Working with natural stone - protection/maintenance

Modern grouts are often polymermodified 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 refered 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 absorbsion 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.

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.

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.

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.