Stanley Watras had worked as an engineer for 11 years at a nuclear power plant in Pennsylvania. At the end of each workday, he and other plant employees were checked by a monitor that measured radiation levels. This procedure ensured that they had not been contaminated by unsafe levels of radioactivity while at work.
In December 1984, Watras suddenly began setting off the buzzers on the radiation monitors as he walked by the machine on his way out of the building. The readings showed high levels of contamination over his entire body. For several days this scenario was repeated, with Watras subjected to a lengthy decontamination ordeal. Where was Watras picking up this radioactivity and why was it affecting only him?
The mystery was solved when Watras decided one morning to go through the monitors at the exit door as he entered the workplace. When the alarms went off, Watras immediately realized that the radiation was coming from somewhere outside the nuclear power plant. The local elec-
plugs the pores and capillary tracts of concrete. Xypex Concentrate can be used as a single-coat dampproofing membrane or in a two-coat system with Xypex Modified. Xypex Modified can be used alone where dampproofing is required.
Fluid-Applied Dampproofing
• AFM Safecoat DynoFlex: A topcoat for use over DynoSeal
• AFM Safecoat DynoSeal: A flexible vaporproof barrier
• Rub-R-Wall: Asphalt-free moisture resistant membrane products for various foundation applications
Bentonite Dampproofing
• Volclay: A self-healing bentonite-based moisture resistant panel
Under some conditions, water will move upward through the soil by capillary action. This type of moisture invasion can be controlled by creating a capillary break. Half-inch minimum gravel, free of smaller fines, placed under a slab will stop capillary action. A dampproofing coating or membrane should also be applied between the footing and the stem wall or the stem wall and the framing to stop any moisture from being carried up through the concrete and entering the framing.
