Method of preventing intrusion of toxic vapor into indoor air

A method for preventing intrusion of toxic contaminants into the interior air space of a building built upon a concrete foundation through which said contaminants permeate and contaminate the interior air space, the method comprising the steps:

• a. detecting the presence of contaminants within the building's interior air space or in nearby soil or groundwater;
• b. preparing the top surface of the building's concrete foundation for receiving a topical application of a material;
• c. applying a first layer of material upon said top surface of said concrete foundation and allowing said first layer to dry;
• d. applying a second layer topcoat upon said layer formed in step c), said first and second layers reacting with one another to define a material operative to form a barrier preventing said contaminants from permeating through said foundation and into said interior air space of said building.