Sika Sikaflex PRO-3
One-part polyurethane joint sealant built for industrial floors and civil works that has to take forklift wheels, chemical spills and constant movement.
What is it?
A one-component, moisture-curing polyurethane sealant for horizontal and vertical joints in floors and civil engineering structures.
Where is it used?
Warehouse and production floors, car park decks, pedestrian and traffic areas, food plants, cleanrooms, sewage works and tunnels.
Why use it?
It holds a watertight, elastic seal through +/-25% (ISO) to +/-35% (ASTM) joint movement while resisting chemicals and forklift loading.
How is it applied?
Gun-applied from a 300 ml cartridge or 600 ml foil pack into a primed, backing-rod-supported joint, then firmly tooled before skinning.
About Sika Sikaflex PRO-3
Sikaflex PRO-3 is Sika’s workhorse polyurethane sealant for the joints that get punished the most: floors and civil structures where the seal has to move with the slab, shrug off chemical contact and still survive wheel loading day after day. It cures on atmospheric moisture using Sika’s i-Cure technology, which gives a bubble-free skin even in thicker sections, and it firms up to a tough-elastic rubber that protects joint arrises from spalling instead of tearing under stress. In concrete grey, it blends into industrial slabs and stays over-paintable where a finished look is wanted.
For engineers and contractors, the appeal is that one product covers a wide envelope of duty. It is classed to ISO 11600 F 25 HM and ASTM C920 Class 35, carries CE marking to EN 15651-4 for pedestrian walkways, and holds documented resistance to diesel, jet fuel, waste water and a long list of cleaning chemicals. That combination lets a single specification run from a food-processing floor to a car park deck to a sewage treatment tank, which is why it is a common default on Indian projects where site conditions and exposures vary from bay to bay.
The technical insight
The performance comes from the polyurethane backbone curing into a high-modulus yet highly recoverable elastomer. Sikaflex PRO-3 stretches to roughly 600% elongation at break and returns about 90% elastic recovery, so after a joint opens and closes with thermal or structural movement the sealant springs back rather than sagging or permanently deforming. That elastic recovery is what keeps the seal watertight over years of cycling. Its higher-modulus character (Shore A around 37 after 28 days) is deliberate: unlike a soft, low-modulus facade sealant, PRO-3 is firm enough to carry shear from forklift and pedestrian traffic without extruding out of the joint or picking under wheels. The trade-off is that the joint has to be designed correctly for movement to be shared across the sealant width, which is why Sika fixes the width-to-depth ratio at 1:0.8 and insists on a closed-cell backing rod to control depth and prevent three-sided adhesion.
The number that quantifies that firmness is the tensile modulus: roughly 0.60 N/mm2 at 100% elongation. That stiffness is what lets the bead spread and shed a wheel load instead of deforming and being plucked out of the joint. It also explains the cure profile. Moisture-driven cross-linking runs from the surface inward at about 3.5 mm every 24 hours, so a skin forms in around 60 minutes and light foot traffic can usually return within a day, while the full section keeps curing for several days afterwards. Vehicle and forklift traffic must wait for that full-section cure – the surface skin is not a readiness signal – and deep joints must never be overfilled, which is the practical reason the backing rod is non-negotiable.
Where it is used
- Saw-cut and movement joints in warehouse, logistics and production floors
- Construction and expansion joints in car park and parking-deck slabs
- Pedestrian walkways and trafficked areas subject to foot and wheel loading
- Joints in food-industry floors and hygienic production areas
- Cleanroom floor and wall joints requiring low-emission, chemical-resistant sealing
- Sewage and waste-water treatment structures needing durable, water-resistant seals
- Tunnel and civil-engineering joints exposed to fuels and cleaning chemicals
- Interior and exterior horizontal and vertical joints in concrete elements
- Perimeter and isolation joints around plinths, machine bases and equipment foundations
- Saw-cut and isolation joints in cold-store and low-temperature slabs
- Terraces and trafficked exterior paving joints
- General building movement joints in masonry as well as concrete
Key advantages
- High movement capability of +/-25% (ISO 9047) and +/-35% (ASTM C719)
- Firm-elastic, high-modulus finish that carries forklift and traffic loads without extruding
- Excellent elastic recovery of around 90% for a durable, watertight seal
- Broad chemical resistance including diesel, jet fuel and waste-water exposure
- Bubble-free i-Cure curing gives a sound skin even in deeper joints
- Multiple third-party approvals: ISO 11600, ASTM C920, EN 15651-4 CE marking
- Very low emissions with GEV-Emicode EC1PLUS and LEED v4 credit potential
- Over-paintable and available ready-to-use in cartridge and foil-pack formats
- One-component and moisture-curing, so there is no site mixing and no ratio errors
- Bonds to concrete, cement screed, metal and most common construction substrates
Limitations & considerations
- Not a self-levelling grade for wide horizontal pours; joint width is limited to 10-40 mm
- Concrete grey is the standard colour and any wider range is limited and set by the local Sika organisation, so confirm shade availability before specifying
- Porous substrates such as concrete need Sika Primer-3 or Primer-210 for critical, high-stress or water-immersed joints
- Must not be used on bituminous substrates, EPDM, natural rubber or in and around swimming pools
- Uncured sealant must not contact alcohol-based products, which can disrupt curing
- Slower cure of about 3.5 mm per 24 hours means traffic must be kept off until the section has fully cured
- Not intended for permanent water immersion or hydrostatic joints without a dedicated waterproofing system
- Also unsuitable for natural stone prone to staining and for PE, PP and PTFE plastics
- Do not judge readiness from the surface skin: light foot traffic at about 24 hours, but vehicle and forklift traffic only once the full section has cured
Selection & best practice
Design the joint first: keep the width between 10 mm and 40 mm and hold a width-to-depth ratio of 1:0.8, inserting a closed-cell polyethylene backing rod to set depth and break the bond at the base so the sealant works in two-sided extension only. The substrate must be clean, dry and sound, free of laitance, oil and dust; use grit blasting or grinding where needed. On concrete and other porous surfaces, prime with Sika Primer-3 or Primer-210 for critical, highly stressed or water-exposed joints and observe the waiting time before sealing. Apply only when air and substrate are between +5 C and +40 C, with the substrate at least +3 C above dew point. Gun the sealant in with full contact to both joint faces, avoid air entrapment, then tool firmly against the sides within the roughly 60-minute skin time using Sika Tooling Agent N or clean water. Keep traffic off until the relevant depth has cured at about 3.5 mm per 24 hours.
