Apparatus for forming a foamed outdoor protective cover layer

An apparatus for applying a sprayable foamed composition for forming a cover layer over a selected material, the apparatus comprising:

• a storage tank adapted to contain a slurry including ingredients of a sprayable composition for forming a cover layer over a selected material, said storage tank having an outlet port;
• a pump adapted to pump said slurry, said pump having an intake port and a discharge port, said pump intake port connected to said storage tank outlet port;
• a regulating valve having first and second inlet ports and an outlet port, said regulating valve operable to vary the amount of flow from said second inlet port to said outlet port, said first inlet port being coupled to said pump discharge port;
• a spray nozzle connected to said outlet port of said regulating valve;
• and
• a foam generator connected to said second inlet port of said regulating valve, said regulating valve being operable to combine foam produced by said foam generator with said pumped slurry to produce a foamed composition, said regulating valve being adjustable to vary the rate of addition of foam to said pumped slurry to control the density of said foamed composition.