How to fix natural stones

Solution datasheet

Common issues and queries you can face

Different types of stones

Limestones, granite, marble, slates…Each type of natural stones has its own technical or aesthetical characteristics, and their composition can vary drastically when compared to standard ceramic tiles.

Fixing stones thus requires special care and special application methods.

Identification of the stones installed is essential to for proper preparation and application.

Artificial/reconstituted stones however, have different composition and require adapted application techniques and special tile adhesive products (fast-setting adhesives,...etc).

Not all natural stones have same characteristics

Mechanical characteristics, hardness and cohesiveness of natural stones can differ a lot. Thus, natural stones are not regulated in terms of porosity and movement.

Sandstone and limestone will be porous. Granite and marble will be quite dense, slate could warp.

Tile adhesive and stones

Some light-colored natural stones require special care when fixing them.

Stains and different shades are a frequent phenomenon that appear when fixing light-colored natural stones (especially limestone/marble tiles). This can result from bad transfer of the tile adhesive between the substrate and the natural stone.

As well, if a grey adhesive is used, this can make the tile appear darker in shade once installed. (Alkalis contained in the cementitious adhesive can create a natural chemical reaction)

A spot-fixed method of application should not be used by tilers as it can result in shadows seen from the tile’s face where the adhesive is in contact. It also increases the likelihood of point load breakage.

Tiles may be susceptible to scratching

Same tile grouts can scratch soft glazed tiles (such as hand-made tiles) and the surface of soft stone (such as marble).

Step by step solution

weber solution

Substrate preparation

Substrate should be dry and free from dust or any traces of old materials that could impede a good adhesion with the stones.

In case of tiling over existing tiles or coatings, check their adherence and repair any hollow areas or replace de-bonded tiles.

In case of a very porous substrate (a water drop absorbed in less than a minute) or very smooth surface, apply the primer webercol prime using a brush or a roll.
Tile adhesive

Apply a white adhesive webercol flex, webercol max, webercol F1 or webercol fast using a suitable notched trowel, adapted to the size of the stones and the flatness of the substrate.

For large size stones and on substrates presenting defects in flatness, back-buttering is recommended (tile adhesive on the substrate and on the back of the stone).

Exert a strong pressure on the stones or use a rubber hammer to remove air and ensure a good transfer.

During application, carefully eliminate all traces of adhesive on the face of the stones with a wet sponge.
Stone grouting

Before grouting, wait at least 3 hours after application of webercol fast or webercol F1 (fast-setting adhesives) or at least 24 hours when using a normal setting adhesive.

We recommend weberepox easy for joint from 1.5 to 10mm and weberjoint perfect or weberjoint deco for joints between 1,5 and 20 mm.

The fineness of the grout particles reduces the risk of surface scratching the tile. weberjoint perfect is the right product to grout polished marble and any tiles with a soft surface.