What are the applications of natural stone?
Natural stone is a unique building material that can be customized for use in widely different applications. Whereas many building materials can only be used for one specific application, natural stone is so versatile that it can be used almost everywhere. As such, there is no need to look for different materials, natural stone fits perfectly into any environment.
- Floors and sideboards
- Wall cladding, dry space
- Kitchen tops and tables
- Vanity tops
- Door sills
- Massive (washbasins, shower bases)
- Wall cladding, wet space
- Coping stones for pools (no overflow)
- Decorative arts
- Patios, driveways, door sills, , base stones
- Vertically protruding parts
- window sills, covering stones
- window frames, door frames, glued facade cladding
- ventilated facade cladding
- Coping stones for pools
- Garden, decorative arts
- Spatial planning, urbanism
- Burial stones
Why choose natural stone?
Few materials have the longevity of natural stone. It lasts forever and can be recycled time and time again in new applications. Natural stone is a very sustainable product that does not produce any waste. When choosing natural stone, it is important to think about where and how you will use it. There is an application for every stone. The art lies in using the right kind of stone, with the right finish, in the right place.
Why are some natural stones more expensive than others?
There are different considerations when choosing a specific type of natural stone, and price is of course an essential one. Natural stone, however, is unique in that a lower price does not necessarily mean lower quality. Indeed, prices are mainly affected by the amount of labor to extract the stones from the quarry and the selection that is made afterwards. As such, a more expensive stone is not necessarily sturdier or better than a less expensive one.
What is meant by the quality of natural stone?
In the quarry, stones are often sorted by ‘quality’. Different people may however have different views of what quality means is in any particular circumstance. Certain features, such as a particular veining pattern, a particular color or grain size are considered more desirable, and the selected stones usually sell for a higher price. This does not mean, however, that the intrinsic quality of these stones is better. It is important that the customer is made aware of the differences, in order to make the perfect choice for his specific application.
I saw a natural stone with lots of color variations.
Colour variations are an essential feature of natural stone, and they are part of what makes stone such a unique material. Sometimes, stones of very different texture and colour are sold together. Sometimes, the quarry sorts the stones by colour. Jura stone, for instance, is sold as Yellow Jura, Blue-grey Jura or Mixed Jura, with both yellow and blue-grey tones. Slates and limestone are equally subject to colour variations. Even if some natural stones are heterogeneous, it is important to mix.
How come that natural stones have veins?
Veining in natural stones is due to deformations at the time the stone was formed. Where the particles did not fully stick together, gaps formed that were later filled due to water infiltration and calcification. Sometimes, these veins are actually stronger than the rest of the stone. Where the gaps did not fill, natural hairline cracks were formed.
I saw I stone I liked, but it has veins and cracks. What should I do?
As you can read in the product data sheets, we advise you to factor in 10 to 15% of breakage loss for some stones with natural cracks, as they may break during flooring. As such, you have to add 10 to 15% to the calculated floor surface. Obviously, this means that your cost increases by 10 to 15%, too. Sometimes, the quarry decides not to sell stones that have cracks. Because of the lower productivity, the quarry will however raise the prices of the stones they do sell, often by more than 15%. Thus, a lower sales price compensates for the higher breakage loss. That is why the consumer cannot ask the supplier to sort the stones and put aside the cracked ones. Do not worry about stones breaking later on, once the stone is in place it will not break and will last forever, on the condition that the flooring was expertly done. The same is true for stones with veining and hairline cracks. They are a typical feature of the stone and cannot be avoided.
My natural stone has variations in color or structure
Natural stone always displays slight variations in color and structure. Whether or not you consider these to be a problem, is a matter of personal taste. When choosing a natural stone, you should be informed about possible variations. We recommend visiting a showroom where you can see a real-life application of natural stone. Just a few tiles in a display are simply not enough to give you an idea of what the final result will look like. If you are looking for an exterior floor application, do take a look at the exterior show area, so you can see what the stone looks like when used for that very purpose.
Can I pick my own natural stone?
For most custom applications, it is perfectly possible to pick your own sheet of stone, at the sawmill or the sawmill’s supplier. If you are looking for a kitchen top, for instance, it is OK to make your choice by picking the sheet you like. Do take into account however that differences in lighting may affect the final result. For example, if you use the stone in a vertical position, the angle of light is also different. Your specialist retailer will be happy to advise you.
The natural stone I bought is different from the one I saw
Avoid choosing your natural stone by merely looking at a photograph or a flyer, unless you do not mind that the product will not necessarily look exactly the same. Visit a showroom where you can see different applications of the stone you like, or ask friends or family about their experiences with the stone. Even then, the newly laid stone will probably look different from the one you saw in the showroom. Indeed, the stone in the showroom has been used and cleaned, and has already formed a patina.
