Sika Sikaflex® Construction+
A one-component polyurethane facade and floor-joint sealant engineered for ±35% movement, built to take Delhi NCR’s 45°C summers and near-zero winter mornings in stride.
What is it?
A one-component, moisture-curing polyurethane sealant (Sika’s i-Cure® Technology) for movement and connection joints in facades, precast panels and rigid floor joints.
Where is it used?
Precast/GFRC facade panels, curtain walling, cladding and infill joints, window and door perimeters, and floor joints in warehouse aprons, highways and airport pavements.
Why use it?
It absorbs ±25% to ±35% joint movement without losing adhesion, cures bubble-free even in monsoon humidity, and carries EN 15651-1, ISO 11600-F, ASTM C920 Class 35 and BS 5212 approvals for spec-driven work.
How is it applied?
Gunned from a 600 ml foil pack into a backer-rod-fitted joint, primed where the substrate calls for it, then tooled within roughly 55 minutes before it skins over.
About Sika Sikaflex® Construction+
Sikaflex® Construction+ is the general-purpose workhorse of Sika’s Sikaflex range — a one-component, i-Cure® Technology polyurethane that cures by reacting with atmospheric moisture rather than by mixing two parts. That single-component simplicity is why it turns up so often on Delhi NCR and Pan-India facade work: an applicator loads a 600 ml foil sausage into a standard gun, tools the bead within about 55 minutes, and moves on, without a pot-life clock running in 40°C site heat.
What earns it a place on precast, curtain-wall and rigid-pavement specifications is the movement figure — ±25% under ISO 9047, ±35% under ASTM C719 — enough elastic give to absorb the daily and seasonal expansion-contraction cycle a north-Indian facade actually sees, from a scorching afternoon to a foggy January morning, without tearing at the bond line. Space Arc Engineering, as an authorised Sika distributor and applicator across Delhi NCR, supplies it ex-stock and also handles the priming, backer-rod work and tooling the datasheet calls for on critical or multi-storey jobs — the details that usually decide whether a joint lasts five years or fifteen.
The technical insight
The engineering behind Sikaflex Construction+ is its low-modulus curve — secant tensile modulus of only ~0.45 N/mm² at 100% elongation at +23°C — so it resists joint movement gently rather than fighting it, protecting adhesion through repeated cycling. Elongation at break of ~800% and elastic recovery of ~90% give a wide safety margin. That chemistry only pays off if the joint is sized correctly: Sika’s tables (to DIN 18540 for the ISO figure, ASTM C1472 for the ASTM figure) set joint width against panel spacing — a 6 m joint spacing calls for roughly 15-20 mm width, 10 mm depth — with a mandatory 2:1 width-to-depth ratio and a closed-cell backing rod so the bead bonds only to the two joint faces, not the base. Three-sided adhesion from a missing backer rod is the single most common cause of premature sealant tearing seen on Indian sites.
Where it is used
- Movement joints between precast concrete and GFRC facade panels
- Perimeter sealing of curtain walling, cladding and infill panels
- Connection joints around window and door frames
- Floor joints in warehouse aprons, highway slabs and airport pavements
- Joints between porous (concrete, brick, render) and non-porous (aluminium, glazed tile) substrates
- Interior connection and crack-control joints in dry areas
- Joint sealing on pre-cast / tilt-up elements during erection
- Weather-exposed vertical and horizontal building-envelope joints
Key advantages
- Wide movement range (±25% to ±35%) suited to Delhi NCR’s extreme thermal swing
- i-Cure® Technology cures bubble-free even in monsoon humidity
- Broad service range, -40°C to +70°C once cured
- Adheres to most substrates largely without primer, cutting site labour
- Can be over-painted with tested, compatible facade coatings after full cure
- EMICODE EC1 Plus R rated — very low emissions for LEED-documented projects
- Multi-standard compliance (EN, ISO, ASTM, BS) supports spec sign-off
- 600 ml foil-pack format fits standard guns, less wastage on long joint runs
Limitations & considerations
- Not for natural stone, bituminous substrates, natural rubber or EPDM
- Not rated for swimming pools or permanent water immersion
- Uncured sealant must avoid alcohol-based products, which disrupt curing
- Minimum 6 mm joint width with a fixed 2:1 width:depth ratio — no fix for an undersized joint
- Over-painting needs full cure first (~3 mm/24 hr); painting early risks film cracking
- Colour range limited to local Sika sales stock, not an open palette
Selection & best practice
Size the joint from Sika’s width/depth tables against actual panel spacing before ordering — never seal under 6 mm or outside the 2:1 ratio. Fit a closed-cell backing rod first so the bead only bonds the two joint faces. Prime porous substrates with Sika Primer-3N, metals and glazed tile with Sika Aktivator-205, and PVC with Sika Primer-215 — skipping primer on a stressed or high-rise joint is the most common cause of early adhesion failure. Tool firmly within the ~55-minute window with a solvent-free tooling agent, and if the joint will be painted, wait for full cure and pre-test the paint system rather than assuming compatibility.
Specifications
| Chemical base | i-Cure® Technology polyurethane |
| Density | ~1.45 kg/L (ISO 1183-1) |
| Movement capability | ±25% (ISO 9047) / ±35% (ASTM C719) |
| Shore A hardness | ~28 after 28 days (ISO 868) |
| Elongation at break | ~800% (ISO 37) |
| Service temperature | -40°C to +70°C |
| Standards | EN 15651-1 F-EXT-INT-CC 25HM, ISO 11600-F, ASTM C920 Class 35, BS 5212 Part 1:1990 |
| Pack size | 600 ml foil pack, 20 packs/box |
| Skin time / tooling time | ~65 min / ~55 min (23°C, 50% RH) |
Industry use cases
Commercial facades
Movement joints between precast/GFRC cladding on Gurugram and Noida office towers, where south/west panels see the widest daily swing
Airports & highways
Rigid-pavement expansion joints in taxiways, aprons and highway slabs, where ASTM C920 Class 35 is often specified
Residential high-rises
Perimeter sealing around window and door frames in curtain-wall or masonry facades
Industrial & warehousing
Floor joints in warehouse aprons and infill-panel joints on pre-engineered building envelopes
Institutional / government
Low-VOC, multi-standard sealant for LEED-documented or code-mandated public buildings
Frequently asked questions
Can it be painted over?
Does the joint need a primer first?
Can I use it for a swimming pool or water-tank joint?
How much joint length does one 600 ml pack cover?
What’s the shelf life, and how should we store it on site?
How does this differ from other Sikaflex sealants Space Arc stocks?
How we position Sika Sikaflex® Construction+
Within Space Arc’s Sika range, Construction+ is the default for facade and rigid-pavement movement joints; Sikaflex-11 FC+ suits faster-tooling interior work, Sikaflex PRO-3 is built for trafficked floor and road joints, and Sika Primer-3N / Aktivator-205 complete the priming system. Where the job is mainly facade or window-perimeter sealing on a tighter budget rather than multi-standard airport documentation, specifiers sometimes shortlist Fosroc’s Nitoseal PU40 — a comparable one-component, low-modulus PU sealant with 25% movement capability — as a genuine primerless alternative. Space Arc stocks and applies both, so the choice usually comes down to which standard the consultant has called out.
Fosroc Nitoseal PU40 — A specifier prioritising a lower-cost, primerless facade or window-perimeter sealant over Sikaflex Construction+’s ASTM C920 Class 35 airport/highway-grade documentation might reasonably choose Nitoseal PU40, a comparable one-component, low-modulus polyurethane sealant with 25% movement capability.
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Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.