Paving contractors glossary

Short, plain-English definitions of the terms you'll meet when choosing a paving contractor provider in Cheltenham.

What are edge restraints (kerbs and haunching)?: Edge restraints are fixed kerbs or concrete haunching placed along the perimeter of block paving to prevent the outer blocks from moving, spreading, or lifting.
What are flags (paving slabs)?: Flags (or paving slabs) are large, flat rectangular or square units made from concrete, natural stone, or porcelain, laid individually to form patio and outdoor surfaces.
What is a channel drain (ACO drain)?: A channel drain is a narrow, linear drainage system set flush or slightly recessed at the edge of a paved surface to intercept and divert surface water away from the area.
What is a laying course?: A laying course is a compacted sand layer placed over a sub-base to receive and bed paving blocks, flags, or setts, allowing them to be levelled and seated properly.
What is a soakaway?: An underground pit or chamber filled with permeable material that collects and disperses surface water runoff into the surrounding soil.
What is a sub-base?: A compacted layer of crushed stone or aggregate laid beneath paving surfaces to distribute vehicle loads and provide structural support.
What is a whacker plate (plate compactor)?: A whacker plate is a vibrating compaction tool that uses rapid downward strikes to compress soil, sand, and paving materials during ground preparation and landscaping installation.
What is block paving?: Block paving is a surface made from individual concrete or clay blocks laid in patterns over a compacted base, creating a flexible, permeable finish distinct from solid slabs or poured concrete.
What is calibrated paving?: Calibrated paving consists of stone or concrete slabs machined to an even, consistent thickness, enabling level laying and reducing lippage between adjacent stones.
What is falls and gradient?: Falls and gradient refers to the intentional slope built into a paved surface to direct rainwater toward drainage points and away from buildings and structures.
What is Indian sandstone?: Indian sandstone is a naturally split paving stone quarried in India and imported for outdoor patios, valued for its warm colours and uniform thickness calibration.
What is kiln dried sand?: Kiln dried sand is a specially heated, moisture-free sand used to fill the joints between block paving units, locking them together and preventing them from shifting.
What is MOT Type 1?: MOT Type 1 is a graded crushed aggregate material used as a compacted sub-base layer in road, driveway, and paving construction to provide structural support and stability.
What is permeable paving?: Permeable paving is a surface material or system designed to allow water to pass through the paving itself or its joints and infiltrate into the ground, rather than creating surface runoff.
What is planning permission for driveways?: Planning permission is formal consent required from the local council before building or resurfacing a driveway, typically needed when the surface area exceeds 5 square metres of non-permeable material.
What is porcelain paving?: Porcelain paving is a dense, fired ceramic slab with low water absorption and high frost resistance, commonly used for outdoor patios and terraces.
What is resin bonded paving?: Resin bonded paving is a surfacing technique in which loose aggregate stones are scattered onto a wet resin base coat, bonding as they cure to form a textured, permeable surface.
What is resin bound paving?: Resin bound paving is a decorative, permeable surfacing material made by mixing coloured aggregate with clear epoxy or polyurethane resin and trowelling it into a smooth finish on a prepared base.
What is riven vs sawn finish?: Riven finish is a naturally split stone surface with an uneven, textured face, while sawn finish is machine-cut to a smooth, uniform appearance with consistent thickness and edges.
What is sharp sand vs building sand?: Sharp sand is a coarse-grained sand used in bedding layers and mortar mixes for paving, while building sand is a finer grade used for general fills and pointing.
What is stone mastic asphalt (SMA)?: Stone mastic asphalt (SMA) is a gap-graded asphalt mix composed of coarse aggregate, filler, and high binder content, designed to resist rutting and deformation under heavy traffic loads.
What is SuDS (Sustainable drainage systems)?: SuDS is a planning and design framework for managing surface water runoff on residential and commercial properties, requiring drainage solutions that mimic natural water absorption rather than rapid runoff to sewers.
What is tarmac (asphalt)?: Tarmac (asphalt) is a flexible paving material made by mixing crushed stone aggregate with hot bitumen binder, commonly used for driveways, car parks, and roads.
What is thermoplastic line marking?: Thermoplastic line marking is a durable painted surface material melted onto car park surfaces to create parking bay divisions, directional arrows, and hazard warnings.