Sika Waterbar® FB-125 Hybrid FPO Internal Waterstop — Construction Joints
Hybrid waterstop with rough textured surface based on flexible polyolefin (FPO). Placed into fresh concrete and becomes fully embedded in the cured concrete, providing a fully bonded, durable watertight seal that prevents any lateral water underflow at construction joints.
Sika Waterbar® FB-125 is cast directly into the fresh concrete pour. The rough-textured FPO surface bonds mechanically and chemically to both concrete pours, forming a continuous watertight barrier that spans the construction joint without requiring surface preparation or adhesive.
The flexible polyolefin (FPO) base maintains its sealing performance under UAE's sustained 45°C+ construction site temperatures and high groundwater chloride levels. Suitable for UAE coastal environments where saline, sulphate-rich groundwater is present across Dubai, Abu Dhabi, Sharjah, and Ras Al Khaimah underground structures. Remains flexible in cold weather — no embrittlement during winter working temperatures.
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What is Sika Waterbar® FB-125?
Sika Waterbar® FB-125 is a hybrid waterstop with a rough textured surface based on flexible polyolefin (FPO). It is designed to seal construction joints as an internal waterstop in watertight concrete constructions. The waterstop is placed into the fresh concrete and becomes fully embedded in the cured concrete, providing a fully bonded, durable watertight seal that prevents any lateral water underflow along the joint plane.
The rough-textured FPO surface bonds mechanically and chemically to both sides of the concrete joint without requiring additional adhesive or surface preparation. This fully bonded system eliminates the migration path for water along the waterstop-concrete interface — a key failure mode in conventional smooth-profile waterstops. Supplied as a single roll of 50 m wrapped in protective foil.
Typical Applications
Key Performance Benefits
- Fully bonded — rough textured FPO surface bonds to concrete, eliminating lateral water underflow
- Hybrid FPO material — combining flexibility, chemical resistance, and long-term durability
- Internal waterstop — completely embedded in cured concrete with no exposed components
- No adhesive or primer required — bonds directly to fresh concrete on both sides
- Maintains flexibility across wide temperature range — suitable for UAE climate extremes
- Chemical resistance to saline groundwater, sulphates, and mild acids — UAE coastal groundwater rated
- Remains permanently flexible — accommodates minor structural movement at the joint
- Simple installation — positioned and supported during concrete pour without complex fixturing
Pour Part A liquid into a clean container. Gradually add Part B powder while mixing using a slow-speed drill with paddle mixer. Mix until a uniform, lump-free slurry is obtained. Use the full pre-measured kit — do not split partial packs unless quantities are weighed accurately.
Material Properties
| Base Material | Flexible polyolefin (FPO) — hybrid formulation |
| Surface Finish | Rough textured — both faces |
| Width | 125 mm |
| Flexibility | Permanently flexible — no embrittlement |
| Bond Mechanism | Mechanical and chemical bond to concrete |
| Chemical Resistance | Saline groundwater, sulphates, mild acids and alkalis |
| Temperature Range | Remains flexible at low temperatures — suitable up to 45°C+ UAE conditions |
| Water Direction | Prevents lateral water underflow along joint plane |
Application & Site Parameters
| Joint Type | Construction joints (internal waterstop) |
| Installation Method | Cast into fresh concrete — placed at joint line |
| Adhesive / Primer | Not required — bonds directly to fresh concrete |
| Concrete Cover | As per structural engineer specification |
| Concrete Compatibility | All standard and watertight concrete mixes |
| Suitable Applications | Basements, water tanks, pools, reservoirs, retaining walls, water treatment |
Packaging — UAE
| Standard Roll | 50 m length, foil wrapped for site protection |
| Width | 125 mm (FB-125 designation) |
Application Guide — UAE Site Conditions
Follow these steps for correct installation of Sika Waterbar® FB-125 as an internal construction joint waterstop in UAE's hot, coastal, and high-groundwater-pressure environments.
Review Joint Design & Specification
Before installation, confirm the joint design with the structural engineer. Sika Waterbar® FB-125 is designed for construction joints — pour joints where concrete is cast in sequential pours. Verify the specified concrete cover over the waterstop on both sides. Ensure the joint line is clearly marked on the formwork and reinforcement.
Positioning & Fixing in Formwork
Position the Sika Waterbar® FB-125 centrally at the joint line, ensuring the waterstop sits at the correct depth within the concrete section. Fix the waterstop in position using wire ties to the reinforcement at maximum 500 mm centres — the rough-textured surface must remain clean and free from contamination before and during the concrete pour. Do not allow concrete slurry, oil, or mud to coat the textured surface before the pour.
Mixing & Workability
Mix to the standard duration and speed for the mortar or concrete type. Sikalite® AE will be uniformly distributed throughout the mix once the normal mixing cycle is complete. The workability of the mortar or concrete may be slightly modified by the admixture — adjust gauging water within the limits of the approved water/cement ratio to achieve the target consistency. Do not over-water the mix to compensate for stiffening.
Application of Mortar or Concrete
Place, compact, and finish the mortar or concrete in the normal way for the application type. For screeds, compact thoroughly to eliminate voids and achieve a dense, uniform surface. For renders, apply in layers of appropriate thickness and finish to the specified surface texture. For concrete, compact fully using internal vibrators to eliminate honeycombing — the waterproofing benefit of Sikalite® AE is dependent on a dense, well-compacted concrete matrix.
Curing
Cure the mortar or concrete in accordance with standard good practice and the project specification. In UAE hot weather, curing is critical — inadequately cured concrete or mortar will lose strength and watertightness regardless of the admixture used. Apply wet hessian, polythene sheeting, or a compatible curing compound immediately after finishing and maintain for the full specified curing period.
Construction Joints Only
Sika Waterbar® FB-125 is designed for construction joints — sequential pour joints. It is not suitable for movement joints, expansion joints, or settlement joints where significant differential movement is expected. Specify Sika Waterbar® movement joint profiles for these applications.
Surface Contamination
The rough-textured FPO surface must remain clean before and during the concrete pour. Oil, mud, concrete slurry, or construction dust on the bonding surface will prevent full concrete-to-waterstop adhesion — the primary failure mechanism in bonded waterstop systems.
Concrete Consolidation
Poor vibration around the waterstop profile creates voids and honeycombing adjacent to the FPO surface — providing a direct water migration path that bypasses the waterstop. Vibration at close centres around the waterstop zone is mandatory, not optional.
Recommended System Products
Combine Sika Waterbar® FB-125 with these Highway BMT-stocked Sika products for a complete construction joint waterproofing and below-grade protection system across UAE residential, commercial, and infrastructure environments.