When it comes to sheer elegance, you would be hard pressed to find anything to compare with natural stone. It has been used for millennia as a building material, and can be found in some of the most prestigious buildings in the world.
Natural stone is commonly used as a flooring material and, when it is polished to a high gloss, it can be breathtakingly beautiful. Understanding the effects of erosion on the stone surface can help you develop a maintenance plan to meet the needs of the natural stone flooring in your building.
Soil, whether it is dirt, sand or micro-grit, can be damaging to any floor surface, and stone is no exception. Even though stone is very hard, silica minerals such as quartz, feldspar and mica can scratch the stone surface causing micro erosion. The tiny scratches dull the surface and create areas for dirt to collect.
Reducing the impact of the soil to the stone floor is the primary job of the floor maintenance technician, and identifying the soil entering the building helps to determine how to combat it. Keeping the soil out to begin with can be aided with a good walk-off mat program and should be incorporated in any facility, whether it has stone flooring or not.
Developing a maintenance program begins by identifying the type of stone you will be working on. Natural stone, like all flooring materials has properties and characteristics that contribute to the looks, durability, hardness and composition of the product.
Generally, there are several stones recognized as suitable for flooring material: granite; serpentine; marble; limestone; travertine; quartzite; slate and sandstone. There is also manufactured stone flooring made of 70% marble or granite chips in a 30% cement or resinous binder; these are called terrazzo and agglomerated floors.
The properties and characteristics are the determining factor of whether a stone can take a polish or not. The way the stone is formed can have an impact on its hardness. Slow-cooling igneous granite is very hard, while some sedimentary slate can be soft enough to scratch with a fingernail.
The scale for measuring a stones hardness or scratch resistance is called the Moh’s scale and runs from 1 to 10, with 1 being the softness of talc and 10 being the hardness of diamond.
The texture of the stone will also impact the development of the floor maintenance program. Basic textures associated with stone flooring include cleft surfaces – usually associated with slate and quartzite – as well as thermal cut or flame cut texture typically related to granite.
These textures are not achieved by polishing, but by different methods performed at the quarry or onsite. Stones that have a smooth but dull surface are referred to as a honed surface, while a highly reflective surface is described as a polished surface. Both are achieved using various diamond abrasives and, in many cases, polishing compounds.
Cleft irregular and thermal or flame cut surfaces are textured and can contribute to slip resistance, but they can be difficult to keep clean because the surface itself tends to be a soil collector. Soil entering a building will be displaced from the shoe and come in contact with the floor. The soil will then migrate to the lowest point, which may end up in the minute pores or recessed edges of the textured surface.
Once they settle, they become exceeding difficult to dislodge and build up over time causing the floor to look unsightly.
Honed flooring is not quite as bad in collecting soil as the previous surfaces, but it does collect soil in the pores and scratches. A honed floor looks dull by design, it is achieve by using course to medium grit diamond abrasives to hone the surface. Honed surfaces are smooth and even, just very little gloss.
The pores of the stone will collect soil and over a period of time begin to look dirty. Machine scrubbing with medium scrubbing pads or brushes, followed by extraction using a wet vacuum periodically will help to keep honed floors looking good.
Polished stone flooring can have excellent gloss and a highly reflective surface. Polished stone floors are achieved by using fine diamond abrasives to smooth the surface until the desired gloss level is achieved.
Highly polished floors do not collect soil in the pores as there are very little pores to collect in. Instead, the floor will begin to show a traffic pattern, which is caused by microscopic minerals in conjunction with moisture and foot traffic. The traffic patterns are usually maintained using a polishing compounds or just diamond abrasives on a periodic basis.
In some environments such as casinos and hotel lobbies, these procedures may be performed on a routine basis.
Regardless of the type of natural stone floor that is in your facility, the daily/routine maintenance is critical to keeping them looking good all the time. The soil that the matting system does not collect will be distributed throughout your building with the heaviest amount near the entrances.
Sweep, use a dust mop or cloth system, or vacuum these areas daily or, in some situations of heavy traffic, multiple times a day to reduce the amount that gets to the rest of the facility. Removing the dry soil before it becomes a problem will reduce erosion considerably.
Mopping is done when the dry service procedures are no longer effective to remove soil that has adhered to the floor. Use one of the wet mopping procedures in accordance with the soiling condition. Spot mop for spills, damp mop for light soil or wet mop when soil is moderate or heavy.
On honed surfaces aggressive mopping works very well. When aggressive mopping, use hot water and neutral or all-purpose cleaner diluted to manufacturers recommended dilution ratios.
Apply a liberal amount of solution to the stone floor and allow some dwell time to soften the soil and suspend it in the solution. Extract the contaminated solution using a wet vacuum and rinse the floor thoroughly.
Stone flooring is everywhere and, chances are, the floor maintenance technician will encounter them at some point. The stone floor, although rock hard, is no “magic bullet” against the effects of erosion.
Understanding the type of stone, the environmental soiling conditions and the foot traffic can be essential in developing a good floor maintenance program for your natural stone floor.