Sika Sikaflex Construction+
One-component, moisture-curing i-Cure polyurethane sealant engineered for movement and connection joints in concrete and masonry facades across Indian climates.
What is it?
A single-component, moisture-curing elastic polyurethane joint sealant built on Sika’s i-Cure technology, formulated for facade and connection joints between porous and non-porous substrates.
Where is it used?
Movement and connection joints on concrete and masonry facades, precast panel joints, infill panels, cladding and curtain walling, for both interior and exterior exposure.
Why use it?
It absorbs structural and thermal movement of up to plus or minus 25% (ISO 9047) while resisting weathering, cures bubble-free even in hot, tropical conditions, and is over-paintable.
How is it applied?
Gun-applied from 600 ml foil packs into a correctly designed joint with a closed-cell backing rod, then firmly tooled against the joint faces; priming is only needed on critical or highly stressed substrates.
About Sika Sikaflex Construction+
Sikaflex Construction+ is Sika’s workhorse gun-grade sealant for the joints that decide whether a facade stays weathertight over its service life. It is a one-part polyurethane that cures by reacting with atmospheric moisture, so there is no mixing on site and no pot-life clock to beat. The i-Cure chemistry underneath it is what sets it apart from older PU sealants: the curing reaction releases far less gas, which means the bead cures bubble-free even when it is being gunned in the peak summer heat of a Delhi or Chennai site. That single property removes one of the most common causes of joint failure in Indian conditions, where a conventional sealant can foam and blister as it skins over in high ambient temperatures.
For a distributor’s engineering audience, the appeal is that one product covers a wide slice of the facade envelope. It bonds to concrete, aerated concrete, brick, cement renders and mortars on the porous side, and to aluminium, anodised and powder-coated metals, galvanised and stainless steel, glazed tiles and PVC on the non-porous side. That means the same cartridge handles the precast panel joint, the window perimeter against the reveal, and the cladding-to-frame connection, cutting down the number of SKUs a contractor has to carry to a facade job. Once cured it stays elastic across a service band of minus 40 to plus 70 degrees Celsius and can be over-painted with most flexible facade coatings, so it disappears into the finished elevation rather than dictating it.
The technical insight
The behaviour that matters in a facade joint is movement accommodation, and here the product is genuinely elastic rather than merely flexible. It is rated at plus or minus 25% movement to ISO 9047 and plus or minus 35% to the more demanding ASTM C 719 cyclic protocol, backed by roughly 90% elastic recovery (ISO 7389). In practice that means after the joint opens in winter and closes in summer, the sealant springs back to shape season after season instead of taking a permanent set and pulling away from one face. A low secant tensile modulus of about 0.45 N/mm2 at 100% elongation (at 23 degrees Celsius) keeps the stress the sealant transfers back into the substrate low, which protects weaker arrises on concrete and render from being torn out. The high tensile strain at break of around 800% (ISO 37) and tear propagation resistance near 7.0 N/mm give it the reserve to survive the occasional over-extension that real buildings impose. The i-Cure moisture-cure advances at roughly 3 mm every 24 hours at 23 degrees Celsius and 50% relative humidity, with a skin forming in about 65 minutes, so deep joints keep curing through their section while the surface is already tooled and protected.
