Glossary - Laying Paving

Pavement

Any surfaced construction used to carry foot or vehicular traffic. It includes footpaths, patios, roads, driveways, motorways, and even airport runways.

Sub-grade

The sub-grade layer is essentially the existing ground, cleared of any organic material. This may or may not require preparatory work, depending on chosen paving type and existing ground conditions.

Sub-base

The main load bearing layer of a path, road or driveway.

MOT Type 1

Sub-base to an agreed specification; a graded crushed material conforming to Dept of Transport Clause 503 for Highways.

Sharp Sand

A free-draining gritty sand that is free from clay and salts and does not retain water.  Angular particle shape allows for a better interlock and hence stability with low proportions of silt. Best used for bedding.

Building Sand

A finer (smaller particle size) than sharp sand, most often used for mortars.  The particle shaped tends to be more “rounded” allowing for better workability in the mixed mortar.

Mortar

A mix of building sand (5 parts) and cement (1 part) mixed with sufficient water to allow for a moist consistency; neither too runny nor too dry.  May be used in paving and walling applications.  Once set the mortar binds together the adjacent pieces of stone.

Bedding

Generally accepted as a lean mix mortar to allow the paving to “bed” into the mix allowing it to set and prevent future movement of the pavement.

Spot bedding

The method of applying the mortar mix in several spots rather than as a full bed.  Not a recommended method since it allows for water ingress beneath the paved surface, may lead to weakness and (in the case of porous materials) lead to surface spotting.

Screed

A thin, top layer of material laid over a concrete subfloor, that is traditionally made of sharp sand and cement, similarly to concrete.

Drainage

All paving should be designed to drain freely to gullies or other disposal points. Recommended fall is usually quoted as 1 in 40; In practice, 1 in 80 is adequate for smaller, domestic areas; 1 in 60 is most often recommended for domestic applications.

Fall

The gradient or slope to allow for drainage of the surface of a paved area from the highest to lowest point on a paved surface.

Buttering

The application of mortar or bedding to the free end of a flagstone / brick / block prior to placement of the adjacent piece.  Allows for the jointing or spacing to be part filled prior to pointing.

Pointing

The finishing of a pavement or wall to complete the jointing between adjacent pieces.  Often completed with a slightly wetter mortar than the bedding and compacted with use of trowel or jointing iron.

Sealing

Use of chemicals / surface coatings to protect or enhance the appearance of a product.

Spacing (widths)

Whilst possibly a matter of personal preference larger spacing say 10mm to 12mm between paving tends to be used with large formats and where using mortar to point.  Smaller spacing say 3mm to 6mm tends to be used with smaller format products – e.g. Setts, and typically where sand is being used to complete the paving.

Butt Joints

The placement of one item of paving immediately adjacent to the next. More readily seen and achieved with sawn sided materials or cast stone with little variation in dimension; more difficult with naturally split material where the irregularities might cause variations.

Crazy Paving

Completely random pieces of stone with no specification.

Laying Patterns

An outline of laying such that the “pattern” tends to repeat – usually applied when a mix of sizes are used in conjunction with each other.

Stretcher Bond

A laying system similar to that observed in brickwork, the joint between adjacent pieces on one row is at the halfway point of the pieces on the next row – above and below.

Herringbone

The laying system most often seen in “parquet” flooring – a “v” is formed by 2 pieces and the pattern repeats across the area laid.

Broken Bond

Similar approach to Stretcher Bond but the jointing does not necessarily align with mid-point of next row.  Tends to be used in laying patterns where the units are of fixed width but random or varying length.

Random

No fixed jointing or laying pattern.