Wetpour Technical Information

Within this page lies information relevant to selecting the base preparation and type of install required for your surfacing requirements.

Download Wetpour fall height chart

download sub base specifications
Download Sub Structure specifications

Wetpour Critical Fall Height Chart

Existing hard surfaces

Abacus safety surfacing can be laid onto existing hard surfaces such as tarmacadam, concrete and paving slabs, eliminating costly sub-base preparations. The existing hard surface should be in good condition and clean of weeds, moss and debris. If the existing hard surface is not porous, the drilling of drainage holes may be required at regular intervals throughout the area. Should the existing surface be in goo, sound condition with no broken tarmac/concrete or uneven paving slabs, then a 20mm wearing course only layer of safety surfacing may be installed. To create a good, strong bond between the existing surface and the new safety surface a perimeter chase cut may be required. Abacus will confirm the suitability of existing surfaces during a site survey.

New Sub-base

Where new sub-base preparations are required the area should be excavated to a minimum depth of 150mm. A minimum thickness of 100mm MOT type 1 crushed stone should be compacted and regulated with local deviations no greater than 10mm under a 3 meter straight edge. The stone levels may range between 100mm and 300mm depending on site conditions. A perimeter edging is required to retain the surface. Abacus recommend precast concrete edgings, 150mm x 50mm, bedded and haunched on concrete, however a pre-treated or tantilised timber edge can also be used. The edging should be set above the level of the stone sub-base by the required thickness of Abacus safety surfacing. The thickness of safety surfacing will depend on the critical fall height of any fixed play equipment. The minimum thickness of Abacus safety surfacing to be laid onto a compacted stone sub-base is 40mm.

Structural Layer

Where abacus safety surfacing is to be laid at 20mm thickness e.g. under a low-level play equipment or for a multi-use games area (MUGA), a structural layer is required. This should be a porous, open textured macadam to a thickness of 50mm using aggregate of 10mm nominal size, this will allow the surface to drain freely. The macadam should have local deviations no greater than 7mm under a 3 meter straight edge. The structural layer must be completed a minimum of 14 days prior to installation of Abacus safety surfacing.

Wetpour Technical Groundworks