PU Backing vs SBR Latex: What You Are Actually Paying For
Two tenders land on your desk in the same week. Both quote 50 mm monofilament at 12,000 Dtex and roughly 10,000 stitches per square metre. One of them is 32% cheaper per square metre, and the yarn is rarely where that gap comes from. The backing is.
Backing is the least photographed part of a football pitch, and nobody puts it in the brochure. Yet it decides most of what goes wrong later. Tufts come loose, seams open after the first wet season, and a rubber smell lingers in an indoor hall for a fortnight after handover.
This guide compares the two secondary coatings you will be offered. It covers which projects should pay the premium, which should not, and what to demand on the quotation so that the comparison is real.
Quick answers
| Question | Short answer |
|---|---|
| What is a secondary coating | The compound applied to the back of the carpet to lock the tufts |
| Which locks tufts better | PU, typically 40 to 50 N against 25 to 35 N for latex |
| Which handles water better | PU does not absorb water. Latex film picks up moisture and softens |
| Is PU always the right choice | No. Dry climates with an 8-year cycle rarely justify it |
| Can a 30 N tuft bind pass as 45 N | No. Ask for the report and the laboratory name |
| Does PU make the pitch feel harder | No. Feel comes from pile, infill and shock pad |
The three layers people call "the backing"
The word backing covers two different parts, and suppliers blur them when it suits the price.
The primary backing is the cloth the yarn is tufted into. Polypropylene is standard, while composite cloth with a fleece layer is used where dimensional stability matters more.
The secondary coating goes on the reverse side after tufting. It penetrates the stitch holes and cures, and it is the only thing holding each tuft in place. SBR latex and PU are the two options here.
The finish adds drainage holes, a stated coating weight, and sometimes a laminated fleece.
So "PU backing" does two jobs in this market. It can mean a PU precoat on standard polypropylene cloth, or a PU-impregnated system where the whole back assembly is different. Those are different products at different prices, which is why question one on any quotation should be which one this is.
Five ways the two coatings differ
1. Tuft lock, and what shedding really means
Tuft withdrawal force is measured by pulling one tuft out of the backing to ISO 4919, and the result is given in newtons. It is the closest thing to a durability guarantee that a carpet carries.
The industry benchmark for sports turf sits near 30 N. Our UNI-PRIME SM50 is specified at 45 N or more under ISO 4919 with PU coating, and that gap is not cosmetic. It decides whether a pitch still holds fibre at the goalmouth in year four.
Shedding shows up first at the penalty spot, the goal area and the seam lines rather than the centre circle. Cleats rotate hardest wherever players plant and turn, and every rotation load is carried by the bond between tuft and backing. A latex carpet at 30 N is fine on a training ground that sees 15 hours a week. On a rental hub running 70 hours a week, the same bond does four times the work.
What to ask: state the tuft withdrawal force in newtons, the standard used, and the laboratory that issued the report.
2. Water, absorption and drainage
Most of the market gets this wrong in both directions.
SBR latex is a water-based dispersion that cures into a flexible film, and that film still takes up moisture. Over a wet season the coating gains weight, softens slightly and loses some of its grip on the tuft base. The change is slow, and you see it as seams that creep, edges that lift, and a carpet that needs re-stretching.
PU does not absorb water because it is a closed, cohesive film. That is why PU rolls stay dimensionally stable through a monsoon, and why covered and indoor pitches default to PU.
Here is where the marketing overreaches. PU backing does not make a pitch waterproof, because water still has to leave the surface. It leaves through the pre-punched holes in the coating, not through the coating itself. SM50 is specified at 65 L/min/m² or better, so ask for the measured figure and the build it was measured on.
What to ask: what is the water permeability in L/min/m², and does the coating use pre-punched holes or a high-flow pattern? A PU carpet with blocked holes ponds just like a latex one.
3. Freeze-thaw, and why latex cracks
This failure is mechanical rather than chemical. Moisture held in the latex film freezes and expands by about 9%, pushing against a film that has already stiffened in the cold. Repeat that forty or fifty times across a winter, and hairline cracks open along the fold lines and seam edges. Once the coating cracks, the tuft base is exposed.
That is why one latex product can last fifteen years in a mild coastal climate and four years in a continental one. Climate comes first, and product quality second.
PU flexes at low temperature without cracking, but it carries its own risk in hydrolysis, which I cover below.
What to ask: has the coating been freeze-thaw cycled, how many cycles, over what temperature range, and what happened to tuft withdrawal afterwards? That last part matters most, because anyone can survive one cycle.
