Concrete Floor Flat Vs Level

F numbers provide architects and contractors a method of determining the flatness and levelness of a concrete floor slab.

Concrete floor flat vs level. Actually the floor must be flat which allows for minor variations in the level. Floor flatness levelnessone of the things that distinguishes a high tolerance floor is its f number requirement. The fallacy of the straightedge method was the location of the measurement. Common tolerances were 1 8 inch or 1 4 inch in 10 feet.

The scale is linear so a ff60 fl40 floor is twice as flat and level as a ff30 fl20 floor. They are calculated using the standards set forth in astm e1155 which is the standard test method for determining f f floor flatness and f l floor levelness numbers the american concrete institute indicates acceptable ranges for flatness and levelness in aci 302 1 guide. Level 1 flat a level 1 ground polish usually can be obtained by stopping below the100 grit resin bond. As an example it may be expressed at f min l 85 f min t 100 l longitudinal.

Concrete floor slab flatness and levelness traditionally allowable tolerances of concrete floor slabs were determined by checking the slab surface with a 10 foot straightedge. The ff117 fl110 floor profile on the right exhibits the typical flatness levelness of a super flat floor. Aci 302 1r 04 guide for concrete floor and slab construction american concrete institute www. The higher the f number the flatter or more level the floor.

The special fmin system of tolerance definition and measurement requires that any defects in excess of the maximum allowable variation be. The ff30 fl20 floor on the left is a moderately flat random traffic floor tolerance. Level 2 satin a level 2 honed polish is obtained by stopping at the 400 grit resin bond producing a low sheen finish. The primary reason for developing the f min system was to quantify the threshold of mast sway for preventing lift truck payload racking strikes and analyze the bumpiness of vna floors.

When you look directly down at the floor it will appear somewhat hazy with little if any clarity or reflection. The higher the number the more flat and level the floor. It spreads across uneven slabs filling in low spots as it creates a new level surface. The misconception is that a concrete subfloor must be completely level to install hardwood.

Depending on where the measurement was made the slab may pass or fail the specified. Use this self leveling concrete for mak.