If you’re planning to install a resin bound driveway, patio or pathway, one of the first questions you’ll ask is: What exactly is included in a resin bound kit?

While the exact contents can vary depending on the aggregate blend and manufacturer, most professional resin bound kits contain carefully measured components designed to produce the correct strength, appearance and workability. Using the correct ratios is essential for achieving a durable, long-lasting surface.

Decorative Aggregates

The largest component of any resin bound kit is the decorative aggregate, typically around 100kg per standard mix.

These natural stones are washed, graded and kiln-dried before packaging to ensure they are completely dry and ready to mix. Moisture within the aggregate can interfere with the polyurethane resin, leading to clouding, poor bonding and reduced strength.

Most resin bound blends use a carefully selected combination of aggregate sizes, commonly:

• 1–3mm decorative stone
• 2–5mm decorative stone

The combination of different sizes helps create a dense, attractive surface with excellent strength and minimal voids.

Because the aggregates are natural stone rather than dyed, the colours remain stable and retain their appearance for many years.

Kiln-Dried Sand or Binding Quartz

Depending on the colour blend and mix design, many resin bound kits also include kiln-dried sand or a specially selected binding quartz.

These fine materials help improve the packing density of the mix by filling the spaces between the larger aggregates. This creates a stronger, smoother and more consistent finished surface while helping to optimise resin distribution.

Not every blend requires sand or binding quartz. The exact formulation depends on the aggregate grading and the desired appearance of the finished surface.

Two-Part Polyurethane Resin

Every resin bound kit also includes a two-part UV-stable polyurethane resin system, consisting of:

• Part A – Polyol
• Part B – Isocyanate

These two components are mixed together immediately before installation. Once combined, the resin begins to cure, binding every individual stone together to create the strong, seamless surface associated with resin bound paving.

Professional resin systems are carefully formulated to provide:

• Excellent UV stability
• High bond strength
• Flexibility
• Long-term durability
• Consistent curing

What About the Catalyst?

One component that is often misunderstood is the catalyst.

The catalyst controls how quickly the polyurethane resin cures and is used to adjust the working time to suit different weather conditions.

During colder weather, a catalyst is commonly added to accelerate curing and ensure the surface hardens within the desired timeframe.

In hot summer conditions, however, many professional installers prefer to use an uncatalysed resin. Instead of having the catalyst pre-added at the factory, it is supplied separately and added on site immediately before mixing.

This gives experienced installers complete control over curing times, allowing them to adjust the amount of catalyst according to:

• Air temperature
• Ground temperature
• Humidity
• Surface size
• Number of installers
• Mixing speed

Having this flexibility is particularly valuable on larger projects, where consistent working time across multiple batches is essential to achieving a seamless finish.

Why Correct Ratios Matter

Every component within a resin bound kit has been carefully calculated to work together.

Adding too much or too little resin, changing the aggregate ratio or altering the sand content can affect:

• Surface strength
• Permeability
• Appearance
• Slip resistance
• Long-term durability

For this reason, professional installers should always follow the manufacturer’s recommended mix design unless using a specially engineered formulation.

Professional Resin Bound Kits from Advanced Resin Supplies

At Advanced Resin Supplies, every resin bound kit is developed using both real-world installation experience and laboratory testing. Our carefully selected decorative aggregates, premium UV-stable polyurethane resin and professionally balanced mix designs have been refined through years of practical installations across domestic and commercial projects.

Whether you’re completing a small DIY pathway or supplying materials for a large commercial development, we offer complete resin bound kits, technical guidance and expert support to help ensure every installation is successful.

If you’re unsure which resin bound kit is right for your project, our team can advise on colour selection, coverage, resin choice and curing systems to suit the time of year and installation conditions.