Sika Sikagard PU UR
A two-component, non-yellowing polyurethane finishing coat that seals and protects concrete and steel structures against UV, saline air and weathering in a glossy RAL-shade finish.
What is it?
A two-component, solvent-borne polyurethane protective and sealer topcoat for concrete and steel, colour-stable and glossy in various RAL shades.
Where is it used?
Cooling towers, coastal bridges and flyovers, chimneys, effluent and wastewater plants, chemical facilities and exposed metal structures in marine locations.
Why use it?
Delivers a UV-stable, non-yellowing, low-dirt-pickup finish that resists saline atmospheres and mild chemical attack while keeping structures looking clean.
How is it applied?
Mixed Part A:B at 7:1 by weight and applied by roller or brush in two coats over a primed, dry substrate at roughly 0.15 kg/m² per coat.
About Sika Sikagard PU UR
Sikagard PU UR is the finishing layer in a Sika protective system rather than a stand-alone paint. It is a two-component polyurethane coating supplied as pre-batched Part A and Part B units that you combine on site to form a tough, glossy film. Its job is to sit on top of a prepared and primed concrete or steel surface and act as the weather-facing barrier, the layer that takes the UV, the salt spray and the grime while the substrate stays sound underneath. For consultants working on assets in Delhi NCR and along India’s coastline, that combination of colour stability and corrosion resistance is what makes it a specification choice for structures that have to look presentable for years, not just months.
Where an ordinary alkyd or epoxy topcoat would chalk, yellow or fade under sunlight, this polyurethane holds its colour and gloss. Sika rates it as showing no discolouration under UV exposure and no chalking, checking, flaking or corrosion after 1440 hours of artificial weathering to DIN EN ISO 11507. It is offered in a range of RAL shades, so it doubles as a decorative finish on facades and exposed steelwork while doing the real work of shielding the concrete or metal below. It is deliberately a mild-to-moderate exposure product, tuned for saline and weathering duty rather than aggressive chemical immersion, and that honest positioning is worth keeping in mind when you match it to a project.
The technical insight
The performance comes from the aliphatic-style polyurethane chemistry of the cured film. When Part A (the pigmented resin) and Part B (the transparent hardener) are mixed 7:1 by weight, the two components crosslink into a dense, tightly bonded network. That crosslink density is what gives the film its hardness, its gloss retention and its resistance to breaking down under ultraviolet light, so unlike aromatic or general-purpose coatings it stays colour-stable and non-yellowing outdoors. The same tight film is what keeps saline moisture and airborne chlorides from reaching the concrete or steel beneath, which is why it is trusted in marine and coastal exposure. Because it is a reactive two-part system, the clock starts once the parts meet: pot life is about 30 minutes at +30 degrees C, so only mix what a crew can lay down in that window. It cures touch-dry in roughly 24 hours and reaches full cure in about 7 days, at which point the protective barrier is complete.
Where it is used
- Protective and sealer topcoat on RCC cooling towers exposed to constant moisture and drift
- UV-stable finishing coat on bridges and flyovers in coastal and marine locations
- Anti-corrosive topcoat over primed steel and metal structures in saline coastal zones
- Weather-facing coat on chimneys and tall exposed concrete elements
- Protective finish inside and around wastewater and effluent treatment plants
- Topcoat on concrete and steelwork at chemical manufacturing facilities with mild chemical exposure
- Decorative, colour-stable coating on commercial facades and rendered surfaces
- Protective coating over asbestos cement, stone and rendered substrates against aggressive atmosphere
Key advantages
- UV resistant, colour stable and non-yellowing, so the finish holds its appearance outdoors
- Resistant to saline environments, making it suited to coastal and marine structures
- Good chemical resistance against mild and moderate atmospheric exposure
- Glossy finish available in a range of RAL shades for a decorative as well as protective role
- Low dirt pick-up keeps coated surfaces looking clean between maintenance cycles
- Bonds to a wide range of substrates including concrete, render, stone, asbestos cement, steel and iron
- Strong adhesion of at least 1.5 N/mm2 on concrete substrate to ISO 4624
- Applied simply by roller or brush, so no specialist spray equipment is essential
Limitations & considerations
- Not suitable for highly acidic environments; strong acids can cause discolouration and reduce durability, where Sikagard-63 is the correct choice
- Not designed for areas of high abrasion or mechanical wear
- On damp concrete or where moisture ingress is likely, a Sikagard-720 Epocem IN moisture barrier is needed first
- Requires a properly prepared, primed and dry substrate; water cleaning of the surface is not permitted before application
- Short pot life of about 30 minutes at +30 degrees C means material must be mixed in small, workable batches
- Application is restricted to +10 to +40 degrees C, up to 70% relative humidity, with substrate moisture at or below 4%
Selection & best practice
Treat Sikagard PU UR as the last coat in a system, never in isolation. On concrete, get the surface dry and free of dust and laitance, roughen it with sandpaper or a wire brush, and use a pore-filling epoxy putty such as Sikadur PF IN for a good-quality finish; where moisture is a risk, apply Sikagard-720 Epocem IN as a moisture barrier first, followed by the recommended primer. On steel, remove all rust and old coatings, roughen and clean the surface, treat corroded metal with Sika Rustoff-100 and protect it with Friazinc R before coating. Mix Part A and Part B for three minutes with a low-speed stirrer at 250 to 300 rpm until homogeneous but without whipping in air bubbles. Check that the substrate sits at least 3 degrees C above the dew point to avoid condensation, then apply by roller or brush in two coats to reach around 150 microns total, allowing about 6 hours between coats. Clean tools with Sika Colma Cleaner immediately after use, since cured material can only be removed mechanically.
