Resilient flooring may be acceptable over lightweight aggregate concretes having dry densities greater than 90 lbs per cubic foot and cellular concretes having plastic (wet) densities over l00 lbs per cubic foot (94 lbs dry weight), providing the surface is troweled to a smooth, even finish. This is a minimum requirement for the application of resilient floor covering. Concrete slabs with heavy static and/or dynamic loads should have higher design strengths and densities calculated to accommodate such loads.
Because lightweight concrete can retain significant amounts of moisture within the slab, it is imperative that lightweight floors be tested for moisture in accordance with ASTM F 2170, “Standard Test Method for Determining Relative Humidity in Concrete Floor Slabs Using in situ Probes.”
DO NOT TEST LIGHTWEIGHT CONCRETE FLOORS USING ASTM F 1869, “Standard Test Method for measuring Moisture Vapor Emission Rate of Concrete Subfloor Using Anhydrous Calcium Chloride.” This test method does not indicate the moisture condition deep within a slab and can be especially misleading when used on lightweight concrete slabs.
All recommendations and guarantees regarding their suitability as substrates for resilient flooring must be the responsibility of the manufacturer and installer of the substrate.