Two site details decide whether the bead performs. First, preparation: curing compounds must come off along with laitance, dust and oil, or the sealant will bond to a weak surface layer rather than to the concrete itself. Second, tooling: compact the bead in a single firm pass so it wets both joint faces, rather than reworking a bead that has already begun to skin. Plan the traffic return around the cure and not the skin – light foot traffic after roughly 24 hours, vehicle and forklift traffic only once the section has cured, which takes several days and longer in cool or dry conditions. Store cartridges and foil packs in a cool, dry place and use them within the 15-month shelf life.
Specifications
| Chemical base | One-part polyurethane, i-Cure technology (moisture-curing) |
| Movement capability | +/-25% (ISO 9047); +/-35% (ASTM C719) |
| Shore A hardness | ~37 after 28 days (ISO 868) |
| Elastic recovery / elongation at break | ~90% recovery (ISO 7389); ~600% elongation (ISO 37) |
| Tensile modulus | ~0.60 N/mm2 at 100% elongation |
| Standards | ISO 11600 F 25 HM; ASTM C920 Class 35; EN 15651-4 PW EXT-INT CC 25 HM (CE); EN 14188-2 |
| Joint design | Width 10-40 mm; width-to-depth ratio 1:0.8 |
| Colour / density | Concrete grey; ~1.35 kg/L (ISO 1183-1) |
| Cure / working times | Curing ~3.5 mm/24 h; skin ~60 min; tooling ~50 min (+23 C, 50% r.h.) |
| Suitable substrates | Concrete, cement screed, metal and most common construction substrates |
| Traffic return | Light foot traffic ~24 h; vehicle and forklift traffic only after full-section cure (several days) |
| Packaging & shelf life | 300 ml cartridge (12/box), 600 ml foil pack (20/box); 15 months; service temp -40 C to +70 C |
Industry use cases
Warehousing & Logistics
Seals saw-cut and construction joints in high-throughput floors where forklift wheels would tear a softer sealant, protecting arrises from spalling.
Car Parks & Infrastructure
Handles expansion and movement joints in parking decks and traffic areas, staying watertight through thermal cycling and vehicle loading.
Food & Pharma Facilities
Low-emission, chemical-resistant sealing for food-industry floors and cleanrooms where hygiene and spill resistance matter.
Water & Waste Treatment
Durable joints in sewage and waste-water structures, with documented resistance to water, salt water and effluent exposure.
Tunnels & Civil Works
Flexible, fuel-resistant sealing of joints in tunnels and civil structures subject to movement and aggressive chemical contact.
Manufacturing & Heavy Industry
Construction and isolation joints in factory floors carrying point loads, thermal movement and occasional oil, fuel and hydraulic-fluid spillage.
Commercial & Institutional Buildings
General interior and exterior movement joints in concrete and masonry on offices, malls, hospitals and campuses.
Frequently asked questions
Can Sikaflex PRO-3 take forklift traffic?
Do I need a primer on concrete?
What joint width and depth should I use?
How much movement can the joint handle?
What pack sizes are available and how far does it go?
Can it be painted over?
When can traffic go back on the joint?
Can it be used for water-retaining or immersed joints?
How we position Sika Sikaflex PRO-3
Within the Sika range, Sikaflex PRO-3 is the go-to for trafficked floor and civil joints; where a joint needs chemical-resistant tank lining or crack bridging rather than sealing, pair it with Sikadur epoxy systems or Sikalastic membranes, and prime porous concrete with Sika Primer-3 or Primer-210 as the datasheet requires. Inside the Sika family, wide facade and cladding joints are better served by Sikaflex-11 FC or another low-modulus Sikaflex grade, sanitary and glazing joints call for a Sikasil silicone, and on heavy-duty slabs PRO-3 pairs naturally with the Sikafloor systems we also supply. For facade, glazing and perimeter joints that call for a softer, low-modulus movement seal rather than a floor grade, our Fosroc Nitoseal PU40 and hybrid MS-polymer options are the better fit, while Dr. Fixit and STP polyurethane sealants cover lighter general-purpose joints. Space Arc supplies and applies all of these as an authorised distributor across Delhi NCR and Pan-India, so a single project can standardise on one source for floor, facade and structural joint sealing.
Fosroc Nitoseal MS300 — Specify the Fosroc MS300 hybrid where a project wants a silyl-modified polyether that is trafficable like PRO-3 but primerless on most substrates and lower in odour for enclosed food or pharma floors.
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Source Sika Sikaflex PRO-3 for your project
Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.