A Good Foundation is Waterproof

Water ingress can cause serious damage to the concrete foundations or basement areas of a building. Effective waterproofing solutions that prevent water migration are, therefore, essential to prevent costly damage, visual deterioration and health risks.

Jyoti Seth, Global R&D Director, Residential Building Envelope at GCP Applied Technologies, explains how innovation has enabled long-term, structural integrity…

Concrete has been long-established as a durable material for construction. Its composition, however, can crack while setting allowing groundwater and atmospheric contaminants to penetrate its porous surface. This is particularly acute in coastal sites, which are exposed to high levels of sulphates and chlorides through saline groundwater and aggressive atmospheric conditions.

Chemicals such as chloride ions from seawater or airborne salts can diffuse into concrete through cracks and pores in the material and cause corrosion of steel reinforcement. The corrosion buildup on the steel can cause the concrete to crack further and create more paths of contamination. Dampness in structures designed for habitation can even cause health risks to their inhabitants. In worst case scenarios, corrosion buildup can compromise the structure's integrity.

Preemptive measures

The necessity to protect concrete against the ravages of pernicious water and chemicals has led to innovations that effectively prevent water ingress into basement structures. These include a variety of bonding technologies, but only one provides truly intimate cohesion to concrete for a fully-bonded, impenetrable seal: PREPRUFE®.

During the pour, the concrete passes through the microporous top layer to the adhesive layer of the Preprufe, where mechanical and adhesive forces combine at the concrete/membrane interface to create a continnuous bond and seal that prevents water migration and reduces the risk of leaks.

Without Preprufe

Leaks, such as those caused during installation from site issues, can pose a major problem with some membrane solutions that don't adequately prevent water migration.

For example, a failure to seal a membrane against supporting piles, or minor tears in a membrane can allow water to migrate between the membrane and the concrete, whether under pressure or by capillary action. It will then seek out cracks or construction joints and can result in a significant head of water in deep basements.

The biggest headache for project teams is locating these leaks, which are often a considerable distance from the actual source. In some cases, a leak can take months to locate. In that time, the concrete could be exposed to contaminated groundwater, further exacerbating an already expensive problem.

In contrast, Preprufe prevents this costly phenomenon in foundations. In the event of a puncture to the waterproofing membrane, the intimate bond between the concrete and Preprufe's adhesive layer prevents penetrating water from migrating and finding a way into the concrete.

Other waterproofing solutions don't measure up

Competing mechanically-bonded membranes have recently been introduced which combine a sheet membrane fixed to a fleece or plastic mesh. The mesh becomes encapsulated in the surface of wet concrete. However, no matter the mechanically-bonded option chosen, only a partial bond forms with the concrete. Even tiny areas where the sheets do not adhere completely to the concrete won't guarantee the prevention of water migration between the concrete and membrane.

In fact, these systems are more likely to conceal the sources of leaks, thus prolonging the project and driving up costs.