Sandwich System Athletics Track: Layers and Advantages

The sandwich system is an impermeable athletics track surface combining an SBR rubber base mat with a poured polyurethane top layer. Its balance of performance and cost makes it the most widely used system for competition tracks.

The sandwich system gets its name from two different materials layered on top of each other: a rubber granule base that provides elasticity and a hard-wearing poured polyurethane top. This build-up lasts much longer than sprayed systems and costs less than a full PU system.

Layers of the sandwich system

• SBR base mat: SBR rubber granules are mixed with a polyurethane binder and laid in situ on the asphalt with a paving machine at about 9–10 mm. Most of the shock absorption comes from this layer.
• Pore filler: the porous surface of the base mat is sealed with a polyurethane paste. This stops the poured layer from soaking into the base and prevents bubbles.
• Poured polyurethane top layer: self-levelling two-component polyurethane is poured at about 3–4 mm.
• EPDM granule broadcast: coloured EPDM granules are broadcast into the wet polyurethane. Once cured, surplus granules are swept off, leaving a textured, slip-resistant surface suited to spikes.
• Line paint: lane and competition markings are applied with polyurethane line paint.

Total thickness is usually around 13 mm. Heavily loaded zones (high jump take-off, end of the javelin runway, steeplechase water jump exit) are built thicker.

Installation stages

Preparing the asphalt

Before work starts, the asphalt is checked with a 4 m straightedge, low spots are corrected and the surface is cleaned of dust and oil. The asphalt must be fully cured; otherwise volatiles can cause blisters in the surface.

Primer and base mat

A polyurethane primer is applied to the asphalt. The SBR base is then laid in continuous strips with a laser-controlled paver. Clean joints between strips are essential to avoid visible marks.

Pore filling and pouring

After the base has cured, the pore filler is squeegeed in. The polyurethane is then poured at an even thickness with a notched trowel or squeegee and EPDM is broadcast immediately. Temperature and humidity are monitored, and no pouring is done when rain is expected.

Curing and line marking

Once the surface has reached sufficient strength, surplus granules are removed, the track is surveyed and lines are painted.

Advantages of the sandwich system

• Impermeable: water runs off the surface into drainage channels; the base never becomes saturated.
• Long life: the poured polyurethane layer resists wear and spikes far better than sprayed surfaces.
• Certification: World Athletics-certified sandwich product systems can be used for Class 1 and Class 2 facility certificates with a correct base and survey.
• Cost balance: competition-level performance at a lower material cost than full PU.
• Renewable: a worn top layer can be renewed without touching the base.

Sandwich, full PU or spray coat?

Where budget comes first in schools and training grounds, spray coat is common; for national and regional competition tracks the sandwich system is the usual choice; and for stadiums hosting international championships with very heavy use, full PU stands out. For a detailed comparison read our athletics track surface systems comparison.

SFS Engineering installs sandwich systems on a turnkey basis together with groundworks, drainage and equipment as part of its athletics track construction projects.

Frequently Asked Questions

Is a sandwich system track permeable?

No. Because of the pore filler and the poured polyurethane layer, the sandwich system is impermeable. Rainwater is directed to drainage channels by the surface slope.

How thick is a sandwich system?

Usually around 13 mm in total: about 9–10 mm of SBR base and 3–4 mm of poured polyurethane with EPDM granules.

Can a sandwich track achieve World Athletics certification?

Yes. The product system must hold a World Athletics product certificate, and the facility must pass the survey and on-site tests.

Can the top layer be renewed?

Yes. The worn surface can be cleaned and covered with a new polyurethane and EPDM layer while the SBR base stays in place.

Get technical support for your project: SFS Engineering handles site survey, design, material selection and installation as a single contractor. Send us your dimensions and site details through our contact page and we will work out the right solution together.