Structural Floor Flatness

  • FF = 38 (SOV)
  • FF = 25 (MLV)
  • Kinetics requires a specified overall value of Floor Flatness FF = 38 and a minimum local value of Floor Flatness FF = 25. This means that locally the floor is considered “Flat” and globally the floor is considered “Good” (“Flat” and “Good” are terms defined by ACI- American Concrete Institute Guidelines Section 302). Conventionally this means locally a 10 foot straight edge would have 1/4 inch of variation, and globally the variation would be less than 3/16 inch.
  • These requirements are necessary for Kinetics spring lift slabs because the top of the structural floor becomes a pouring form for the bottom of the isolated slab. As the canisters are a fixed height, inconsistencies in the structural floor become reflected in the isolated slab. If the structural floor is not considerably flat then issues can arise that adversely affects the acoustical, and even possibly the structural performance of the isolated, elevated slab. The standard deviation of varying thickness of the slab could be significantly more than was accounted for in the selection of the isolators; this could lead to under or over isolation, incorrect leveling screw set dimensions, and structural stress in the isolated slab. This can also make lifting the slab to a constant elevation very difficult.
  • Normally FL is typically specified with along with these numbers for levelness. While flatness between mounts is critical, the slope of a floor is not nearly as crucial. Please contact Kinetics if a sloped floor is being considered with spring isolated slabs.