My floor has different color blocks
When flooring, the floorer will mix different crates of natural stone. This is a practice that is also commonly applied when installing bathroom tiles, bricks or wood. Make sure that your flooring installer knows what you want. He is not necessarily aware of the effect you are after and will simply lay the floor in accordance with industry practices.
My supplier does not have enough stock, what are the consequences?
Because you need to mix tiles when flooring, it is best to order the entire quantity you need in one go. If this is not possible, we advise you to first finish one room, preferably one that is separated from the other locations. Some stones are much more prone to color differences than others.
How much reserve do I need to factor in?
Always order some extra tiles. Accidents may happen and you may need to do small repairs. Measure the surface to be floored as accurately as you can to determine how many extra tiles you need. If the tiles are large or the surface to be covered is small, the cutting loss will be proportionally higher and you will need more reserve. Please be aware that if you have to replace tiles once your natural stone has already formed a patina, the color of the new tiles will be different.
What is the 5 percent rule?
Tiles sometimes break or get damaged during packaging, transport and installation. This does not mean that these tiles cannot be used. Tiles with broken corners or that look slightly different (veining, structure, flaking) can be cut and used near the wall, or in a spot that is covered by furniture. The 5% rule is the percentage that can be used in such a manner. Please discuss this thoroughly with your floorer. If not, it may well be that he puts the tile that you find the least attractive in the middle of the room. As this is purely a matter of taste, you cannot demand that the floorer replaces the tile.
My natural stone has changed color
Although we are usually not aware of it, the color of natural stone changes slightly with time. We only notice it when we remove a piece of furniture, for example. The reason is that natural stone is a living product, it gradually forms a patina when you use and clean it. The color difference is completely normal.
Exterior floors and façades also form a patina. Furthermore, they are exposed to sunlight (UV) and acid rain. If part of your terrace, driveway or façade is in the shade and another part is not, the part that is more subject to the elements may change color more quickly. It depends on the type of stone when the discoloring starts showing, and how important it is. Some stones may become lighter, others darker.
What is patina?
Patina is a natural protective layer that forms over time. It is a distinctive feature of many natural products. Soap, dirt and water are the main ingredients. That also means that some dirt on your stone floor is not a cause for alarm. Usually, and especially inside, the stone gets darker.
There are stains on my natural stone
Stains in natural stone are a popular topic of discussion. Stains have a negative sound to them. When choosing your natural stone, please remember that each stone has particularities, such as mineral concentrations, that are sometimes mistakenly called stains. These are an essential and inherent feature of the stone. Other stains are accidental, for example the discoloring that occurs due to acids on limestone. It is important to find out the origin of the stain. Some stains cannot be removed, instead they become ingrained and help to form the patina, which will give the stone its final look. Indeed, if you use limestone, it is good to know that it is nearly impossible to avoid stains altogether. Grease stains disappear in time, by cleaning the stone regularly with normal soap. It may take a while, especially for interior applications. A last category of stains are the ones due to inappropriate use, or a bad choice of stone for your application. For more information, please consult our ‘stain list’.
Some common stains:
White saltpeter veils. Caused by humidity, they disappear naturally after a few weeks. Make sure the floor can dry out, by only cleaning with a damp cloth and by rubbing it dry afterwards – as described in the maintenance instructions. Never cover the floor with a non-permeable material such as plastic sheeting. It is better to use breathable materials (such as Permafix).
Dark and dull stains:
After installation, the moisture in the soil migrates to the surface. The golden rule is not to start grouting before the surface has dried completely. If not, the sides of the tile may turn darker, and dark spots may appear in the middle. Make sure the tiles can dry completely. After some time, stains will disappear and your floor will become uniform in color.
My natural stone is scratched
It is the hardness of the stone that determines whether it scratches easily. Previously, hardness was measured with the Mohs scale. Nowadays we use the definition in the standard, and the Capon test. If there is a lot of foot traffic, it is better to choose a harder stone. Scratches can never be avoided altogether : indeed, diamond is the only stone that is completely scratch-free. Polished limestone is very prone to scratches, which nevertheless disappear automatically as the patina forms. Scratches will certainly not affect the value of your stone floor. Think of them like age wrinkles : they add character and charm to your natural stone.
What color of grouting should I use?
