A colour swatch is the least informative part of a coloured EPDM specification. The colour that actually reaches the court is decided by four things: how the pigment was introduced into the rubber, the binder ratio used at installation, the granule size and coating weight of the material, and whether a topcoat was applied over it. Two projects written against the same colour reference can end up as two visibly different surfaces, and the question that reaches the factory afterwards is rarely about pigment quality. It is about matching. This guide sets out what a colour specification has to fix so that the surface delivered in month six still resembles the panel approved in month one.
Key Takeaways
- Colour in a rubber sports surface is a system - pigment route, binder ratio, granule size, coating weight and any topcoat - and a colour reference alone cannot define it.
- There are three practical colour routes for EPDM granules: pigmented-through granules, colour-coated granules, and a separate coloured surface layer over an unbound or SBR base, and each one ages differently outdoors.
- UV and colour fastness should be quoted as a test method with a stated exposure and a stated limit, not as a verbal promise that the colour will hold.
- Batch continuity decides whether the second half of a project matches the first, which is why masterbatch records, lot numbers and retained samples belong in the order documentation.
- A defensible colour specification fixes the route, the reference and measurement method, the acceptance tolerance, the weathering evidence, the batch plan, and a cured site trial panel before bulk material is released.
Three Routes to a Coloured EPDM Surface
Colour in a rubber surfacing system is not one thing, and that is where a lot of specification language goes wrong. Granules arrive in at least three practical forms, and the route taken changes how the colour ages in sun, heat and traffic.
Pigmented-through granules are coloured in the compound before granulation, so the colour runs through the entire granule. Wear on the surface exposes the same colour underneath rather than a lighter interior, which makes the system visually forgiving on a playground or a path that sees heavy foot traffic. Colour-coated granules take their pigment at the surface after granulation, which allows a broad colour range from a smaller set of base compounds and keeps the colour layer thin, but it also means that a worn surface can expose the colour of the underlying granule. A coloured surface layer - often described as colour granules, or a coloured wear coat - places the pigment in a separate layer above an unbound or SBR base, which is the traditional way to build a two-tone or multi-colour sports court.
Each route has its own failure mode. Pigmented-through colour fades evenly as the whole granule weathers. Colour-coated colour can lose its surface layer first, leaving a shade difference between the trafficked zone and the edges. A coloured surface layer behaves like paint: it is the most visually precise option on day one and the most dependent on how it was mixed, cured and sealed. For a buyer, the useful question is not which route is best, but which route the supplier is actually able to deliver repeatably - because the difference between the two shows up on the second half of the project.
One material fact shapes this choice more than anything else. SBR granules made from recycled feedstock are permanently black: the colour is in the polymer itself and cannot be lightened. A coloured layer applied over a black SBR base is therefore a coating sitting on dark material, and under the abrasive load of studded footwear it tends to wear through and reveal black rubber underneath. That is why, in a two-layer system, the coloured wear layer is normally EPDM and the SBR sits underneath as the shock-absorbing base. If a quotation puts a coloured top layer over an SBR base on a surface that takes studded traffic, ask what the surface will look like once the high-traffic zones have worn through.
Why Two Orders of the Same Colour Do Not Match
Colour references are usually quoted as a shade, a code, or a photograph of a cured panel. None of those three carry the variables that decide the finished appearance. The list below is short enough to put in a specification.
Binder ratio is the first one, and the least understood. The proportion of polyurethane binder to rubber granules is set at the point of mixing, not at the factory. A richer binder ratio produces a deeper, glossier and slightly darker surface; a leaner ratio produces a drier, lighter and more textured one. The same granules and the same colour reference will therefore look different if two installers mix to different ratios - and the colour usually gets the blame.
The ratio is also not a free variable. Rough, torn or porous granules need less binder to lock together than smooth extruded granules, which need more in order to avoid raveling and de-bonding under the shear of footwear; typical practice runs roughly in the region of 12 to 15 per cent binder for rough recycled granules and 18 to 22 per cent for smooth EPDM granules. A mixed layer that sits below what the granule geometry requires does not only look drier, it starts to shed. A ratio written into the specification is therefore a structural decision as much as a colour one, and it protects the appearance as a side effect.
