Natural marble and cleaning soot

[bossofdos64]

We have a natural marble fireplace surround which has some soot stains (due to the flue not being completely open). It's on a vertical surface and the marble is a light beige.

We have tried a clean dry rag, water, dishwashing liquid, and stone soap. We have been afraid to try any of the marble cleaners for sale (at Home Depot and such) as they all seem to come with sealers as well.

Any suggestions?

	Marble MARBLE: CHARACTERISTICS This standard includes general information on the characteristics and common uses of marble and identifies typical problems associated with the material. INTRODUCTION Marble is an extremely hard, metamorphic stone composed of calcite (CaCO3). It is formed as a result of the recrystallization of limestone under the intense pressure and heat of geologic processes. The effect of this process is the creation of a stone with a very tight crystalline structure and small but definite porosity. Because of its structure, marble can take a very high polish and is a very popular decorative stone for architectural and sculptural uses. The limited porosity of marble, especially polished marble, makes it less vulnerable to the leaching effects of water. Calcium carbonate, however, of which marble is composed, is highly susceptible to attack by acidic agents. Marble is readily dissolved by acids, even very dilute acids, however the actual results of acidic exposure will vary with the nature of the acid. Chlorides, nitrates, sulfates and other chemical compounds react differently with marble and produce various by-products, which have a wide range of solubility and impact on the durability of marble. For this reason, it is always important to determine the exact type of pollutants causing marble deterioration. Marble itself can be of two types, one composed of calcite and the other of dolomite. Dolomitic marble is much more resistant to acid attack than calcite marble. The color of marble ranges from the brilliant white of calcite to black, including blue-gray, red, yellow and green, depending upon the mineral composition. TYPICAL USES Marble has many decorative and structural uses. It is used for outdoor sculpture as well as for sculpture bases; in architecture it is used in exterior walls and veneers, flooring, decorative features, stairways and walkways. The way in which the stone is used may be a factor in limiting or controlling the severity of exposure. The use or function of the marble may also affect the feasibility of applying certain treatments, but type of use is not the primary factor in the major types of deterioration and damage to which marble is susceptible.

[Huligar]

Here is a cleaner that you can try, http://www.nsraweb.com/store/cart.ph...uct_detail&p=5 If you can post an image of the damage stone, we may be able to help you a little more. If this cleaner does not work to your satisfaction, you will need a politice (What Is A Poultice?).

[Timm Sowders]

I would recommend an alkaline stone cleaner and a stiff nylon brush. You will need alkaline to break up the soot. Stonetech professional makes a product called Klenz-All, this is an excellent alkaline cleaner. Once you have got it at clean as it will come then you will need to reclean it with water to nutralize the cleaner. Remember to tape up the area with plastic as that it will be a very messy job. If I were you I would recommend asking here in the forum if there is a restoration professional near you that could help you out. I have done many of these types of job including homes that have had flue fires and they are challenging. Good luck.

	alkaline ALKALINE A water soluble chemical with a pH greater than 7. Some typical alkaline chemicals are ammonia and sodium hydroxide.

[bossofdos64]

Thank you for the advice... I've attached a couple of pictures that show the "damage." Basically, the light beige marble has a smokey grey look to it in the area where the soot rolled up. It was only for a moment but...

I'd be very interested if this is something that is safe enough for me to do or whether I should call in the big guns.

Thanks in advance,

Robert

	Marble MARBLE: CHARACTERISTICS This standard includes general information on the characteristics and common uses of marble and identifies typical problems associated with the material. INTRODUCTION Marble is an extremely hard, metamorphic stone composed of calcite (CaCO3). It is formed as a result of the recrystallization of limestone under the intense pressure and heat of geologic processes. The effect of this process is the creation of a stone with a very tight crystalline structure and small but definite porosity. Because of its structure, marble can take a very high polish and is a very popular decorative stone for architectural and sculptural uses. The limited porosity of marble, especially polished marble, makes it less vulnerable to the leaching effects of water. Calcium carbonate, however, of which marble is composed, is highly susceptible to attack by acidic agents. Marble is readily dissolved by acids, even very dilute acids, however the actual results of acidic exposure will vary with the nature of the acid. Chlorides, nitrates, sulfates and other chemical compounds react differently with marble and produce various by-products, which have a wide range of solubility and impact on the durability of marble. For this reason, it is always important to determine the exact type of pollutants causing marble deterioration. Marble itself can be of two types, one composed of calcite and the other of dolomite. Dolomitic marble is much more resistant to acid attack than calcite marble. The color of marble ranges from the brilliant white of calcite to black, including blue-gray, red, yellow and green, depending upon the mineral composition. TYPICAL USES Marble has many decorative and structural uses. It is used for outdoor sculpture as well as for sculpture bases; in architecture it is used in exterior walls and veneers, flooring, decorative features, stairways and walkways. The way in which the stone is used may be a factor in limiting or controlling the severity of exposure. The use or function of the marble may also affect the feasibility of applying certain treatments, but type of use is not the primary factor in the major types of deterioration and damage to which marble is susceptible.

[Timm Sowders]

If I were you I would start with the daily stone cleaning Huligar recommended above. If that doesn't work then I would recommend calling in someone to help you out with it. An akaline cleaner isn't that hard to work with, but as that it isn't something that you work with, it is something that we work with everyday and know what to expect from it.