There are a wide variety of materials available for constructing patios and driveways, from utilitarian concrete and tarmac to far more decorative paving slabs and blocks, gravel and stone chippings.
Natural stone slabs
Stone slabs or flags come in many shapes, sizes and colours. The main types of stone are natural stone and reconstructed stone. Natural stone is what its name implies and is the more expensive of the two; but natural stone slabs can vary in size and thickness and consequently will require a higher degree of expertise to lay.
Reconstructed stone slabs
Reconstructed stone slabs – sometimes described as reconstituted or artificial stone – are concrete units where a specific concrete mix has been designed to resemble natural stone. A wide range of natural stones can be imitated including Bath stone, Portland stone and red terracotta. Although they are the less expensive option, the quality can vary greatly and the cheapest stone slabs often bear little resemblance to the natural stone they are trying to imitate. So it’s advisable to look around to find the best supplier.
Block paving comprises of rectangular shaped blocks similar to bricks. The most common size for block pavers is 200mm x 100mm (8in x 4in) with a depth of around 65mm (2 ½ in). They can either be made of concrete or clay and come in a wide selection of colours. Clay paving blocks are more expensive than the concrete variety but both can be tumbled or polished.
Bricks and brick pavers
If using bricks to build a path, drive or patio they should be of a special quality to withstand harsh winter weather, especially frost. ‘F’ grade bricks are the most suitable. Thinner than bricks, brick pavers are usually square or have an interlocking shape.
Cobblestones are used for paving or edging. Cobbles have an old world charm but do produce an uneven surface, so may not be ideal in some situations. They are usually set in sand or mortar. Cobblestones are often used with other stone materials to create variation and contrast.
This is an ideal surface material for a driveway or parking area. Tarmac drains well and can look very neat, however this is usually a job best left to the professionals. Repairs to existing tarmac are simpler, and can be carried out using ready-mixed tarmac which is available in bags.
Small, round stones known as pea gravel with a diameter of either 10mm (3/8 in) or 20mm (3/4 in), which are spread loosely over a firm surface. It is advisable to have anchored edges to keep the gravel in place. Gravel can be white or various shades of brown. Although a gravel drive is very decorative it can be difficult to walk or push a pram across. Gravel should be laid about 25mm (1in) deep which means that 1 tonne of gravel will cover 15m2 (18yd2).
Stone chipping come in a variety of colours depending on the type of stone. Single coloured chippings or a combination of colours are available: white/grey limestone, red/grey granite, green/grey granite and golden flint. If planning to use stone chippings the sub-base should be made of well compacted hardcore about 100mm-150mm (4in-6in) deep. A 25kg bag of chippings will cover approximately 2.5m2 (3yd2).
Concrete provides an extremely tough surface. It is made up of sand, coarse aggregate and cement mixed together with water in specific proportions. For a drive the concrete should be laid 100mm-150mm (4in-6in) thick and for a path 50mm-75mm (2in-3in) thick. The concrete should be laid on compacted hardcore about 100mm (4in) deep for a drive. While a sub-base of compacted hardcore 25mm-50mm (1in-2in) will be sufficient for a path. Pigments can be added to the mix to produce a more attractive colour. However, the shade can vary from mix to mix making it difficult to achieve a uniform colour over the whole drive or path.
Paths, patios and driveways are strengthened and made to look neater with an edging or kerb which comes in a wide selection of attractive designs. Edging can come in lengths – called kerbs – between 600mm-900mm (2ft-3ft) long or as blocks. Edging can have tops that can be flat, rounded, chamfered, bullnosed and scalloped.