BRE Drop Hammer Screed Testing

BRE Screed Tester

If the floor screed is breaking up, cratering  or there is loss of adhesion form the resilient floor finish  (vinyl, Amtico etc.) or rigid ceramic or natural stone tiles to the screed, the failure could be a lack of compaction of the screed. One method of testing the screed is by using The BRE Screed tester.

The BRE Drop hammer Test is an in situ crushing resistance (ISCR) test designed to test the strength and compaction of the screed as outlined in BS8204-1:2003 + A1:2009 Annex E.

The test consists of either a 4 kg drop weight for categories A, B and C screeds or 2 kg drop weight for category C floating screeds. The weight is dropped vertically four times in succession from a height of 1 m onto an anvil of 500 mm² and the indent is measured with a specific digital depth gauge.

Acceptance limits for in situ crushing resistance test are given Table 4 of BS8204-1:2003+A1:2009.

Table 4 of BS8204-1:2003 + A1:2009

Category Depth of indentation Depth of indentation
Bonded & unbonded screeds Floating screeds
A 3 mm 3 mm
B 4 mm 4 mm
C 5 mm 2.5 mm (2kg weight)

The above test can be carried out by our on-site testing team who all have a scientific background. Written notes are taken throughout with locations, and descriptions being clearly marked with strict reference to all relevant British or European Standards. If litigation is then considered at a later date the testing procedure will stand the scrutiny of the courts. The reasons for the failures can be confirmed by laboratory analysis for mix proportions, aggregate grading and critical void measurements if subsequently required.

As can be seen  by the photograph on this failed floor screed the indent  measures 11+ mm way outside the acceptable limits given in Table 4 of BS8204-1:2003 + A1:2009.

Due to the extent of the failure in this particular investigation a core was then cut  out of  the screed for further laboratory analysis, the picture  highlights the  lack of compaction  towards the surface of the screed compared to the base.