Granule size follows. A larger granule mesh gives a coarser surface that catches light differently, and the texture changes how a given pigment reads under the same illumination. Coating weight matters for the same reason: more pigment on the granule means a more saturated colour and a different wear profile. Base colour showing through is the third variable - a darker base under a thin colour layer shifts the result more than most people expect.
Then there are the site conditions. Cure and moisture state, ambient temperature during application, the number of passes, and whether a coloured topcoat was applied afterwards all change the final shade. A cured panel approved under controlled conditions is a useful reference, but it is a reference for one set of conditions, not a guarantee for every site.
What Actually Fades a Coloured Surface
Two different things get called fading, and they are fixed by different measures. Colour loss is chemistry: ultraviolet radiation breaks down the pigment and the surface of the polymer, and the surface becomes lighter, duller and eventually chalky. Surface wear is mechanics: the top layer is abraded away, the colour is not degraded but simply gone. A court that looks pale along the goal areas and in the centre circle has almost certainly been worn, and no pigment reformulation fixes it.
Ultraviolet degradation also depends on climate. A surface in a high-UV, high-temperature region sees a different exposure cycle from one in a temperate coastal zone, and the same formulation does not age identically in both. This is why exposure evidence from a test laboratory is worth more than a verbal claim: the laboratory method is repeatable, the claim is not.
Chalking is the version of fading that buyers most often misdiagnose. A rubber compound loaded with cheap inorganic filler can look sound when new, but ultraviolet radiation and abrasion slowly destroy the thin polymer matrix that holds the granule together, exposing the pale filler underneath. The surface then turns grey or white and starts shedding brittle particles. The colour is not the problem in that case; the surface chemistry is, and no pigment change will fix it. The same mechanism, combined with unbound process oil migrating and evaporating out of the rubber in summer heat - track surfaces regularly reach well above 60 degrees Celsius - produces a different failure: shrinkage, cracking along curbs, loss of shock absorption and a surface that hardens and embrittles rather than fades. Both failures are recorded in detail in our article on chalking, filler overload and oil trap.
The binder plays its own part in colour. Aromatic polyurethane binders photo-oxidise and yellow under sunlight, while aliphatic polyurethanes hold their colour stability. On a surface where the binder is visible - as it is in a wet-poured system or under a clear sealer - that difference shows up as a warm shift in the finished colour, and it shows up faster in a hot, high-ultraviolet climate.
Sealing with a pigmented or aliphatic polyurethane topcoat slows ultraviolet attack on the granules and restores the wet look of a fresh surface, but it also lays a film over the colour, which can deepen it or shift it slightly. If a topcoat is part of the system, the colour reference needs to state whether it applies before or after sealing, and ideally records the colour at both stages. This is a small clause that removes an entire category of dispute at handover.
UV and Colour Fastness: Ask for the Method, Not the Promise
Colour fastness data is only useful when it is specific. A supplier who states that granules are UV stable has given you a marketing sentence. A supplier who states the exposure method, the exposure duration, the substrate used, the colour-difference limit and the scale used for lightfastness has given you something you can put in a specification and verify. When requesting data, five items are worth asking for.
First, the exposure method: accelerated exposure under xenon arc or ultraviolet lamps following the ISO 4892 family of methods, with the hours of exposure stated - a 3,000-hour accelerated exposure programme is the common reference point for surfacing granules. Second, the limit: the colour-difference limit the material was tested to, and on what scale. Colour retention is normally expressed as a Delta E value in the CIELAB system, where a shift below 1.0 is generally treated as not perceptible, 1.0 to 2.0 as acceptable, and above 3.0 as an unacceptable shift. Third, the substrate: a test on loose granules tells you very little, because the finished surface has texture and a binder film that change how light is reflected. A cured panel at the intended mix ratio is the meaningful sample. Fourth, the pigment class behind the colour - organic pigments tend to fade faster under ultraviolet exposure, while inorganic metal-oxide pigments such as iron oxide for red or chromium oxide for green hold their shade better - and whether the formulation is genuinely lightfast or merely filtered. Fifth, and most practical, a panel taken from the actual production lot rather than from a laboratory sample, so that the panel on your desk is the material you are buying.