Grouts are a necessity, but they also have esthetical value. Especially for smaller surfaces, the color of the grouting has a major effect on the overall look of the floor. A dark tile with dark grouting looks completely different from that same tile with a light grouting. The mortar must necessarily have the same composition and consistency everywhere. Slightly less or more water can make for a different grout color. As such, please follow the instructions regarding the proportions, mixing times, waiting times, and processing times.
What grout width do I need to keep?
Our product data sheets include the recommended grout width for each type of natural stone. Sometimes, there are variations, for instance a grout width between 2 and 6 mm. How should you proceed in those cases?
If the sides of the sawed materials are perfectly square and smooth, you can use thin grout lines. If your natural stone has a coarse finish and/or coarse edges (tumbled or pitted surface) you need a larger grout line. Please get advice on the required grout width for your stone, with its specific finish, for your specific application. Your floorer will refuse if you ask him to install a tumbled surface floor with 2mm grouts. Conversely, it is a matter of personal taste if you want to have a grout of more than 6mm wide for your perfectly sawed tiles. As the dimensions of natural stone may vary very slightly, the grout width can compensate these variations in an esthetically sound manner.
The rule of thumb for grout width is the size difference in squareness + 2mm (+ 1mm for tolerances during installation or exterior applications).
Why is my natural stone not calibrated?
Calibrated means that the thickness of the stone is the same everywhere. Calibration is not possible for all natural stones, it is the manufacturer who decides. There is no calibration as regards the length and the width of the stone. Please get advice from your specialist retailer.
What size differences should I expect in natural stone?
As natural stone is a living and natural product, much depends on the type, the quarrying and the possibilities in production. The Technical Information 213 of the WTCB holds a description of the dimensional features for natural stones of the standard and marble type. Marble type are tiles sawed at the sawmill. At the mill, size tolerances can be kept under control. The standard type is a second type. But what with natural stone that does not belong to either type? You can of course use it, it is not bad stone, it is merely different (cf. ‘use of standards’)
What side and surface finishes are there to choose from?
The manufacturer decides what kind of finishes he wants to bring to market. Our wholesalers and the manufacturer may agree to sell different finishes of the same natural stone, if the market requires it.
Some common size finishes:
- Not faceted
- Hand tumbled
- Machine tumbled
Some common surface finishes:
- Naturally coarse
What sizes are there?
Every manufacturer and importer has a range of different materials, in different sizes. Please enquire with your specialist retailer or wholesaler what sizes are available.
Can I install floor heating if I have a stone floor?
Natural stone is ideal for floor heating. Its accumulating effect makes the stone store the heat. A low energy output means that the floor is always pleasantly warm. In summer, the same phenomenon makes for a pleasantly cool environment.
I have questions about the installation
In our section ‘Apllication’, you will find some basic instructions. Please always get advice on how to correctly install your chosen stone from your specialist retailer and floor installer. Always ensure the right aftercare. As the principal/owner, you are responsible for closing off the construction site. To cover the natural stone, use a product that is vapor-permeable. Your specialist retailer will be glad to answer all your questions.
My natural stone is damaged
By damage, we mean the impact of external factors : fire, falling objects, damage due to moving, etc. Most damages can be repaired. Sometimes, a few tiles need to be replaced. However, we no longer need to replace an entire floor. It is perfectly possible to restore the stone, at an affordable price.
What does it cost to restore or renovate natural stone
Nowadays, we have sophisticated techniques and companies specializing in the restoration and renovation of natural stone. The cost price depends on the type of damage and the type of stone. It is however a fraction of what it would cost to replace the entire floor. It is no small feat to restore the original look of the stone, especially because older floors have already formed patina. The specialist will try to imitate the look of the original.
In case the tiles need to be replaced and the floor needs to be regrouted, the result will look somewhat different. Indeed, the transitions between the edges of the tiles and the grouts are continuous, because the stone has been reground. Today, it is even possible to reground the stone very locally.
Can I install natural stone on an existing floor?
As long as you use the right technique, this is perfectly possible. Ask a specialized flooring installer to assist you. He will be able to tell you what kind of tiles you need and what is possible, taking the subfloor into account.
I heard that cleaning natural stone is problematic
That is simply not true. It is very easy to clean natural stone, on the condition that you have chosen the right stone for your application, and that you use a proper cleaning technique. Patina is the natural protective layer of natural stone. Regular cleaning with just a little bit of water and the right soap will provide nourishment for the stone. Once the stone has been sufficiently nourished (the amount of soap depends on the porosity of the stone), you can reduce the amount of soap. Make sure not to use too much soap, as this will leave a greasy layer on your floor. Too little soap is better than too much. Also, think about whether you are willing to clean the stone often. Do not put a porous stone that is highly subject to stains on your kitchen floor if you do not want to clean it often. There is definitely a stone to fit your individual needs and budget.
