Blue limestone of Hainaut : question and answers.

Frequently asked questions - FAQ


Why choosing for the authentic Blue Limestone of Hainaut® ?

Only real blue limestone from Belgium is as resistant to wear and compression. It is impervious to water runoff, weather and temperature changes. These many qualities present in the natural stone make it unalterable. 100% 'made in Belgium', the Blue Limestone of Hainaut® is an ecological choice. Difficult to choose a more local sustainable material.

To learn more about the benefits of the Blue Limestone of Hainaut®

What is the difference between blue limestone and other, similar rocks or ceramic?

The authentic Belgian blue stone is a compact crinoid limestone, sedimentary in origin. Its non-porosity and density make it more resistant than other, imported stones of similar appearance. The oolites in Asian dolomitic stone, for example, oxidize with time and create unsightly rings. Foreign stones or imitation blue stone do not have neither the same sparkle nor the properties of blue limestone. Unlike them, the unpolished Belgian blue stone takes on a beautiful patina with age.

To learn more about the qualities of Blue Limestone of Hainaut®

How is authentic Blue Limestone of Hainaut® of a better quality than other stones of similar appearance?

The Blue limestone of Hainaut® is a compact limestone, which spent 345 million years as part of the very bedrock underneath us. Non-porous and highly resistant to wear and compression it is impervious to water runoff, bad weather and temperature changes. Adapted to our harsh climate, the Belgian stone can withstand repetitive periods of freezing and thawing. Its many qualities, present in its natural form, make it an unalterable stone and unmatched durability.

The entire operation of the Blue Limestone of Hainaut® is approved by the technical certificate issued by the Belgian Union for Technical Approval in Construction (ATG). The quality standards at Carrières du Hainaut® exceed European requirements. The statements of performance (EC) for finished products are available on request.

To learn more about the qualities of Blue Limestone of Hainaut®


How can one distinguish the true Blue Limestone of Hainaut® from imitations or foreign stones?

3 simple tips to ensure the authenticity of the stone:

The authentic fossils

The visible presence of fossilized crinoids gives Blue Limestone Hainaut® its incomparable character and charm and is proof of the authenticity of this local stone, which is far more resistant than any other stones of similar appearance. The Asian dolomitic rocks have no fossils, but they do have oolites that oxidize over time. Look closely, touch and compare. The authenticity of formerly living organisms makes all the difference.

Tip: Soak the stone in water. If it shows rings or brownish zones of a different shade, it is dolomitic stone, most of the time from Asia.

Certificate of origin

Carrières du Hainaut® guarantees the provenance and the absolute quality of each of their (half-) finished products with a certificate of origin - issued on purchase, and validated by a unique code and punch-mark.

Selected distributor network

Carrières du Hainaut® relies strongly on a network of professionals, which include a large number of stone and marble masons whose professionalism and know-how second to none. Ask for their advice, and allow yourself to be guided by the professionals identified and recommended by the ‘Carrières du Hainaut’®.


Certificates of authenticity

Les Carrières du Hainaut® assurent la provenance et la qualité absolue de chacun de leurs produits finis par la délivrance d’une attestation d’origine - délivrée à l’achat de ceux-ci - et, validée par un code et un poinçon uniques. 

Network of distributors

Les Carrières du Hainaut® s’appuient sur un réseau de professionnels composés majoritairement de tailleurs de pierres et de marbriers au savoir-faire remarquable. Demandez-leur conseil et laissez-vous guider par les professionnels identifiés ‘Carrières du Hainaut®’.

Trouvez un distributeur proche de chez vous


Where can I buy Blue Limestone of Hainaut®?

Carrières du Hainaut® relies on a network of professionals - stonecutters and masons – who are passionate about natural stone, and have an extraordinary artisanal expertise. These professionals both sell the Carrières du Hainaut® finished product and transform our stone into decorative shapes and elements according to their clients’ wishes. Ask for their advice on how to give life to your project.

Find a dealer near you 

How can I be sure that a dealer is selling the authentic blue limestone from Carrières du Hainaut®?

