Natural stone paving: choosing the stone and laying it well

Sandstone is the most common paving stone in British gardens, either imported or quarried in Britain, including the Yorkstone seen in many northern towns. It has a warm, natural look, but it is porous: it takes up stains, grows algae in shade and varies from slab to slab. Limestone looks calmer and more even, but some limestones are softer and react to acidic cleaners.

Granite is dense, hard-wearing and suited to driveways and busy areas, often used as setts. Slate is striking and slip-resistant when riven, but the quality varies and cheap slate can flake. Reclaimed stone, particularly old York stone flags, is sought after in conservation areas and for period houses; it is thicker and uneven, which affects how it is laid.

Calibrated slabs are machined to a consistent thickness, which makes laying quicker and more predictable. Hand-cut or riven slabs vary in thickness, so the bed has to be adjusted slab by slab and the labour goes up. Reclaimed flags vary most of all and may need sorting on site, with a proportion unusable.

Ask the contractor to state which you are getting, the thickness range, and how much waste allowance is included, especially for random patterns where cutting increases.

Much natural stone sold in the UK is imported, and there have been long-standing concerns about working conditions in parts of the supply chain for some imported sandstone and granite. If that matters to you, ask the contractor and the supplier which quarry or region the stone comes from and what ethical sourcing assurance they can provide. British stone and reclaimed stone avoid part of the question but cost more.

Porous stone can draw moisture and salts up from the bed, which shows as dark patches or white bloom on the surface. Suppliers of many sandstones recommend priming the back of each slab before laying on a full mortar bed. Jointing matters too: the wrong mortar or a careless finish leaves smears that are very hard to remove from textured stone.

The contractor should also follow the stone supplier's advice on sealing. Some stones benefit from an impregnating sealer after they have dried out; others are better left unsealed. A sealer applied too early can trap moisture.

• stone type, finish, colour and origin
• slab sizes, thickness and pattern
• bed and priming method recommended for this stone
• jointing material and how the surface is protected during jointing
• sealing, if any, and when
• cleaning and care instructions for the first year

Cutting sandstone, granite and many other stones with a power saw releases respirable crystalline silica, which can cause serious lung disease. The Health and Safety Executive expects contractors to control it, for example with water suppression or on-tool extraction and suitable masks. Expect the contractor to cut with water or extraction, and keep children and pets away from the cutting area.

In a conservation area or at a listed building, the council may care about the stone used at the front of the house, and replacing historic flags or setts can need consent. Check before lifting anything old.

When you send a request through Offrano, it is offered without your name to paving contractors nearby, and exactly one can buy it. We email you its details before it sees yours. It costs you nothing, and there is no guarantee that a contractor takes the request.