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Weber Saint-Gobain - Official website of the company

Working with natural stone – protection/maintenance

Natural stone tiles can be very porous or textured and because of this require careful preparation prior to grouting to stop damage occurring. Once in service, natural stone will also need regular maintenance to keep it looking in top condition.

Problem

1. Tiles may be susceptible to staining

Modern grouts are often polymer-modified and can be very fine. Although this offers many benefits, such as better flexibility and increased strength, it can also mean they are harder to remove from tiles and more likely to stain natural stone.

'Picture framing' or 'Tram lining', as it is often referred to, is a description used when cement film has dried around the surface edge of a tile. The main causes for this are:

 • point grouting into the joints rather than slurry grouting the whole tile

 • leaving excess grout on the tile for longer than recommended by the manufacturer, causing a chemical etch due to the pH level of the cement

 • capillary absorption from porous stone drawing the grout into the surface

 • excessive water being used in the grout

These problems are more likely to happen if the stone is not prepared correctly with an impregnating sealant prior to grouting. Textured or porous natural stone are particularly susceptible to these problems.

If 'Picture framing' does takes place, it is very difficult and expensive to remove. A specialist refurbishment company will be needed to grind the stone and in most cases it is more cost effective to replace the tiles.

2. Grout and stone could stain when in service

When the grout and tiles have been in service, they can be prone to staining if they have not been finished correctly. The tiles should be adequately protected prior to being put into service.

3. Without maintenance, tiles can lose their effectiveness

Regular use and/or a general build up of grime can mean that natural stone loses it 'wow' factor. With careful cleaning and maintenance the natural beauty of stone can be kept for many years with only the minimum of expense. The use of the wrong cleaners can lead to a soft waxy build up or, even worse, damage to the surface of the stone.

Solution

Use the correct techniques for protecting and increasing the life

 

 

It is necessary to use not only the correct materials but also the correct techniques to protect, enhance and maintain natural stone. If these techniques are not used, stone could be damaged or stained which would destroy the natural beauty and effect of the stone.

Stage 1: Cleaning prior to grouting

Prior to grouting, check tiles are clean and dry. If the tiles need to be cleaned to remove dust, dirt or footprints, a pH neutral cleaner must be used. This will remove the marks without damaging the surface of the stone. If there is a small amount of adhesive residue on the tiles, a specially formulated, higher pH cleaner may be needed.

Stage 2: Protection of the stone prior to grouting

Once the stone is clean, it needs to be prepared for grouting. The surface of natural stone can be very porous and textured and if it is not prepared correctly, can be stained during the grouting process. To aid the removal of grout and to reduce the chance of staining, a suitable natural stone impregnator should be applied to the surface of the stone using a roller or sponge. This should be worked into the surface slowly to maximise effectiveness and to minimise frothing. After 4-6 hours the tiles should be dry enough to grout.

Stage 3: Grouting

Grout should be applied liberally and worked across the whole surface of the tile, not just along the joints. This will help minimise the 'picture framing' effect that is achieved when point grouting. Excess grout should be removed from the surface of the tile within 5-10 minutes. If any excess grout is left on the tile surface, it should be removed with the help of a specially formulated, high pH cleaner.

Stage 4: Final protection of the grout and stone

Once the grout is completely dry, preferably left overnight, another coat of natural stone impregnator should be applied over the tiles and grout. This should be repeated until all the surfaces are saturated and do not absorb any more impregnator. Once the stone and grout has dried it will be resistant to staining and easy to clean.

Stage 5: Maintenance

For regular cleaning a neutral pH cleaner should be used. This will prevent long term damage to the stone, sealant and grout. A good quality cleaner will contain cleaning components and enhancing agents that will make the surface richer. Any cleaning products containing wax should not be used as they promote a build up of false layers that will spoil the floor's appearance in the long term.