Some retailers clearly identify the blue limestone from Carrières du Hainaut® by presenting it in our own display units. These distributors, who are equipped to present the complete range, are identified as key distributors, while other stone masons also offer our stone and the same quality of service. If in doubt, you can always ask your distributor for the Carrières du Hainaut® certificate of origin. To learn how to recognize the Blue Limestone of Hainaut®, see 'How can one distinguish the true Blue Limestone of Hainaut® from imitations or foreign stones?in this FAQ.

Find an official distributor nearest you.

Where can I find a worktop, a table, a bench, or other custom-made pieces?

Your natural stone professional, or stonecutters or masons is the person to speak to about custom pieces. They alone have the expertise and know-how needed to work blue limestone. Whether you need a bench, a table, a shower, a basin or a vanity unit ... your stonemason is where you’ll find the passion and inspiration you need to give life to your project.

Find a dealer near you 

Where do I find crushed stone, or other aggregates?

Carrières du Hainaut® only puts on the market matter meeting the most stringent standards for constructive and decorative applications. The crushed stone, a by-product of the stone quarried on our site, is processed locally by our specialist external partner Holcim. Contact Holcim for more information, or check with your building materials distributor.

And where can I find gabions (wire boxes filled with stone)?

Building materials distributors generally sell this product either ready-filled or to be filled once laid. Two options are available: a gabion filled with crushed stones or filled with BrickEno® neatly placed side by side, giving a very orderly effect and ideal for use in landscaping.


Can one use soap to clean and maintain blue limestone?

It is perfectly alright to use soap to maintain your blue limestone, though regular cleaning with clear water should be enough. Every third clean, use slightly soapy water to clean your blue limestone. Avoid using too much soap. It doesn’t clean any more, and excess soap risks leaving unsightly marks on the surface of the stone.

Learn more about the maintenance of blue limestone

What is the best soap to use?

If you want to use soap when cleaning, choose a neutral pH soap, such as Marseilles soap flakes, or Carolin ... avoid maintenance with acids, chemicals or descaling agents for sanitary use! The blue limestone is a compact limestone and therefore reacts badly to descaling agents.

For outside use, regular maintenance is not in itself necessary - the weather will take care of that for you. Once a year you should remove vegetation build-up after the winter with water and bleach, or with a product from the Lithofin range.

If you use a natural stone cleaner, take care to follow the manufacturer's instructions.  Measure out the product correctly and test it first on a hidden part of the stone.

Learn more about the maintenance of the Blue Limestone of Hainaut® 

There’s a white veil or film on the surface of my blue limestone. What should I do?

If you’ve used too much soap in cleaning, a white film, rings or cloudy traces may appear on the surface of the stone. Relax! All you have to do is clean the limestone a couple of times with clear water. For a thorough cleaning, add baking soda to the bucket of water or use a multi-cleaner product for natural stone (Lithofin).

Learn more about the maintenance of the Blue Limestone of Hainaut®

How do I protect my blue limestone?

The hardness and non-porosity of blue limestone naturally protects against external aggression. Everyday accidents may leave traces of surface but they never will penetrate the stone and, with time they fade into the patina. Blue limestone is a natural living material – don’t be afraid if it gets a couple of marks or scratches! It’ll only gain in character and charm.

A simple cleaning with soap (in moderation) nourishes the stone, helps protect and blurs any micro-scratches. Caution: Avoid using too much soap. An excess of soap can create an unsightly film on the surface of the stone.

If you want to apply additional protection to your worktop or to your patio, for example, chose protection products that are produced specifically for natural stone, such as Lithofin. Or use the traditional method, which is to coat the stone with a linseed oil and turpentine solution.

Learn more about how to protect the Blue Limestone of Hainaut® 

How can I speed up the patina effect on my stone?

Blue limestone is a natural and living stone, it evolves and develops a patina over time. Think of churches and castles of centuries past. Regular cleaning with soap will effectively darken the stone and accelerate the patina effect. Caution: Avoid using too much soap. An excess of soap can create an unsightly film on the surface of the stone. (See ‘There’s a white veil on my stone' in this FAQ ).