Two further references are worth requesting when the project is colour-critical. A grey-scale rating on the ISO 105 scale, where a result of grade 4 or better after accelerated exposure is the usual acceptance figure for surfacing granules. And the curing chemistry of the compound itself: sulfur-cured EPDM forms bonds that are less stable under heat and ultraviolet exposure, while peroxide-cured EPDM forms more stable bonds and generally resists ultraviolet and thermal ageing better. On a surface with a long service life in strong sun, that difference is a legitimate line on a specification.
Data from a production lot is also what makes a claim enforceable. It ties the number on the datasheet to the material in the container, which is exactly the link that is usually missing when a surface ages differently from the brochure. Our note on polymer content makes the same argument for material composition: a datasheet value is only meaningful when it describes the specific lot in the container.
Batching and Continuity: The Second Half of the Project
The most common colour complaint on a completed project is not that the colour was wrong. It is that the north half and the south half of the same court do not match. That happens when the material came from more than one production run, and it happens more often than buyers expect on projects split across several delivery windows.
Four documents or practices reduce it. Masterbatch records tie a colour reference to the pigment batch used to produce it, so that a repeat order is not a fresh pigment trial. Lot numbers on every bag make it possible to identify which material went into which area. A retained sample from each lot gives you a physical reference to settle a question months later, when the site surface has already been through a season. And a stated batch policy tells you what happens if a lot falls outside the agreed tolerance - whether the material is rejected, reworked, or accepted with a documented concession.
It is also worth asking how the colour is produced in the first place: whether a colour runs as a single production lot or as a blend of several lots to hit a target shade. Blending is normal industry practice and it is workable, but it has to be declared, because it changes what tolerance means and how a future repeat order should be handled. When the project includes matching an existing court, the reference should be an aged panel, not a fresh one, because a new surface and a three-year-old surface are never the same colour.
Comparing the Routes
The table below is the working comparison a buyer should request from any supplier of coloured granules. It is not a ranking - each route has a place - it is the set of questions that decide whether a route fits the site.
| Route | Where the colour sits | How it ages outdoors | Question to ask |
|---|---|---|---|
| Pigmented-through EPDM granules | Through the whole granule | Weathers evenly; worn areas expose the same colour | Is the colour introduced in the compound, and is the pigment class stated? |
| Colour-coated EPDM granules | On the granule surface | Colour layer can wear off before the granule does | What is the coating weight, and what does the granule look like beneath it? |
| Colour-coated SBR granules | On the granule surface, over a permanently black recycled base | Colour and surface wear move together on recycled feedstock | What is the recycled content and how is colour applied to it? |
| Coloured surface layer over an SBR base | A separate layer above a black base | Behaves like a coating: precise initially, dependent on mixing and cure | What is the layer thickness, and how is the base colour controlled? |
| Acrylic or PU court colour | In the coating film, not in rubber | A different system with its own colour specification practice | Is the colour part of the rubber system or a separate coating? |
Two practical notes for buyers comparing rubber routes. Coloured granules sold without a stated route are usually colour-coated, because that is the cheapest way to offer a wide palette - which is fine, as long as the specification says so. And any colour offer should be tied to a system, not to a bag: our EPDM colour granule range is normally specified together with a binder ratio and a topcoat decision, because those two choices are what turn a colour into a surface.
Writing a Defensible Colour Specification
1. Name the route and the product, not the colour
State which route the material uses, by product name and description, and state which surface system it is intended for. A colour name without a route cannot be compared between suppliers and cannot be re-ordered against a sample.
2. Fix the reference and the measurement method
Say what the reference is - a cured panel, a granule sample, a physical swatch - and how the comparison is to be made. Reference panels fade, so agree that they are stored and renewed, and record the instrument or method used for any measurement.
3. Agree the acceptance tolerance in advance
Set the permitted colour difference in the same units you will verify in, and write down what happens when a lot falls outside it. A tolerance that has no consequence attached is a formality.
