Sika Sikaflex®-11 FC+
The one-part polyurethane that bonds and seals from the same cartridge — ±35% movement, primerless on most substrates, CE marked to EN 15651.
What is it?
A one-component, moisture-curing polyurethane (i-Cure technology) adhesive and joint sealant that bonds most construction substrates and seals movement joints in a single product.
Where is it used?
Facade and cladding joints, precast and masonry perimeter joints, door/window frame sealing, bonding cover plates, copings, trims, stone cladding and general construction assembly — internal and external, across Delhi NCR and pan-India project sites.
Why use it?
It skips the primer step on most substrates, cures fast enough to keep site schedules moving, and carries a genuine ±35% movement capability (ASTM C719) plus CE marking to EN 15651 — one cartridge covers both bonding and sealing jobs without switching products.
How is it applied?
Gun-applied from a 300 ml cartridge or 600 ml foil pack after standard joint preparation (backing rod, masking where needed), tooled within the roughly 70-minute skin time, and left to cure at about 3.5 mm every 24 hours.
About Sika Sikaflex®-11 FC+
Sikaflex-11 FC+ is Sika’s one-part, i-Cure polyurethane elastic adhesive and joint sealant — a genuinely dual-purpose product rather than a sealant that also sort of bonds. It moisture-cures off ambient humidity, needs no mixing, and according to Sika’s own India technical data sheet, adheres to concrete, masonry, reconstituted stone, ceramic, wood, metal and glass without surface pre-treatment on most of them. That’s the practical reason Delhi NCR facade and fit-out contractors reach for it: the same 300 ml cartridge that seals a perimeter joint around a window frame can, minutes later, bond a coping stone or ceiling trim in place — no second product, no separate primer step for routine work.
It sits in Sika’s broader Sikaflex family alongside heavier-duty options like Sikaflex-1a and facade-grade SikaHyflex-250, but FC+ is pitched at the everyday, multi-substrate job: door and window perimeters, precast and masonry movement joints, cladding trims, acoustic ceiling tiles, light fixtures. Movement capability is a genuine ±35% (ASTM C719), and the product carries CE marking to EN 15651-1 and EN 15651-4 plus ASTM C920-11 Class 35 compliance, so it isn’t a generic hardware-store PU — it’s specification-grade material with the paperwork to back it on tendered projects. Space Arc stocks and applies it as an authorised Sika distributor across Delhi NCR and pan-India sites, alongside the primers (Sika Primer-3, Sika Aktivator-205) and tooling accessories it’s designed to work with.
The technical insight
The “i-Cure” in the name is Sika’s accelerated moisture-cure chemistry — it’s what gives a roughly 70-minute skin time and a working cure rate of about 3.5 mm every 24 hours at 23°C/50% RH, noticeably quicker than a standard one-part PU of similar hardness. Combined with a soft ~37 Shore A (measured after 28 days) and ~700% elongation at break, that’s a low-to-medium modulus sealant built to move with a joint rather than crack at it — which is exactly what the ±35% ASTM C719 movement rating and the EN 15651 CC 25HM classification are certifying. Two numbers matter more than they look: the 2:1 width-to-depth joint design ratio and the 10-35 mm joint width window Sika specifies. Undersize the joint width for the expected movement, or get the depth ratio wrong, and even a technically excellent sealant will fail cohesively — this is as much a joint-design product as a material one.
Where it is used
- Bonding and sealing perimeter joints around aluminium and UPVC door/window frames into masonry openings
- Sealing movement and control joints between precast concrete panels, blockwork and masonry (10-35 mm joint widths)
- Facade and cladding joint sealing — stone cladding, ACP support framing, coping and trim joints
- Elastic bonding of copings, flashings, trims and light-gauge fixtures to concrete or masonry
- Bonding acoustic ceiling tiles, wall panels and lightweight construction elements
- General interior fit-out sealing — skirting, floor moulding and door-sill joints
- Bonding glass to metal or wood frames in shaded, non-sun-exposed applications
- Sealing air ducts, service penetrations and non-trafficked utility joints
Key advantages
- Genuine dual-purpose product — one cartridge handles both elastic bonding and joint sealing duty
- Primerless adhesion on concrete, masonry, wood, metal, ceramic and glass per Sika’s own data sheet
- High movement capability of ±35% (ASTM C719) — built to flex with real thermal and structural joint movement
- CE marked to EN 15651-1 & -4 and ASTM C920-11 Class 35 — specification-grade credentials for tendered projects
- Very low emissions — GEV-Emicode EC1PLUS, French VOC Class A+, contributes to LEED v4 EQc2 — suited to occupied interiors
- Paintable with most water-based coatings once fully cured
- Wide service temperature range, -40°C to +80°C, with good weathering and mechanical resistance