What is the best way to maintain natural stone?
Get advice from specialists in laying and maintaining natural stone, and do not forget these basic rules.
Always use the same product.
Use only professional products. You can find them on our partner page.
Do not panic if you see an unexpected stain. (you may have simply made the wrong choice)
Do not use too much water.
All purpose-cleaners are likely to contain acids. Never use it on limestone.
Use the natural stone, walk on it, and live on it.
Exterior applications often require less or no maintenance. As the stone is subject to the elements, sealers and color enhancers have no lasting effect. We recommend that you choose a low-maintenance type of stone, and just let nature run its course. In time, the stone will acquire its natural look. All exterior floors may turn green during winter and when they are in the shade. Green bloom on natural stone can very easily be removed.
When is natural stone frost-resistant?
Most granites are frost-resistant. However, it would not be wise to generalize. Frost-resistance can be scientifically proven using a standardized experimental set-up. During the test, samples of natural stone are put into a freezer, then defrosted, then analyzed by means of an audio test and a visual assessment. Each cycle lasts for 1 day and is called the frost-defrost cycle. In Belgium and the Netherlands, a stone is considered to be frost-resistant if it lasts through 168 cycles. In a regular year, there are often no more than 1 to 3 frost-defrost cycles. The cycle is more important than the actual temperature. After a frosty night, the temperature may rise above freezing point during the day, and go back to subzero the next night. Each time the temperature rises, the melt water fills the pores of the stone. When the water freezes, it expands. This expansion may cause damage to the stone, and the test measures the extent of the damage. Some types of stone that have passed the test are still not a good choice for exterior applications, for example because they are subject to discoloration. Please always consult the product data sheets. A bad installation can also cause frost damage, in such cases the cause of the problem is not related to the tile itself.
What kind of foundation do I need for my terrace/driveway/walkway?
Exterior flooring is mainly used to facilitate foot or car traffic. The thickness of the stone must be chosen depending on the use. Please ask your specialist retailer in what thicknesses the stone comes that you have chosen. As a rule of thumb, a thickness of 2.5 to 3 cm is required for foot traffic, and 4 to 5 cm for car traffic.
The next step is installing the foundation, which largely depends on the type of soil : sand, clay, peat, etc. As such, there are no general rules. It is the architect’s or the flooring installer’s responsibility to decide on the right foundation. An existing concrete slab that was installed when the house was built, cannot be used for a terrace, as it does not permit any excess water to drain off. There are of course solutions, such as installing a slope in epoxy with a drainage mat, or removing the concrete slab. Using the wrong foundation may have dire consequences.
How high should the drainage slope be?
The drainage of an exterior floor is essential. Even if the stone is perfectly frost-resistant, the thickness ideal, the soil and the foundation perfect, if the foundation slope is insufficient, damage to the floor is inevitable. The slope must be at least 1.5%. The ground should slope away from the building. The highest part of the terrace must be below the water discharge of the building. For tiles that are not entirely flat or have a rough finish, we recommend a minimum slope of 2%
What about expansion joints?
Apart from the regular grout width, the expansion of the floor, both inside and outside, must be reckoned with. Inside, the use of floating floors is quite common. A floating floor is a floor that does not need to be nailed or glued to the subfloor or the insulation. As such, the floor can and will move freely. In case of a small surface, the expansion joints absorb the tension. It is perfectly normal to see small cracks in the joints, or small gaps between the joint and the tile. It proves that the joints have done their job. If the cracks reach the tile itself, it means that there was too much tension. The cause may be insufficient expansion joints or an unstable subfloor. In old houses, enormous thresholds of 15cm thick and 40cm wide snap like a twig because they were too long and unable to absorb all the tension.
Where do I need expansion joints?
From experience, we know that for regular interior floors, one flexible joint is needed per 8m (length) and 50m² (surface). In case of floor heating, one per 7m and 40m². For exterior floors, the maximum values are 6m and 36m² for light-colored tiles and 5m and 25m² for dark-colored tiles. For patterned floors and floors where the grout touches the tile, the minimum values must always be complied with, notwithstanding the above rules.
What are standards?
The only rule that applies in a country, is the law. Standards, on the other hand, are documents that are written upon the request of the market, by experts in the field. Still, we often see that the professionals working in the field are not asked to give their point of view. Standards aim to translate regulations into a useful document. However, there are many more documents available that are more practically oriented and that are easier to use. Our product data sheets contain a wealth of information that cannot be found in any standard. It is the responsibility of the building specifier to refer to the documents that are relevant for his project.
Where can I file a complaint?