Learn more about the maintenance of the Blue Limestone of Hainaut® 

And how can I slow down the patina effect on my stone?

If you want to let time do its work naturally on your stone’s patina, you can slow down the effect with regular washing with soap, with plain water or with a little bit of ammonia or baking soda.

Learn more about the maintenance of the Blue Limestone of Hainaut® 

Can I wax my blue limestone floor?

Carrières du Hainaut® advises against waxing your blue limestone floor – a waxed surface shows up scratches and marks more than a non-waxed one. 

Can I use rock salt for melting winter ice on my blue limestone paving?

Blue Limestone of Hainaut® can take anything. Once the weather has thawed, rinse off the salt with clear water.

Is it possible to restore blue limestone?

If you’re renovating an old building and would like preserve the authentic parts in blue limestone you should first call a professional stone mason for an appraisal on how to re-cut and revive your stone. You’ll find a choice of top quality artisanal masons in our list of distributors.

If you’re the unhappy victim of vandalism and your facade is covered in graffiti don’t worry – there are many natural stone renovation services that can achieve miracles, including, for example, Stone Attitude (, App All Remove (

What about black stains that appear on my stone?

From time to time black spots may appear on the surface of your tiles, and small splinters may break off occasionally. This superficial flaking phenomenon is inherent in all limestone and presents no danger to the durability of your flooring. If you look at the paving of older buildings, you’ll see this effect regularly, even if it is less visible thanks to the patina of the stone. 

Tegels uitbreken en een nieuwe vloer leggen

Is het altijd nodig om eerst de oude tegels uit te breken?

Hier geldt de regel: bezint eer ge begint. In veel gevallen is je oude tegels uitbreken namelijk niet de beste optie. Soms is het bijvoorbeeld beter om je nieuwe vloer bovenop de oude te leggen.

Hoe ga ik te werk om mijn vloer uit te breken?

Dat hangt af van het type vloer. Een oude tegelvloer die op zand of zavel ligt, is bijvoorbeeld makkelijk uit te breken met een koevoet of een drilboor. Breek de vloer in kleine stukken uit, zodat je ze met een kruiwagen kunt vervoeren. Maar weet ook dat een vloer uitbreken en een nieuwe leggen flink wat tijd in beslag neemt en heel wat rommel en stof met zich meebrengt. Wees dus realistisch en plan genoeg tijd in voor de werken én de schoonmaak achteraf.

Moet de ondergrond perfect egaal zijn voor ik begin?

Ja, als je je oude tegels hebt uitgebroken, is het cruciaal dat de ondergrond helemaal egaal is voor je de nieuwe vloer legt. Mogelijk moet je de chapelaag dus opnieuw egaliseren. Hou er rekening mee dat zo’n laag – afhankelijk van de dikte – enkele weken moet drogen. Reken ongeveer tien dagen per centimeter en twee weken per centimeter als de chapelaag dikker is dan acht centimeter.

Hoe dik moeten mijn nieuwe tegels zijn?

Bij een verbouwing zorgt een te dikke vloer vaak voor problemen. Zo moet je de ondergrond misschien uitgraven of de deurhoogte aanpassen om de vloer te laten passen. Het is dus altijd beter om een dunne vloer te kiezen. Ben je op zoek naar een kwaliteitsvolle vloer die toch niet te veel plaats inneemt? Dan zijn de dunne tegels van Carrières du Hainaut de ideale kandidaat. Onze tegels zijn maar 15 millimeter dik, waardoor ze erg makkelijk te plaatsen zijn. Bovendien zijn ze verkrijgbaar in een brede waaier aan afwerkingen en formaten. Zo kun je alsnog een dunne vloer leggen, zonder in te boeten op kwaliteit en karakter!


Choosing a finish

Each finish gives the stone a different shade, so combinations of finishes create new harmonies. While the choice of finish is mainly an aesthetic one certain technical limits have to be observed. Thus, in order to make the right choice, take into account the application intended and the ideal thickness recommended.

