Patios in Sixpenny Handley, digging on the chalk

What comes out. Old paving, its bedding, any old concrete and the topsoil are excavated back to a firm formation. Up here that formation is often chalk, sometimes with a cap of clay with flints over it, and the spoil is bulky. It goes by the load, and the muck away is a proper line on the quote rather than something absorbed into a rate.

Protecting the formation. Chalk is strong while it is intact and it is ruined by water and by traffic. Left open in the rain the surface turns to slurry, and once it has done that no amount of whacking will bring it back. So we dig what we can build the same week, cover it if the weather turns, and keep the barrow runs off the exposed formation.

The sub base. MOT Type 1 in thin lifts, whacked to full compaction, taken out past the edge of the paving, with a geotextile separator between the stone and the subsoil. The separator earns its keep here because it stops fines being pumped up into the hardcore when the ground is wet.

Full mortar bed. Slabs go on a full wet bed with a slurry primer on the back. Dabs leave voids, and on ground that holds water in the winter and shrinks back in a dry summer a void is the beginning of a rocking slab.

The paving itself. Porcelain is calibrated and consistent, needs no sealing and stays clean. Sandstone is riven and warm and each slab is bedded to its own thickness. Limestone reads well against flint and chalk walling and shows marks more readily. Granite is the toughest of them. Travertine is a sheltered courtyard material rather than an exposed downland one.

Falls and the damp course. The terrace falls away from the house and finishes at least two courses below the DPC. Where a threshold is too low we dig down rather than build up, because bridging a damp course puts water into the wall. Approved Document C sets out the standard.

Drainage on chalk. Chalk will often take water readily, so a soakaway can work well here where it would not in a clay valley, but it has to be sited and sized rather than guessed. Otherwise it is a channel to a gully and an outfall, or a permeable build up over open graded stone that lets the runoff straight through the joints.

Edges, steps and jointing. A haunched edging or kerb where paving meets grass, a retaining edge with coping where a sloping garden is held back, and steps with equal risers. Joints are filled with a brush in resin compound worked wet and tooled off, or hand pointed on older stonework. Then the repairs: lifted slabs, a sunk bay, cracked stone, algae, efflorescence on new sandstone and staining.

No rate per square metre, because the slabs are the part you choose and the smallest part of the price.

Getting to it. A village cottage with a narrow side path, a farmhouse with a yard you can back a lorry into, and a modern house on a sloping plot are three different jobs. Everything comes in and goes out through the garden, often through a side gate or the house. A patio you can barrow to directly is a different job from one where every slab is carried. The work at height rules still apply to the dig and the machinery.

What is coming out before anything goes down. An old concrete slab, a raised bed, tree roots or made ground all have to be dug out and taken away, and that is priced by the load rather than by the metre. The dig is where a patio quote is won or lost.

Falls, levels and the damp course. A patio has to fall away from the house and finish at least two courses below the damp proof course, and getting that right often means steps, a retaining edge or a drainage channel. Laying a new patio up against a wall at the wrong level is the single most expensive mistake on this kind of job.

Comparing quotes? Ask how deep the dig goes and what sub base is specified, whether the slabs are laid on a full wet bed or on dabs, what the falls are and where the water goes, whether edgings and steps are included, and what the jointing compound is. Two quotes for the same job are usually two different jobs.

We cover Sixpenny Handley, Woodcutts, Pentridge and the Chase villages, broadly SP5, under Dorset Council. You are dealing with Bournemouth Roofing & Building, the trading name of Bournemouth Roofing & Building Ltd, registered in England and Wales, company number 15471719, which you can look up in a minute. Thomas Hannen's business, and he is the one who comes out to price the job, not a salesman. A verified customer's 10 out of 10 on Checkatrade. The visit and the written quote are both free.