Frequently Asked Questions

How is Exposeal UW applied underwater and what training or equipment does the application team need?

Exposeal UW is supplied in two-component cartridges that are dispensed using a standard dual-component dispensing gun with a static mixer nozzle — the two components are mixed in the nozzle as they are dispensed, so no separate mixing bowl or equipment is required. For above-water application (on wet but not submerged surfaces), the application team can work normally with the dispensing gun, cleaning the crack or defect with a wire brush to remove loose material, and injecting or trowelling the mixed Exposeal UW into the prepared defect. For genuinely underwater application (crack sealing on a submerged reservoir wall or marine structure), a trained diver with underwater construction experience is required — the diver works the Exposeal UW into the crack by hand or with a trowel, pressing the material firmly into contact with the wet concrete and maintaining pressure while the initial cure develops sufficiently to retain the seal without the diver holding it. The diver needs to work in a methodical sequence from the lowest point of the crack upward to prevent the uncured sealant being washed downward by the static water pressure. No special chemical hazard protection beyond standard underwater equipment is required for divers working with cured epoxy systems.

What types of cracks and joints can be sealed with Exposeal UW and are there limits on crack width or movement?

Exposeal UW is suitable for sealing static (non-moving) or minimally moving cracks and construction joints in concrete and masonry under water. The product cures to form a hard, relatively rigid epoxy — it does not have the sustained elasticity of a polysulfide or polyurethane sealant. This means Exposeal UW is appropriate for sealing static cracks (cracks that are not subject to ongoing thermal, shrinkage, or structural movement after sealing), construction joints with no designed movement allowance, and one-time closing of active cracks that have stabilised. It is not suitable for sealing expansion joints or joints and cracks that will continue to open and close cyclically under thermal or structural loading — for such active movement joints in underwater conditions, a more flexible sealant chemistry (polyurethane or polysulfide) must be used, though these products may be more difficult to apply in permanently submerged conditions. Crack widths suitable for direct trowel or injection application with Exposeal UW range from hairline cracks (where the material is worked into the crack surface) up to approximately 10 to 15 mm wide joints that can be filled by direct application. Very wide cracks and large cavities are better suited to the two-component epoxy mortar Conbextra EUW used in combination with Exposeal UW as the bonding interface.

Can Exposeal UW be used for sealing cracks in a potable water storage reservoir or does it have restrictions for contact with drinking water?

The suitability of any epoxy repair material for contact with potable drinking water depends on the specific formulation and its compliance with drinking water contact standards applicable in India. Before using Exposeal UW in a potable water reservoir — or any product in contact with drinking water — the relevant material safety data sheet and product technical data sheet must be consulted to confirm whether the product holds approval for potable water contact. In India, the Bureau of Indian Standards (BIS) and applicable state drinking water authority guidelines should be checked. For waterworks structures including potable water reservoirs, it is important to confirm with Fosroc and Space Arc Engineering that the specific batch and formulation of Exposeal UW has been evaluated for drinking water contact compliance before application. For non-potable water structures (sewage treatment, irrigation, industrial water), potable water contact approval is not required and Exposeal UW can be used on the basis of its technical performance in wet and underwater conditions.