Concrete Slab Flatness Tolerances Uk

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Concrete slab flatness tolerances uk.

5 it is not possible to construct concrete floor. All points should be within 15mm from planned level. The higher the f number the flatter or more level the floor. Specialist tolerances can be agreed between client designer and contractor.

The fl number relates to the general floor slope of a concrete slab from an assumed datum elevation. An 100 flat and level concrete floor will be at a 90 degree angle to the wall and. Flatness and levelness tolerances. You may assume that both are identical measurements however a concrete floor slab can be flat but not level and visa versa.

All points should be within 15mm from planned level. Note that flatness is a result of good finishing while levelness is a result of good screeding followed by finishing processes that don t undermine the screeding. Section 9 precast concrete 22 100 9 1 general 22 100 9 2 precast concrete products 23 101 9 3 precast concrete elements 23 101 9 4 handling and storage 23 101 9 5 placing and adjustment 24 101 9 6 jointing 24 101 section 10 geometric tolerances 24 102 10 1 general 24 102 10 2 overall structure 25 104. 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.

Fm tolerance concrete floors are surveyed according to flatness and levelness. Concrete slab surface flatness also referred to as surface regularity surface flatness must not be confused with surface level relative to a fixed datum. As recognised in bs 8204 2 mcrma technical paper no 13 sci publication p300 and concrete society s good concrete guide no. 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.

The allowed deviation varies from 3 to 10mm depending on the flatness designation. However as shown in table 12 10a sr1 is not achievable on metal decking suspended floors. The difference in elevation of two points which are 10 0 apart are measured as the value. F numbers were developed in the 1980s to provide a systematic quantitative way to indicate the flatness and levelness of a concrete floor.

Table 12 10a extract from smd tgn online and bs 8204 gives three tolerances for floor flatness. F numbers provide architects and contractors a method of determining the flatness and levelness of a concrete floor slab. How is the tolerance of a concrete floor measured. The fallacy of the straightedge method was the location of the measurement.

Floor flatness levelnessone of the things that distinguishes a high tolerance floor is its f number requirement. Common tolerances were 1 8 inch or 1 4 inch in 10 feet.