This picture shows the foundation installed on impervious soil (clay) where water ponding is approximately 4" deep.

Concrete is hygroscopic, adsorbing moisture from adjacent soils and water ponds. This moisture wicks through the concrete where it diffuses into the interior of the building, leading to excess humidity, chronic dampness and mold.

Concrete footings, located at the bottom of the excavation, are exposed to water ponding, the severest form of moisture contact.

The contractor will soon apply a dampproof coating to the foundation wall and install drain pipe and 150mm of drain rock. However these measures will not prevent water ponding and the building suffer from rising damp for the rest of its life.

For additional information on water ponding and its prevention, click on the links below:

• Different soil types and water ponding;

• Correct installation to prevent water ponding;

• Pictures of excavations with water ponding;

• Printable report on water ponding, drainage & rising damp;