firm ground beneath a compacted granular layer; clay soils usually need a deeper base than free-draining ground.

How far below the damp-proof course should a patio be?

At least two brick courses below it, so rain splash and standing water cannot bridge the damp-proof course.

Is porcelain better than sandstone for a patio?

Porcelain is lower maintenance and resists staining but costs more and needs a very precise base. Sandstone is traditional and forgiving but needs sealing.