Natural stone is being used both at home and in office buildings because it is a durable and visually attractive material that can serve you many years with the proper care and maintenance.
The beauty of natural stone is that it can be used for different purposes both indoors and outdoors and natural stone tiles for bathrooms, kitchens or countertops are gaining more and more popularity over concrete, ceramic and wood in recent years.
But don't let the word stone deceit you - it is also a delicate material that needs to be protected from scratches and stains and cleaned accordingly in order to prevent further damage. Below we will try to present you with all you need to know about cleaning and maintenance of natural stone in 5 simple steps. Follow them and your marble, granite, slate, limestone or travertine tiles will serve you for generations.
You should know your natural stone
In order to be able to properly clean and maintain your natural stone the first step is to be familiar with it and be able to correctly identify its current condition. Natural stone can be generally divided into two main groups depending on their composition: siliceous stone or calcareous stone.
It is very important to know to which type does your stone belong, since this will influence the method of surface cleaning that you should choose and can be critical when selecting the appropriate cleaning materials. The Marble Institute of America provides us with a simple definition of each type of stone and suggest an easy test, that you can perform at home in order to define if you have siliceous or calcareous stone, in case you are in doubt.
Siliceous stones are mostly made of silica (a group of minerals composed of silicon and oxygen) or quartz-like particles. The most common types used both as interior and exterior tiles include granite, slate, sandstone, quartzite, brownstone, and bluestone. Siliceous stones are considered more durable and easier to clean, since they are resistant to acidic liquids and cleaning products (meaning that if you spill some vinegar on your granite kitchen counter you won’t ruin it). However, since these stones can also contain small particles of minerals that are vulnerable to acid, it is still advisable to use powerful alkaline cleaners to avoid accidental damaging.
Calcareous stones are composed mainly of calcium carbonate, which can be found in shells and pearls, for example. The most common calcareous natural stones are marble, travertine, limestone, and onyx. This type of stones are more delicate and sensitive to both acidic and alkaline cleaning products, so make sure not to apply the substance you use for your granite countertop to your marble tiles.
If you are not sure, whether the natural stone used in your bathroom or kitchen is siliceous or calcareous, there is a simple acid sensitivity test that you can perform to verify its type. You will need 4 ounces of a 10% solution of muriatic acid or household vinegar and an eyedropper.
Choose carefully the area to perform the test, as it may permanently etch the stone - it’s better to choose the closet, if you have natural stone tiles there, or opt for the corner of the room. The spot should be away from any mortar joint, as well. Apply a few drops of the acidic solution to the stone at an area not larger than a coin and wait a few moments to see if there will be a reaction. If the drops start bubbling or fizzing, then this is a sign that the stone is reacting to the acid and is therefore calcareous. Make sure to wipe and wash the spot with water immediately to curb any further damages.
If there is insignificant or no reaction, then the stone is siliceous. In this case, you should also need to wipe and wash the area with water. Be advised that if the stone is sealed there can be no reaction even if it is siliceous and also be very careful when applying the muriatic acid and use proper hand and body protection as this is considered a hazardous material. If you believe that this acidic test is not for you to perform, then better consult a stone specialist who will be able to identify the exact type of natural stone you have at your home or office.
Assess your natural stone's current condition
Once you have identified the type of your natural stone you should perform a comprehensive assessment of its current condition, which will allow you to choose the most appropriate way for its cleaning and overall maintenance. A good and practical idea is to draw a checklist with questions that you can follow during your evaluation. The questions should be general and applicable to all natural stones regardless of their type or purpose. A good example features:
Are all tiles flat?
Are there any dents or cracks visible on the surface?
Are there any stains? If yes – what type (if possible to identify): from fats, paint, ink, etc.
Is there a stone coating with wax, acrylics, enhancers?
Is the stoned sealed or are there any signs that the topical sealer has worn off?
The answers will give you a good starting point on how to proceed further. Some solutions may require professional assistance – an uneven or cracked tile, for example, may need to be replaced, a worn off sealer re-applied, etc.
You can keep your improvised questionnaire for the next time or even land it to a friend who is wondering how to start the natural stone cleaning process.
Daily care and cleaning procedures
In this chapter you can find some practical advice on how to maintain your natural stone on a daily basis and thus avoid early wear and tear. If you have countertops made of natural stone that the general advice for both siliceous (granite) and calcareous (marble) stones is to put coasters under glasses, especially with juice or alcohol, never to place hot plates or pans directly from the oven onto the top, use trivets or mats under kitchenware and silverware to avoid scratching.
All type of stone countertops can be cleaned with warm water and a small amount of stone soap, which you can buy from natural stone selling stores, or simple mild dishwasher liquid. Rinse the surface well after washing it with the soap and dry with a soft cloth. Don't use lemon, vinegar or other acids on limestone, travertine and marble, as they will etch the stone and avoid using them with granite and slate to be on the safe side. Never use scouring powders or creams because their abrasive particles will scratch the surface of any natural stone.
