What is the difference between resin ‘bound’ and resin ‘bonded’ surfacing?
Resin bound surfacing is a self-draining surface when laid on an open grade binder or drilled base. The resin bound mixture has tiny voids in the surface, allowing surface water to filter through the structure, making it a perfect permeable system for driveways, pathways, tree pits and areas which are prone to standing water. The smooth surface, with no loose stones, is ideal for wheelchair access and tough enough to withstand pressure washing.
By contrast, resin bonded surfacing is non-permeable and must be laid on a non-porous fine wearing course asphalt or concrete base. With resin bonded surfacing, soakaways and ECO drains may need to be installed to prevent excess water run-off.
‘Resin bonded’ is occasionally used as a generic term for both bound and bonded. This is misleading as the systems produce different results and something that we will never do.
What is resin bound (or “trowelled”) surfacing?
Resin bound surfaces are made from a mix of shingle, quartzite or crushed granite coated with a clear UV-stable polyurethane resin. To ensure that each aggregate particle is completely coated in resin, the two elements are combined in a specialist, forced action mix process to form a cold-pour mixture. The mix is then laid and hand-trowelled to form a smooth, compacted and level surface with no loose stones. It is recommended that a resin bound surface should be laid to a depth of 15mm for a pool surround, footpath or terrace and 18mm for a driveway and car park (Dimensions are approximate and may vary depending on site circumstance).
Bound = self-draining, smooth surface Compliant with SuDS regulations
What is resin bonded (or “scattercoat”) surfacing?
Resin bonded surfacing is made by sprinkling loose aggregate onto resin. It is a great, cost effective option for redevelopment projects or for giving a project an instant facelift. However, it isn’t quite as durable as resin bound paving; the bonded aggregate particles may loosen over time and the surface is not as easy to clean. Depending on the aggregate size [1-3mm], the depth is generally 3mm.
Bonded = non-permeable, rough surface Non-compliant with SuDS regulations (SuDS: Sustainable Underground Drainage Systems)