Slip and Abrasion Resistance values.
Slip resistance tests were originally developed
as a rubber pendulum test by the Greater
London Council, published in 1971. Today, a
4S pendulum test is recommended, with a 96
hardness rubber to simulate ordinary pedestrian
foot traffic for public areas and 55 hardness
rubber to simulate bare foot traffic - more suitable
for pool surrounds and wet bathroom floors. The
HSE expect a minimum value of 36 in the wet or
dry, as I suspect will you or your client’s insurance
company.
The surface finish will affect the test results – a
sandblasted face presenting the least potential for
slip and a highly polished floor the most. If there
is heavy footfall on the floor, even if it begins as
honed, it may end up as polished with time and
footfall.
Therefore, abrasion resistance test results will
help to understand the likely wear capability of
the floor. Results are expressed in mm and BRE
guidelines suggest anything under 23mm of wear
is suitable for intensive use, 23 to 30 medium use,
30 and above domestic use. You will need to
understand the predicted footfall to decide which
category your floor falls into.
Onyx slabs waiting to be cut.
Floor loading is another factor to consider.
Floors that are expected to carry the weight of
cars, for instance, will require a stone with a high
flexural strength and possibly thicker than you
would have expected, to carry the additional
load, however infrequent.
There are coatings on the market that claim to
improve a stone floors slip resistance. But always
check the on-going maintenance requirements and
costs and any warranty offered.
Flexural strength and slip resistance results can be
found on the CE marking certificate, which should
be obtained from the supplier of the stone. As
long as we are in the EU it is their responsibility to
provide this to the buyer. Abrasion resistance tests
do not have to be declared on the CE certificate
for external or internal floors, but I would suggest
these are checked before specifying the stone.
Then there is underfloor heating, sub floor
preparation, waterproofing and installing the
stone……..
Arabescato book-matched shower wall.
Stone is a fantastic product and elevates design
to a luxury level. Just make sure you do your
homework on the where the what and the how.
Robert Merry is a member of the Technical
Committee of the Stone Federation of Great
Britain. His company, The Stone Consultants,
are an independent stone consultancy who offer
advice and guidance on stone related issues
to the construction industry including technical
specifications and expert witness.
www.stoneconsultants.co.uk M:07771997621
E:[email protected]
Quarter book-matched marble floor.
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