4. Odour, VOCs and indoor pitches
SBR latex compounds carry antioxidants and cure residues, and they can release an ammonia-type odour while they finish curing. Outdoors with wind and rain, nobody notices. In a covered hall or a cage with a roof and four walls, it becomes the first complaint the operator hears.
PU dispersions leave fewer residual volatiles, which does not make every PU product odour-free and does not replace an emissions test.
What to ask: which VOC or emissions test ran on the finished carpet, and can I see the report? For indoor and school work, the certificate pack should include RoHS, REACH SVHC and a fire test, and ours runs to ISO 9239-1.
5. Weight, roll format and the freight line
A PU coating is applied at a lower weight than latex for the same tuft lock, so the finished roll is lighter. Lighter rolls put more square metres into a 40ft container, unload with less labour and crease less in transit.
That is a real cost offset, and it is the argument a PU supplier should be making. It is also where a bad quotation hides, because cutting coating weight improves the container maths and the saving returns later as poor stability in heat.
What to ask: what is the coating weight in g/m², the roll weight, and the m² per 40HQ at this specification? Get all three together, or none of them mean anything.
| Failure mode | SBR latex | PU | Test to demand |
|---|---|---|---|
| Tuft shedding | 25 to 35 N typical | 40 to 50 N typical | ISO 4919 |
| Water uptake | Absorbs, softens slowly | Does not absorb | Coating weight and immersion check |
| Freeze-thaw | Cracks at folds and seams | Flexes without cracking | Cycle count and post-test tuft bind |
| Odour indoors | Cure residues | Fewer residual volatiles | VOC report |
| Roll weight | Heavier at equal tuft lock | Lighter, more m² per 40HQ | Coating g/m² and m² per 40HQ |
| Main risk | Climate degradation | Hydrolysis if the grade is wrong | PU type and stabiliser statement |
The one risk PU buyers miss: hydrolysis
PU is not automatically the better engineering choice, because polyester-based PU can hydrolyse in hot and humid conditions. The polymer chain breaks at the ester linkage, and the film goes tacky, then chalky, then powdery. Malaysia, the Gulf, coastal West Africa and any unventilated indoor hall are exactly where this appears.
Polyether-based PU resists it, and so does polyester PU with hydrolysis stabilisers. The distinction is invisible in a sample book and invisible in a price.
What to ask: is the PU polyether-based or polyester-based, is a hydrolysis stabiliser included, and what hot-humid ageing data exists? A supplier who cannot answer has not tested it.
When SBR latex is the right answer
There are three cases, and they are more common than the sales material admits.
Dry, mild climates with a set replacement cycle are the first. If there is no hard freeze and the owner plans to resurface at year eight, the extra life from PU is not recoverable.
Community and school pitches under 25 hours a week are the second, because tuft lock matters in proportion to traffic. Below that threshold, a 30 N latex carpet with good infill maintenance performs to expectation.
A tight capital budget with strong maintenance capacity is the third. A latex pitch that gets brushed weekly and topped up in year two outlasts a PU pitch that gets neither.
Our UNI-EC01 economy turf is built for the second case. If budget is the real constraint, the cheap versus economy checks are a more useful read than a backing upgrade.
When PU earns its premium
Four conditions point to PU, and any two of them usually justify the step up.
A hard freeze or a heavy monsoon comes first, because these are the two conditions where latex degrades fastest and the mechanism is well understood rather than speculative. Covered and indoor pitches follow for the same reason on odour and moisture. High-hour rental hubs above about 50 hours a week come third, since the tuft bond becomes the limiting part at that traffic level, and that is where a 45 N specification pays for itself. The cage court guide covers the traffic side of the same problem.
The fourth is a tender that requires a tested system. If the specification names FIFA Quality or Quality Pro, the whole build is tested together, meaning carpet, infill and shock pad. A certificate is issued against a build rather than a roll, so check that the coating in your quote matches the coating in the tested system.
Six numbers that settle the comparison
Put these in the same email to every supplier, and the answers will sort themselves out.
1. Tuft withdrawal force in newtons, plus the standard and the laboratory
2. Secondary coating type and weight in g/m², and whether the PU is polyether or polyester based
3. Water permeability in L/min/m², with the drainage pattern described
4. Freeze-thaw or hot-humid ageing result, including tuft bind after the test
5. Roll weight and m² per 40HQ at the quoted specification
6. Certificate number, and the build it covers
A quotation that answers all six is comparable. One that answers three is a price rather than an offer.