4. Require the weathering evidence
Ask for the exposure method, duration, substrate and limit, and for a panel from the production lot rather than a laboratory sample. If the project is in a high-ultraviolet region, ask what the data covers for that exposure.
5. Plan the batch and the supply
Decide early whether the colour is bought in one production run, and require masterbatch records, lot numbers and a retained sample per lot. For projects with several phases, this is the clause that keeps the phases matched.
6. Approve a cured trial panel on site
A panel mixed at the specified ratio, cured under site conditions and reviewed before the bulk material is released. It is the cheapest way to catch a binder-ratio or colour-route problem while it is still a sample board rather than a finished court.
7. Record the topcoat decision
If the surface is sealed, record the colour reference before and after sealing, and name the topcoat. If it is not sealed, record that too - an unsealed surface has a different maintenance and appearance expectation, and it should be understood before handover rather than after.
Where Colour Specifications Fail on Site
Most colour disputes on completed projects come from the same short list of causes, and none of them is a pigment defect. A mixing ratio drifted from the specified value produces a shade difference between areas handled by different crews. Incomplete or uneven cure changes the surface appearance. Contamination of the base or of the mixing equipment shifts the result. Weather during application - high humidity, low temperature, or a squall mid-pour - affects the finish. Line-marking paint applied too early or over a surface that has not cured introduces its own colour shift at every line.
Two failures are organisational rather than technical. Comparing a fresh approved panel against a surface that has been in service for months is not a test, because both have changed. And changing the material route or the topcoat midway through a project, usually for convenience, produces two surfaces from one specification - which is exactly the outcome the specification exists to prevent.
The remedy is unglamorous and effective: one approved panel, one documented ratio, one material route, one topcoat decision, one batch plan, and a site trial before release. When the surface is handed over with those in place, the colour conversation that follows is usually not needed.
FAQ
Q1: What is the difference between coloured EPDM granules and colour-coated SBR granules?
The difference is both the material underneath and the way the colour is carried. EPDM granules use a synthetic, fully saturated polymer that stays flexible in cold conditions and resists ultraviolet ageing; SBR granules made from recycled feedstock are permanently black and more economical, which is why they are widely used as a base layer where a lower-cost base is acceptable. The practical question is not which is better, but where the colour is going: in a two-layer system the coloured wear layer is normally EPDM and the SBR sits underneath as the shock-absorbing base, because a coloured layer over black rubber tends to wear through to black under studded traffic. Binder ratio, topcoat and installation discipline all follow from that choice.
Q2: How do I specify a colour that will not fade on an outdoor sports surface?
Specify the route and the evidence, not the outcome. Name the colour route and product, request accelerated exposure data with the method, duration, substrate and colour-difference limit stated, ask for a panel from the production lot, agree an acceptance tolerance, and decide whether the surface is sealed. In a high-ultraviolet climate, ask what the weathering data covers for that exposure and for the colour in question. No specification removes the effect of sunlight, but it removes the argument about whether the material was fit for the exposure it was going to see.
Q3: How do I keep the colour consistent across a large project with several areas?
Buy the colour in a single production run where the schedule allows, require masterbatch records and lot numbers, and take a retained sample from each lot so that a later question can be settled against a physical reference. Agree the batch policy and the acceptance tolerance before the first delivery, specify the binder ratio and the number of application passes, and approve a cured trial panel on site before bulk release. Where phasing is unavoidable, the areas at the highest risk of mismatch are the ones separated by the longest gap in time, and those should be defined in the order rather than discovered on site.
Q4: Can coloured EPDM granules be used for both running tracks and sports courts?
Yes. The same granule family is used in the surface layers of running tracks, in playground surfacing and in multi-sport court systems. What changes between them is the system around the granules: binder ratio and layer build-up, the presence and type of topcoat, the line-marking specification, and the surface texture needed for the sport. A colour that works for a playground in a temperate climate may not be the right colour or the right route for a competition court in a high-ultraviolet region, and that is a system decision rather than a granule decision.
Planning a coloured surface and unsure which route and granule will hold up on your site? Tell us the surface type, the climate and the colour you need - we will recommend the granule, binder ratio and topcoat combination, with the batch documentation behind it, plainly.