- Two pack formats — 300 ml cartridge for small repairs, 600 ml foil pack for bulk facade runs
Limitations & considerations
- Not rated for structural bonding, trafficked floor joints or structural glazing — Sika’s structural adhesive range covers those instead
- Cannot be used for permanent water immersion, swimming pools or joints under hydrostatic pressure
- Incompatible with bituminous substrates, PE/PP/PTFE plastics, natural or EPDM rubber, and alcohol-based cleaners during cure
- Full-surface (100% coverage) bonding is not recommended — the sealant core may never fully cure without air access
- India TDS lists only concrete grey as standard colour — the wider colour palette seen in some export markets isn’t guaranteed locally
- Once a cartridge is opened it must be used the same day; part-used cartridges don’t keep
Selection & best practice
Treat joint design as part of the specification, not an afterthought — keep joint width between 10 mm and 35 mm, hold a 2:1 width-to-depth ratio (Sika’s own joint-spacing table runs from 10 mm joints every 2 m up to 35 mm joints every 10 m), and always insert a closed-cell polyethylene backing rod so the sealant only bonds to the two joint faces, never the base. On porous substrates — concrete, aerated block, cement render — prime with Sika Primer-3 even though the product is technically primerless, especially on facades exposed to weathering; on non-porous metals, PVC or glazed tiles, lightly abrade and wipe down with Sika Cleaner P or Sika Aktivator-205 first. Tool the bead within the roughly 70-minute skin time, never attempt a full-surface (100% coverage) bond since the sealant core can stay uncured indefinitely without air access, and give heavy or overhead components temporary mechanical support until the 24-48 hour final-strength window has passed. Once a cartridge is opened, use it the same day.
Specifications
| Chemical base | i-Cure technology, one-part moisture-curing polyurethane |
| Density | ~1.35 kg/L (ISO 1138-1) |
| Shore A hardness | ~37 after 28 days (ISO 868) |
| Tensile strength | ~1.5 N/mm² (ISO 37) |
| Elongation at break | ~700% (ISO 37) |
| Movement capability | ±35% (ASTM C719) |
| Service temperature | -40°C to +80°C |
| Skin time / cure rate | ~70 min skin time; ~3.5 mm/24h cure rate (23°C, 50% RH) |
| Standards compliance | CE EN 15651-1 & -4 (F/PW EXT-INT CC 25HM); ASTM C920-11 Class 35 |
Industry use cases
Facade & cladding contractors
Sealing perimeter and movement joints on stone, ACP and precast facade panels across Delhi NCR high-rises, following Sika’s 2:1 width-to-depth joint design rule.
Door & window fabricators/installers
Bonding and sealing aluminium or UPVC frames into masonry and concrete openings without a separate primer step on most substrates.
General & interior contractors
Bonding acoustic ceiling tiles, coping, trims and light fixtures, plus sealing skirting and floor-moulding joints in commercial fit-outs.
Precast & masonry construction
Crack-control and movement joints between precast concrete elements and blockwork, sized per Sika’s joint-spacing table (10 mm joints every 2 m up to 35 mm every 10 m).
MEP & utility contractors
Sealing service penetrations, air-duct joints and non-trafficked utility openings where a flexible, primerless PU sealant saves a separate site visit.
Frequently asked questions
Is Sikaflex-11 FC+ different from the older Sikaflex-11 FC?
Do I need to prime the surface before applying it?
Can I use it to seal a water tank or swimming pool joint?
How much area does one cartridge actually cover?
Can Sikaflex-11 FC+ be painted over?
Is it suitable for structural glazing or heavily trafficked floor joints?
How we position Sika Sikaflex®-11 FC+
Within Sika’s own range, Sikaflex-11 FC+ is the multipurpose workhorse — for movement joints wider than 35 mm or heavier facade-grade weathering demands, specifiers typically step up to SikaHyflex-250 Facade or Sikaflex-1a; for structural glazing or genuinely load-bearing bonds, Sika’s Sikadur or SikaFast structural adhesives are the correct family, not FC+. On priming and cleanup it’s meant to be paired with Sika Primer-3, Sika Aktivator-205 and Sika Remover-208 rather than substituted for them. Outside the Sika stable, Fosroc’s Nitoseal PU40 — a one-part, low-modulus polyurethane sealant rated ISO 11600 Type F Class 25LM — is the closest genuine alternative when the brief is strictly joint sealing rather than the bond-and-seal duty FC+ is built for; a specifier already standardised on Fosroc’s Nitoseal range, or one who only needs the sealant half of this product’s job, may reasonably choose PU40 instead. Space Arc supplies and can advise on both lines.
Fosroc Nitoseal PU40 — If the brief is purely a low-modulus movement-joint sealant rather than the bond-and-seal hybrid duty Sikaflex-11 FC+ is built for, Fosroc’s Nitoseal PU40 (ISO 11600 Type F Class 25LM) is a genuine like-for-like alternative — a reasonable pick for a specifier already standardised on the Fosroc Nitoseal range.
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Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.