Concrete Floor Tolerances – How Flat Does The Floor Need To Be?

Surface Regularity

Application

FM1

Where high standards of flatness are required, this may require constructing in long thin bays.

FM2
Where wide isle racking or stacking are used over 8m high.

FM3
Where wide isle racking or stacking are used up to 8m high. Also used for retail and manufacturing areas. Suitable for foot traffic.

FM – Free Movement

Free movement is an area where fork lifts, vehicles and foot traffic can move in any direction over the floors surface.
Category 1, 2 and 3 tolerances are used when providing details of areas that have specific traffic movements. For example high reach forks lift truck that follows a pre-determined path along a picking.
For further information please refer to British Standards BS EN 8204:2 for screeds and Concrete Society technical paper 34 2003 third edition for further guidance.

The 3 m grid survey should be carried out using a precise level and staff as in Section 7.12 of TR34. Property II controls flatness and requires the difference in slope over 600 mm to be surveyed. Property II should be measured along lines that are uniformly distributed on the 3 m grid across the floor and which are used to assess property IV. The uniformity is required to ensure that the survey gives a reasonable sample assessment of the free movement area. This is achieved by using lines of the same length and ensuring that no readings are taken within 1500 mm of walls or columns.