When a drainage system malfunctions and foundation waterproofing is not sealed anymore, water seeps through the foundations. As a result, the dry materials inside absorb moisture and eventually rot. This mold is harmful to the health of the occupants and that mold must be removed professionally. The solution? Install a French drain according to the rules of the art and waterproof the foundations. The foundations will take a few months to completely dry up and the occupants can finally rebuild securely.