Surface Regularity / Straight Edge Tests

Surface regularity can be checked with the use of a straight edge.

This method of testing is described in both BS8204-Part 1:2003 and BS8204-Part 2:2003. A 2m straight edge is used in both specifications. These are usually but not always specified on mezzanine decks or retail units where tiling is to be received.

Basic Method of Measuring Surface Regularity

  1. A 2m straight edge is placed in contact with the floor and resting under its own weight.
  2. Measure the greatest gap from the underside of the straight edge, between the points which are in contact with the floor surface. This is done by means of a ‘go’ ‘no go’ method. The measurements are taken by means of a slip gauge.

Watch Our Surface Regularity Testing Video

Straight edge tests can be carried out to check for compliance with British Standards BS8204 Part 2 : 2003 to see if the SR1, SR2, or SR3 classifications are being achieved.

It should be noted that both British standards state that ‘Where the straight edge basis for specification is used it is advisable for the various interested parties in a contract to agree the sampling rate for testing the floor to check conformity, and the procedures to adopt if conformity is not achieved, before the floor is constructed. Such agreement should include the number of positions where the straight edge will be placed to check conformity’

If the rate of testing is not known, then we would recommend the following formula to calculate the minimum number of straight edge tests.

Floor area M²/20 = Minimum number of straight edge tests.

The location and orientation of tests can be discussed by calling Face Consultants on +44 (0) 1484 600090. It may be necessary to ensure repeatability in the case of any dispute.

Related Documents

2 Metre Straight Edge Test

2m Straight Edge Test

Maximum gap under a 2m straight edge being measured on site by a Face engineer.

3 Metre Straight Edge Test

3m Straight Edge Test

We can also carry out Straight edge tests using a 3m straight edge, on feet, for checking plus or minus deviations from a given number over a 3m length. For example, checking for no more than plus or minus 5mm under a 3m straight edge.

Measurement Standards

TR34 4th Edition

TR34 4th Edition

The Concrete Society’s TR34 Free Movement (4th Edition) Classifications

TR34 3rd Edition

TR34 3rd Edition

The Concrete Society’s TR34 Free Movement (3rd Edition) Classifications

Surface Regularity

Surface Regularity

can be checked to ‘BS 8204-2:2003+A2:2011’ straight edge specifications SR1, SR2 and SR3

Comparison table for Free Movement Specifications

Flatness Comparisons

Comparison table for Free Movement Specifications

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