Resin Bound/Bonded Aggregates
The terms, ‘resin bonded’ and ‘resin bound’ finishes to driveways, car parks and pathways are
sometimes confused as being one and the same product/technique. Theoretically, both use the
same materials, but in different ways.
Resin bonded is the term used to describe the operations involved in spreading resin over the
base, then dressing aggregate (usually 5mm clean stone) so that the surface dressed stones are
bonded into, yet remain on top of the resin.
Resin bound is the term used to describe the operations involved in spreading a 15 – 25mm
deep layer of pre-mixed resin and aggregate – mixed following strict measurements, timings
and temperature/moisture control guides to ensure accuracy in blending the two – over a base
of concrete or tarmacadam to provide a uniform veneer to the surface. (Some contractors use
a honeycomb style plastic grating system to contain the aggregate.)
Failure to follow strict guide lines may result in ‘failures’ and ‘defects’ such as misting in the
finished surface, where white or lighter coloured areas appear in the resin due to atmospheric
or moisture conditions, or the surface begins to crumble due to incorrect batching/mixing.
Resin bonded is normally impermeable, and resin bound may be considered permeable,
provided that the base is also permeable. (See SuDS Regulations.) Resin bonded, when laid
over concrete (old or new) may be considered impermeable. Resin bound, especially when
laid over open grade 10mm tarmac (base coat tarmac) should be highly permeable, allowing
water to pass freely through the surface.
Both resin bonded and resin bound are prone to cracking unless their base is clean and sound.
They should not be treated as a cosmetic dressings to disguise old block paving (for example),
as it relies on the strength and integrity of the laying base for its success.
Skilled layers can create multi-coloured patterns and border edges to suit detailed designs,
with clean, crisp edges.
It should be considered a specialist service, as the tools and equipment – plus skills involved
– are not standard landscaping practices in most cases.
