Floor Type #2 - Plastic Grid with Filter Fabric Backing
A 4 ft by 150 ft roll of plastic grid with a geotextile backing was used to create this treatment. A base layer of filter fabric, topped with six inches of dense grade aggregate (DGA) was placed and leveled within two inches of the final grade. Four strips of a two-inch layer of interlocking plastic grid, with a filter fabric backing, was placed on the rock, connected, and then backfilled with DGA.
The ease of installing the plastic roll made it a nice choice. However, the gravel had to be completely level before adding the plastic grid with the geofabric backing. Otherwise, voids could produce deflection or an unwanted hollow feel when walking on it. Experience with other plastic grid materials indicate that, for this application, it would be easier and possibly better if we had used the roll without the fabric backing. This would allow the installer to lift the grid where needed, with the rock installed, which allows the rock to fall out, and create a level surface.
Below are some close up pictures of the plastic grid with the geofabric backing.