If you have natural stone tiles on your floor you should be aware that they become slippery from wet and that they can be scratched by the debris on your shoe soles. Therefore, it is a good idea to place doormats or area rugs both outside and inside the premises, so people can dry and clean their shoes before stepping onto your natural stone flooring. An interesting fact is that it takes about 8 steps in order to remove any dirt or sand from your soles.
When it comes to the daily cleaning of your natural stone flooring you shall start with removing any dirt, dust, sand or other debris, since they are abrasive and will harm your stone. It is recommended to swipe them using broom or mop, however, all stone types can be vacuum cleaned too, and for slate and granite tiles that is even advisable. If possible use a glide attachment for your travertine tiles, as they get scratched easier than others. If you notice a scratch on your travertine floor you can use diamond polishing pad to remove it.
Once the debris is cleaned you can wash the floor using a soft mop or terrycloth towel and mild dishwashing detergent or stone soap. Be sure to dry the floor afterwards. Note that if there is a spill of water or any other liquid over a granite floor you shall blot it and not wipe it (as you would do with a carpet), as wiping will just drive the liquid into the small cracks of the stone.
How to remove different stains?
No matter how well you take care of your natural stone on a daily basis, it can get stained from time to time. Here are some tips on how to clean different stains, which will work on most types of stones.
Most stains can be cleaned by means of stain-removing poultices, which include materials like kaolin, powdered chalk, talc, white molding plaster, etc. A poultice can be made of white cotton balls or white paper towels. You can also buy a premixed substances to which only water is added and are ready to use. One pound of a ready poultice will cover approximately one square foot and it should be left on the stain from 1 hour up to 48 hours, depending on the stains, which can be:
Organic stains from tea, coffee, tobacco, food, etc. can be cleaned using 12% hydrogen peroxide (hair bleaching strength) and a few drops of ammonia. If your outdoor natural stone gets such stains it might be enough just to leave the sun and rain wash out the stain.
Oil stains may be caused by butter, tar, cooking oil or cosmetics. They will darken the stone and usually need to be chemically dissolved in order to be removed. You can prepare a poultice with acetone, ammonia or mild household detergent and then scrub gently to clean the stain. For marble tiles you can spread the surface with fine powder as whiting or cornstarch and leave it for 24 hours before scrubbing with hot water and a detergent solution.
Rust stains are orange or brown and usually have the form of the object that caused them, which can be a metal flowerpot, nails, cans, metal containers, etc. The best way to remove such stains is to use a poultice or a commercial rust remover. Be advised that if you leave the remover for a longer period it may etch the stone.
Ink stains are caused by markers or pens. You can use bleach or peroxide to clean light stones and lacquer thinner or acetone for darker stones. Again – do not apply the substance for a long period to avoid ruining the natural stone.
Paint stains, if smaller, can be scraped off very gently with a razor blade or by applying lacquer thinner. A commercial liquid paint stripper is needed if the stain is significant.
Etch marks – these are caused by acids from milk, alcohol, fruit juices mainly on calcareous stones, so be careful when placing your glass on the marble kitchen top. Any acidic spill should be wiped out immediately and then the surface must be cleaned with a wet cloth. If, however, the liquid has stayed longer on the natural stone, there might be deeper etching and you might need the services of a professional to polish it.
These are the main types of stains that can affect your natural stone. The overall rule is that the sooner the stain is removed, the better the result is.
Should you seal your natural stone?
Another important step for properly maintaining and keeping your natural stone clean is to seal the stone. You should take into account several factors such as the type and finish of the stone or its location before taking this step and even better consult a professional.
The Marble Institute of America recognizes that in some cases the stone is better protected and easier to clean and maintain on a daily basis if sealed, while in other the topical sealer may alter the surface or texture of the stone. Generally, it is not recommended to seal stone tiles that are used outside since the layer created by the sealer may retain moisture.
Interior natural stone tiles, however, are usually sealed to protect them against dirt and spills. Some of the companies installing the tiles may seal them too, however, you can do it yourself as well. If you have, say, travertine tiles, you need to sweep the floor very well with a soft push broom and then mop it with warm water. Be sure to dry it with a towel before sealing it. Then simply pour the stone sealer onto the travertine tiles and rub it into them gently using rags. Allow some time for the sealer to dry.
These are the main steps to follow when you have natural stone at home that you want to keep intact and as good as new for many days to come. All of the above can be summarized into 5 general Dos and Don'ts for your convenience:
Do clean floors with dust mops frequently.
Do clean countertop and floor surfaces with stone soap or mild household detergent.
Do rinse and dry the surface after washing.
Do blot spills rather then wipe them.
Do protect the surface of the natural stone counters with coasters or mats and floors with area rugs or door mats.
And
Don't use any acid liquid, including vinegar or lemon juice on calcareous natural stones such as marble, travertine, limestone.
Don't use scouring powder or other detergents that contain abrasive particles.
Don't use acid cleaning detergents, such as bathroom cleaners.
Don't use old or worn out vacuum cleaners, especially for travertine tiles.
Don't mix chemicals, especially bleach and ammonia as this combination is toxic.