Interior - while both dark and light finished are equally suitable, it’s handy to remember that the stone will always darken over time – a patina that becomes more and more beautiful as the years go by. For the exterior, we recommend a preference for lighter tones – this way neither the sun nor the elements will affect the look of your stone.

For your floor coverings  in wetter areas, or in frequently used passages, use slightly structured finishes such as Blue Flamed, EnoSkin®, EnoStyl® … Not only are they aesthetically pleasing, but above all, their anti-skid surface offers total security, while at the same time total comfort when walking barefoot.

A Polished finish is to be avoided for floors, but can be ideal for interior walls where its polished aspect will shine.

Roughly textured finished such as Chiselled, Charred, Sclyped, Old-Cut, Pick-Dressed or Dimpled, with their highly decorative effect, are perfect for mural applications. It’s important to be aware of the minimum thickness necessary for these finishes and, if necessary, to preview the correct fixing system. These finishes are equally adapted to floor coverings, but here it is recommended to use them in areas where one wears shoes.

Discover the Blue Limestone of Hainaut® range of finishes

What thickness should be used in interior application?

The laying technique depends on the application and the surface on which the blue limestone is to be placed. This has an influence on both the thickness and format used. For flooring, if you are renovating a floor, check the state of the screed, its flatness and cover, as well as the space available under doors, whether or not underground heating is installed etc.

For wall application, the thinner tiles are much easier to install. For thicker ones, specific techniques are to be used. For worktops, furniture and other decorative elements, the thickness is a matter for you and the person making the piece or installation to decide between you, according to your aesthetic and technical criteria.

Carrières du Hainaut® has specially developed the DUENO range for interior applications. This range of thin tiles (15 mm) works just as well for flooring as for wall decoration, for new projects and for renovation projects.

Discover all the application possibilities of Blue Limestone of Hainaut®

Can blue limestone be used around a swimming pool?

Water simply pearls on the surface of Blue Limestone of Hainaut® - its non-porosity acts as a natural shield. Hardly surprising as blue limestone was originally laid down deep underwater, hundreds of millions of years ago when our region was at the bottom of a tropical ocean.

For your swimming pool surrounds and submerged steps, choose a lightly textured finish, such as Blue Flamed blue, EnoSkin®, or EnoStyl®… They’re anti-slip, and soft and comfortable to walk on.

Discover some examples of blue limestone pools  


What thickness should be used in exterior application?

Placement technique depends on the application and the surface on which the blue limestone is to be placed. This has an influence on both the thickness and format used. Where you live is also an important consideration. For facades in Belgium, the official standard is 3 cm minimum. In France and in the Netherlands, 2 cm is sufficient.

For underfoot use (paving or flagstones) the minimum thickness varies according to the intended use. If the paving is ornamental, or if it’s intended solely for walking on, 3 cm is sufficient. For your private garage driveway, 5 cm to 8 cm should be used, with the latter especially recommended for car pathways or parking or stopping areas for delivery vans or other heavier vehicles.

For more decorative elements such as windowsills, door surrounds of wall skirtings, aesthetic criteria will also have to be taken into account. Ask your professional mason or the person responsible for the works to help you decide on the thickness to be used according to aesthetic and technical criteria, as well as the official standards in use.

Discover all the application possibilities of Blue Limestone of Hainaut®  

Does blue limestone suffer from ice or extreme cold?

Authentic Belgian blue stone is compact and non-porous. Water simply doesn’t penetrate the surface. This intrinsic quality makes it unalterable and unaffected by temperature swings or repetitive periods of freezing and thawing.

Can blue limestone be used for a fireplace or a barbecue?

The real Blue Limestone of Hainaut® is perfectly at home beside the fire. Highly heat resistant, it adds a touch of nobility to your fireplace. However, it is recommended not to place it in direct contact with the flames.

Discover all the application possibilities of Blue Limestone of Hainaut®