Comparing the two prices properly
Do not compare price per square metre, because that number hides the two costs that decide the outcome. Compare cost per square metre per year, and put the container maths in the same line.
The template is short enough to run on one sheet. Landed cost is ex-works plus freight, insurance and unloading, divided by the area actually installed, using gross rather than net area. Installed cost adds infill, shock pad where specified, jointing and labour. Annual cost divides installed cost by expected service life, and the last line adds one seam repair or one re-stretch where the coating makes either likely.
Run your own numbers into it, and the gap between two quotes usually narrows from 32% to under 15%. Occasionally it reverses, because a heavy latex roll that costs more to ship and creases in transit can lose its price advantage before the first match.
Installation differences worth knowing
PU rolls behave differently on site, and the installation team should know this before the delivery date.
PU moves less with temperature, so rolls can be laid closer to final position on the first pass and a re-stretch on large pitches is often unnecessary. Adhesive compatibility needs checking, because not every turf adhesive bonds well to PU. Seam preparation matters more than usual, since PU is smoother and less porous than latex and a ragged cut edge shows as a visible line. Curing is less moisture sensitive than a latex system, which helps in humid weather without removing the need to keep the seam dry. Lighter rolls also handle better on rooftops and in lifts, which matters more than it sounds on urban sites.
Base preparation and sequence are covered in the installation guide, and the full parameter set for a competitive pitch is in the football turf specification guide.
Specification for a professional pitch
| Parameter | Target | Note |
|---|---|---|
| Pile height | 50 to 60 mm | 50 mm for most competitive pitches |
| Yarn | Stem or diamond monofilament, virgin PE | Ribbed edge resists splitting |
| Yarn count | 12,000 to 14,000 Dtex | Below 10,000 fibrillates under adult play |
| Gauge and stitch | 5/8 inch, 10,000 stitches/m² or more | Density means little without dtex |
| Primary backing | Composite cloth | Woven PP is fine at lower traffic |
| Secondary coating | PU, with stated weight in g/m² | Confirm polyether or stabilised polyester |
| Tuft withdrawal | 45 N or more to ISO 4919 | With laboratory report |
| Water permeability | 60 L/min/m² or more | With pre-punched drainage |
| System performance | Tested to EN 15330-1 | Shock absorption, deformation, ball behaviour |
| Shock absorption | 55 to 70% | System property, and it needs a pad on concrete |
| Certification | FIFA Quality or Quality Pro where required | Covers the build rather than the roll |
| Design life | 10 to 12 years | With infill top-up and annual brushing |
Fibre shape sits one level above this table, and the diamond versus flat fibre comparison covers it. For a training venue rather than a competition venue, UNI-MAXPRO sits at the right point on the curve.
FAQ
1. Is PU backing better than SBR latex?
For tuft lock, water resistance and freeze-thaw behaviour, yes. For cost per square metre, no. The real question is whether climate, traffic and replacement cycle let the extra cost come back. It usually does on a covered pitch in a freezing climate, and usually does not on a dry-climate school field resurfaced at year eight.
2. Does PU backing make a pitch waterproof?
No. PU does not absorb water, but water still leaves the surface through the pre-punched holes, so a PU carpet with a poor drainage pattern ponds like a latex one. Ask for the measured permeability.
3. Can I tell PU from latex by looking at the roll?
Not reliably, since both are dark coatings on the reverse face. PU is usually smoother, slightly glossier and lighter for the same tuft lock, but the only defensible check is coating weight plus a test report.
4. Will PU backing change how the pitch plays?
No. Backing sits under the carpet, and ball roll, firmness and shock absorption come from pile height, infill, fibre shape and the shock pad. A supplier who says a backing upgrade changes playing feel is selling the wrong variable.
5. How long does a PU-backed pitch last?
Ten to twelve years on a maintained competitive pitch is a normal design life, and that is the figure we specify for UNI-PRIME SM50. Infill top-up and annual brushing decide whether it reaches the top of that range, and backing buys the years that climate would otherwise take.
What is the minimum order?
Our minimum order is 500 m², and production lead time is about 30 days for standard specifications.
Choosing between the two
The decision is not which coating is better. It is which failure mode your site will actually deliver, and whether the price gap survives it.
Send us the climate zone, the weekly hours, the base type and whether the pitch is covered, and we will tell you which coating the site justifies. Sometimes the answer is the cheaper one.