Specifications
| Chemical base | Two-component polyurethane resin |
| Mixing ratio | Part A : Part B = 7 : 1 by weight |
| Density (mixed) | 1.20 ± 0.05 kg/L at +30 °C |
| Solid content by weight | ~68% |
| Consumption | ~0.15 kg/m² per coat (substrate-dependent) |
| Layer thickness | ~150 microns in 2 coats |
| Tensile adhesion strength | ≥ 1.5 N/mm² on concrete (ISO 4624) |
| Pot life | ~30 minutes at +30 °C |
| Drying time | Touch dry ~24 hours; full cure ~7 days |
| Packaging | 4 kg pre-batched sets (Part A 3.50 kg + Part B 0.50 kg) |
| Shelf life | 12 months from date of production |
Industry use cases
Coastal & Marine Infrastructure
Specified as the UV-stable, salt-resistant topcoat on bridges, flyovers and exposed steel in coastal zones where chloride-laden air would otherwise drive corrosion.
Power & Cooling
Applied to RCC cooling towers and chimneys that face continuous moisture, drift and sunlight, keeping the concrete sealed and colour-stable over long service life.
Water & Wastewater
Used as a protective finish around effluent and wastewater treatment plants where structures need weather and mild-chemical protection without heavy abrasion duty.
Chemical & Process Plants
Chosen as the finishing coat on concrete and steelwork in mild chemical atmospheres, with Sikagard-63 reserved for the genuinely aggressive acidic areas.
Commercial Facades
Doubles as a decorative RAL-shade finish on facades and rendered surfaces, combining a clean glossy look with low dirt pick-up and anti-carbonation-grade protection.
Frequently asked questions
Is Sikagard PU UR the same as Sikagard PU UR (W)?
How much Sikagard PU UR do I need per square metre?
Can I apply it directly onto bare concrete or steel?
Will it resist chemical attack in an industrial plant?
What is the pot life and how long before it is usable?
Does the colour fade or yellow outdoors?
How we position Sika Sikagard PU UR
Sikagard PU UR is best understood as the topcoat in a full Sika protective build-up, not a one-tin solution. On concrete it typically follows Sikagard-720 Epocem IN as a moisture barrier and a primer such as Sikadur PF IN, Sikagard-67 or Sikafloor-161 HC; on steel it sits over Friazinc R or Sikafloor-161 HC after rust removal with Sika Rustoff-100. When the exposure turns genuinely acidic or aggressive, step up to Sikagard-63 instead of pushing this product beyond its mild-chemical remit. For lower-cost decorative anti-carbonation duty on concrete you might instead look at the waterborne Sikagard PU UR (W). Across our other brands, Space Arc can offer Fosroc’s Dekguard family and Dr. Fixit protective coatings as alternatives where a client’s approved-vendor list or crack-bridging requirement points that way, and we will match the coating honestly to the substrate and exposure rather than to a single label.
Fosroc Dekguard E2000 — A specifier may prefer Dekguard E2000 when the priority is a water-based, crack-bridging, breathable anti-carbonation coating on concrete, whereas Sikagard PU UR wins where a harder, higher-gloss, UV-stable polyurethane finish is needed on both concrete and steel.
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