| Main Topic | Flooring
Jura gray – result of the acid test: Limestone.
Photos: Herbert Fahrenkrog (Magna Naturstein)
Scratch test passed – the floor can be cleaned without after-treatment.
But only rarely is a cleaning service provider also a geologist,
a concrete technician or a ceramic engineer who recognizes the
materials and knows how to handle their peculiarities.
This is why tools exist that help practically anyone answer the
important questions. Exceptions to the rule always exist, of
course, but the following information is sufficient for handling
of all materials found.
Test 1: Cleaning or finishing?
33Cleaning is the removal of dirt.
33Finishing is the deliberate application of some sort of treament.
Due to missing or incorrect documents, it is not always clear how
a floor should be handled. Film-creating products such as soaps,
polymers, waxes and so on, leave a lubricating film on all hard
stone (granite, basalt etc.) and ceramics that often reduces the
slip-resistance with which the material left the factory. If water
is added, a dangerously slippery – and unattractive – surface can
develop. Soft stone such as marble, limestone, artificial stone or
coarse ceramic products like terracotta should be gently cleaned
to conceal the rapidly appearing traces of use.
The FRT guide states: “When using soap cleaners or stone soap,
so-called soap scum develops together with the water hardness.
These are usually insoluble and slowly penetrate the pores of soft
stone or cling to their surface. This superficial scum can then be
mechanically compacted and polished. Over time, a matte shine
and light protective film develops. If necessary, the film can be
relatively easily removed with a suitable basic cleaner.”
However, there are also treatment products that can no longer be
removed with aqueous solutions. Who hasn’t run across intensive
shine products in the consumer area? Such aqueous polyacrylates
are also used in professional work. If cleaning service providers
are faced with floorings treated with this type of product, they
need to work together with the client to find professional help for
To find out whether a floor needs special care not, a scratch test
is used. A cutter or carpet knife is all that is required for this
fast, simple test. With light pressure, the service provider tries
to scratch the floor in an inconspicuous spot (e.g. not below a
If no scratches are visible or palpable, the material
only needs cleaning. On the other hand, if the scratches are visible,
the material can be cleaned and finished. The important thing
is not mistaking metal abrasion from the knife for a scratch.
generally leads to a deeper, more desirable hue.
Test 2: Acidic or non-acidic cleaning?
Cement residue can be removed either mechanically, using
or chemically using an acid. The scratch hardness,
says nothing about acid resistance. Even some very
hard basanites react to acids. Every acid also has preferences
this was discussed in a previous article
rationell reinigen 4.2005, page 34).
The acid resistance of mineral materials is tested with
acid, the standard acid used in building cleaning.
An eyedropper with undiluted amidosulfonic acid is used to apply
one drop on an inconspicuous spot on the floor. If it foams, grime
can only be removed mechanically from the water or cement
Be aware, however, that some stone does not foam, but
reacts by changing color! This is why the spot must be thoroughly
rinsed and dried. Critical materials include green serpentinite or
black basanite, which is often incorrectly designated as basalt.
The guide also points out that removing cement residue is an
service that must be carried out by the floor layer – not
part of final construction cleaning.
Test 3: Is there a damaged “dirt polish”?
The slip test is a practical method that clarifies many problems.
Everybody has seen the following at one time or another: Rub marks
from washers on ceramic or granite; water spots on black basalt or
fine stoneware; granite that has been dulled from amidosulfonic
acid. The common cause of these is ‘dirt polish’ that is damaged.
‘Dirt polish’ refers to hardeners spread during cleaning.
residues – which can remain after any cleaning
process – adhere
16 GLOBAL CLEANING | ISSUE 2017