> Indoor Applications
For indoor applications, the durability of
the stone aspect is very important. The stone pathologies that can
appear are rather diverse. It can go from discolouration due to bad
cleaning to flaking due to expansive minerals in the stone itself.
Almost all pathologies are tricked by humidity. The quantity of water
that comes in contact with the natural stone has to be meticulously
followed up from the placement of the stone to the every day
1. Wall covering
For wall covering tiles, a thickness of more than 6 mm is generally
recommended. They are fixed to the foundation either mechanically or by
means of mortar or adhesives. If the stone is known to be susceptible to
stains a mortar consisting of white sand and low alkali cement (e.g.
white cement) is recommended. In bathrooms or other humid places, stone
types that have a low capillary absorption velocity and do not contain
swelling minerals/components have to be used.
2. Floors and stairs
According to EN 12058, floor tiles are flat natural stone elements with
a nominal thickness of more than 12 mm that are fixed on the foundation
by mortar, or another type of fixing agent.
The following four placing techniques are the most commonly used ones
for flooring units:
placing with mortar on a stabilised sand bed (Figure 6);
placing with mortar on hardened screed (Figure 7);
placing with cementitious adhesive on hardened screed (Figure 8);
placing in fresh screed.
Placing with mortar on a stabilized sand bed
Figure 7 Placing with
mortar on a hardened screed
Figure 8 Placing with
cementitious adhesive on hardened screed
The choice of the placing method depends
on the tile/slab dimensions and the levelness of the foundation. When
choosing the placing technique, one has to bear in mind that the amount
of water that eventually is transported through the stone tile is a
function of the placing method (Table 1).
Table 1 Amount of water, which can
be absorbed by the stone, in function of the placing mode
of water (L/mē)
placing (mortar bed)
5 - 7
10 - 13
with cementitious adhesive on hardened screed
Tablets are natural stone elements that are used as windowsills or
kitchen tablets. In this application, especially kitchen tablets,
external staining is an important issue to take into account. External
stains are here defined as stains that are induced by a reaction with
substances that appear by accident e.g. by spilling.