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Testing Cement-Sand Screeds

Using the BRE screed tester

Classification for soundness
Cement-sand screeds should be specified to comply with one of Soundness Categories set out in BRE Information Paper IP 11/84.

Table 2 gives the maximum allowable indentation depths for categories "A", "B" and "C". These categories are also recommended in BS 8203.

Recommendations on the selection of screed categories are contained in the BCA publication Floor Levelling Screeds and these are as follows:

Select a category "A" screed for floors which take very heavy traffic and where failures are unacceptable or the cost of repairs and consequential loss is extremely high. For instance, hospital operating theatres, casinos, etc. Select a category "B" screed for floors taking heavy traffic such as those in commercial premises and a category "C" screed for lightly trafficked floors such as those in offices and houses.

Category Acceptance limits (4 drops of the weight)
Indentation depth not to exceed *
Random Tests Grid Tests
A 2 mm 3 mm
B 3 mm 4 mm
C 4 mm 5 mm

Table 2: Classification of screeds for soundness
* 10% of readings may exceed limits by 1mm.

References


ROBERT, R.F. Testing cement:sand screeds using the BRE screed tester. Slough (now Crowthorne), Cement & Concrete Association (now British Cement Association), 1986. 8pp. Publication 48.057.

PYE, P.W. BRE Screed Tester Classification of screeds, sampling and acceptance limits. Garston. Building Research Establishment. 1984. 4pp. Information Paper IP 11/84.

BRITISH STANDARDS INSTITUTION. BS 8203: Code of practice for installation of sheet and tile flooring. London, 1987. 27pp. (Currently under revision).

CHAPLIN, R.G. Floor levelling screeds. Crowthorne, British Cement Association, 1997. 16pp. Publication 48.061.

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