Where it is used
- Movement and connection joints on concrete and masonry facades
- Joints between precast concrete elements and infill panels
- Perimeter sealing of windows and door frames against reveals
- Cladding and rainscreen connection joints
- Curtain walling and framing perimeter joints
- Interior connection and crack-control joints in dry areas
- Sealing between dissimilar porous and non-porous substrates
- General facade weather-sealing on multi-storey buildings
Key advantages
- Bubble-free cure even in hot, tropical Indian site conditions thanks to i-Cure technology
- High movement capability of plus or minus 25% (ISO 9047) and plus or minus 35% (ASTM C 719)
- Around 90% elastic recovery, so the joint keeps returning to shape season after season
- Adheres to a wide range of porous and non-porous substrates, often without a primer
- Over-paintable with most flexible facade coating systems
- Very low VOC emissions, EMICODE EC1PLUS R rated, and LEED v2009 contributing
- Backed by EN 15651-1, ISO 11600 and ASTM C 920 class 35 approvals
- Single-component and ready to use, with no on-site mixing
Limitations & considerations
- Not suitable for natural stone, where staining and bleed can occur
- Must not be used on bituminous substrates, natural rubber or EPDM, or materials that bleed oils and plasticizers
- Not for joints under permanent water immersion or hydrostatic water pressure
- Not recommended in and around swimming pools
- Uncured sealant must be kept away from alcohol-containing products, which disrupt the cure
- White shades can show cosmetic colour change under prolonged UV and chemical exposure (aesthetic only)
Selection & best practice
Design the joint before you order the sealant: keep a width-to-depth ratio of 2:1 with a joint width between 6 mm and 50 mm, and size movement joints from the joint spacing (for example a 20 mm width at 6 m spacing for plus or minus 25% joints). Make sure joint faces are clean, dry, sound and free of oil, grease, dust and curing-compound residue. Insert a closed-cell polyethylene backing rod to set the depth and prevent three-sided adhesion, then prime only where the application demands it, using Sika Primer-3 N on concrete and porous substrates and Sika Aktivator-205 on metals and glazed tiles, respecting the flash-off windows. Gun the bead into full contact with both faces without trapping air, then tool firmly within the roughly 65-minute skin time, using Sika Tooling Agent N and never a solvent, and pull any masking tape before the skin forms.
Specifications
| Composition | 1-part, moisture-curing i-Cure Technology polyurethane |
| Movement capability | +/-25% (ISO 9047) / +/-35% (ASTM C 719) |
| Shore A hardness | ~28 after 28 days (ISO 868) |
| Elastic recovery | ~90% (ISO 7389) |
| Tensile strain at break | ~800% (ISO 37) |
| Service temperature | -40 C to +70 C |
| Curing rate / skin time | ~3 mm per 24 h; skin ~65 min (23 C, 50% r.h.) |
| Joint design | Width 6-50 mm; width-to-depth ratio 2:1 |
| Packaging & colours | 600 ml foil packs; white, cream white, beige, concrete grey, jasmine |
Industry use cases
Commercial & high-rise facades
Sealing precast panel, cladding and curtain-wall connection joints on multi-storey elevations where high movement and weather resistance are non-negotiable.
Residential & institutional buildings
Weather-sealing window and door perimeters and masonry connection joints on apartment blocks, schools and hospitals across Delhi NCR.
Precast concrete construction
Elastic sealing of joints between precast elements and infill panels, accommodating erection tolerances and thermal movement.
Metal cladding & framing
Bonding and sealing aluminium, powder-coated and galvanised metal cladding to structural frames with a low-modulus, paintable bead.
Fit-out & interior joints
Interior connection and crack-control joints between dissimilar dry substrates where a durable, over-paintable finish is wanted.
Frequently asked questions
Does Sikaflex Construction+ need a primer?
How much movement can the joint take?
Can I paint over it?
Is it suitable for natural stone or swimming pools?
What joint size and pack should I plan for?
Will it cure properly in Indian summer heat?
How we position Sika Sikaflex Construction+
Within the Sika range, pair Sikaflex Construction+ with Sika Primer-3 N and Sika Aktivator-205 for critical substrates, Sika Tooling Agent N for a smooth finish, and Sika Remover-208 for equipment cleaning; where a paintable, non-yellowing hybrid is preferred for exposed weather-lines, Sikaflex-11 FC+ or an MS-based Sika sealant are worth comparing. Across our other brands, we can also supply Dr. Fixit and STP polyurethane and polysulphide sealants for allied joint work. For fuel- and chemical-exposed horizontal pavement joints, this facade-grade product is not the right tool; specify a pouring-grade sealant instead.
Fosroc Nitoseal MS600 — A specifier who wants a paintable, non-yellowing, low-odour hybrid with the same plus or minus 25% movement class may prefer this MS-polymer alternative over an i-Cure polyurethane on exposed weather-lines.
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