A semi-paved surface is a type of surfacing that sits between unpaved and fully paved, such as asphalt or block paving: a water-permeable, half-open top layer. Rainwater can largely infiltrate through it.
Characteristics
There are two main forms. Unbound semi-paving consists of loose material that stays loose, such as gravel, grit, shells or granular aggregates. Bound semi-paving is held together with, for example, lime, cement or synthetic resin, creating a firmer but still permeable layer.
Advantages are its permeability, natural appearance and relatively low cost. Drawbacks are that it is less suitable for wheelchairs or walkers, and that it is prone to rutting, weeds and windblow. A good sub-base and a solid edge restraint are therefore important to keep the layer in place.
Applications
Semi-paved surfaces are used for footpaths, driveways, car parks, gardens and parks. They are popular where an informal, green appearance is wanted and where rainwater should infiltrate on site rather than run off into the sewer. Under heavy use or vehicle traffic, a careful build-up with a load-bearing sub-base is essential.
Related terms
- Gravel
- Grit
- Infiltration
- Permeable paving
- Edge restraint
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