What are FF and FL numbers?
Let’s start off with the basics: Floor Flatness (FF): The FF number essentially tells you how flat your concrete floor is. Bumps and grooves cause your Floor Flatness numbers to drop. Higher F-numbers equal flatter floors. Floor Levelness (FL): The FL number indicates if you have any tilts or pitches in the slab.
What is floor levelness?
Floor Levelness (FL) Levelness depicts how closely the finished floor matches the intended slope indicated in the design documents. Elevation differences are measured every 10-feet within 72 hours after the concrete is placed and those measurements are entered into a calculation to determine floor levelness (FL).
How do you determine the slope of a floor?
Slope can be calculated as a percentage which is calculated in much the same way as the gradient. Convert the rise and run to the same units and then divide the rise by the run. Multiply this number by 100 and you have the percentage slope. For instance, 3″ rise divided by 36″ run = .
What does FF mean on site plans?
Finished Floor Elevation
Also referred to as FF is Finished Floor Elevation. The term FFE refers to the top of the structural slab and its elevation above sea level. FG. Finished grade. The term FG refers to the elevation above sea level for the finished grade or finished ground.
What is a normal floor slope?
Floor slope is not uncommon, especially in homes more than 15 years old. According to the National Association of Home Builders (NAHB), floor slopes less than ½ inch (1.27 cm) over a distance of 20 feet (6.10 meters) are acceptable. Other experts say that anything under 1.5 inches (3.8 cm) is okay.
How do I know if my concrete slab is level?
You want to measure any gaps between the surface and the level. And if it’s less than 1/8 of an inch, it’s considered level. Larger gaps will require more pouring or some other type of adjustment. Mark these areas with a felt-tipped marker, and repeat the process until the entire area has been measured.
What’s the f number for a concrete slab?
F-number measurements are standardized under ASTM E 1155 “Standard Test Method for Determining F F Floor Flatness and F L Floor Levelness Numbers” and the ACI 302.1R-04 “Guide for Concrete Floor and Slab Construction” provides F-number recommendations for hard-troweled slabs-on-ground and suspended slab surfaces.
Which is higher fmin100 or Superflat floor requirement?
Lift and forktruck manufactures publish recommended Fminfloor tolerances to assure the proper operation of their equipment. The higher the number the flatter and more level the floor requirement is. Fmin100 is typically referred to as a “Superflat” floor requirement.
When to use super flat or super level concrete floors?
According to ACI 117, random-traffic concrete floors are classified as follows. Keep in mind that levelness is only used for slab-on-grade placement. Super flat floors require special skill and equipment to achieve and should only be used for the most critical of concrete floors in specialized programs like television studios.
Which is an example of a concrete slab finishing specification?
Concrete Slab Finishing Specification Example: The following is an example of a performance-based specification for concrete finishing as it relates to the F-Number system. Red text that is located within brackets indicates alternate or optional items depending on the nature of the project: