I-Stone  Training Course

Quality of Stone Products and Maintenance in construction application.

Types of Stones
Stone properties
Stone applications
Stone Cleaning

Stone Applications > Indoor Applications

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 maintenance.

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.

Figure 6 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

Mode of placing

Amount of water (L/mē)

Traditional placing (mortar bed)

5 - 7

Placing in fresh screed

10 - 13

Placing with cementitious adhesive on hardened screed

0,7 – 1

3. Tablets
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.