Molds that grow in moisture can cause health disorders, and the musty smell emanating from a basement is unpleasant. Leaky foundation walls in commercial structures can cause a similar type of damage. Seepage or flowing water may occur through cracks or penetrations in concrete walls. The cause of this issue is often a failure of the waterproofing or an inadequate drainage system, which allows pressure to build up on the outside of the structure. Foundation cracks, environmental changes, and construction can all cause water damage to foundation walls.

When leaks are found in a building’s waterproofing, excavating the area and repairing the waterproofing is the usual approach. Although positive-side waterproofing is an effective and proven solution, it’s not always possible to use. For example, leaking floors are generally inaccessible from the exterior of a building.

Because of the depth of the foundation and other constraints, zero-lot line construction often makes positive side waterproofing impossible. Thankfully, newer solutions exist that allow contractors to permanently seal active water leaks from the inside (negative side) of a structure. The cost of waterproofing a leaking basement from the inside is typically less than the cost of positive-side excavation and remediation, so these techniques are becoming more popular in residential construction. Homeowners in Singapore appreciate the lower maintenance costs of keeping their bathrooms, driveways, and balconies in place. Polyurethane grouts, polymer hybrids and crystalline crack-sealing technology are just a few of the solutions available to you.

Grout Injection

For materials with long set times, flowing water on the surface of the substrate can be a problem because it can dilute or wash away the material. The standard method is to inject polyurethane foam first, stopping any flowing water; then, in a second step, to inject an elastic solid body resin. Boreholes are drilled into the crack from alternating sides in a 45° angle towards the crack center. Because the path of a subsurface crack is unpredictable, this procedure ensures that at least every second borehole intersects it. Polyurethane resin is injected into boreholes with a high-pressure injection pump that uses special valves called injection ports. Polyurethanes are the recommended adhesive for bonding to concrete and brick because they stay permanently elastic, and do not lose their adhesive qualities over time.

Crystalline Solutions

Cement-based crystalline coatings are often used in conjunction with other methods to stop active water leaks. These materials, which are marketed by several companies, are applied as a coating or grout. They do not rely on surface bonding to achieve waterproofing. Instead, reactive chemicals in the coating migrate through capillary tracts within the concrete to become an integral part of the concrete mass and seal it against moisture. They are extremely durable, even when applied to the negative side of the wall.

To analyse your water leakage, contact Le Fong Building Services, the number 1 waterproofing contractor for polyurethane injections in Singapore