The most common form of maintenance for Louis W. Mian natural stone is the removal of stains. Please refer to our General Care page for a complete listing of the various foods, beverages, and chemicals that can damage natural stone.
The purpose of a sealer is to treat the natural stone so it repels dirt and water and increases stain resistance. It penetrates the stone, thereby reducing absorption, keeping dirt and staining agents on the stone surface.
Some sealers my darken certain stones. Sealers are somewhat ineffective in protecting the surface of the stone against oil, grease, and similar contaminants. Most sealers are not single application products; they must be periodically applied in order to provide protection.
Some types of sealers tend to create a less durable top layer, which will invariably increase your maintenance of the stone. Also, sealers are not recommended in exterior applications, because they can trap moisture within the top layer of stone, which may lead to surface cracks during freeze-thaw cycles.
Identifying Stains and Stain Removal:
Natural stone is a porous material susceptible to staining. Granite is much less porous than the other natural stones, and is therefore much less likely to stain. The level of porosity in the stone dictates the degree of ease or difficulty in removing the stain. In order to remove a stain, the staining process must be reversed. Originally the stone absorbed the stain; now the stain must be broken down chemically and reabsorbed into a different material. This different material is what we call a Poultice, which is a white powder and the appropriate chemical required to reactivate the stain. This is why it is important to identify the stain, thereby choosing the correct chemical. If, after thorough investigation you have no idea what type of stain you have, then test patches will be necessary. This means applying several different chemical poultices in order to determine which one will remove the stain.
Various Types of Stains:
- Oil Based: grass, tar (asphaltic based products), cooking oils, butter, mayonnaise, etc.
- Metal and Rust: iron, copper, bronze, etc.
- Biological: algae, mildew, etc.
- Ink: magic marker, ink, etc.
Poultice Application:
1) Wet the stained area with distilled water. Pre-wetting fills the pores of the stone with water by isolating the stain and accelerating the chemical reactivation.
2) Prepare the poultice. Premix the powder and the chemical of choice into a thick paste (about the consistency of peanut butter).
2a) If paper poultice is to be used, soak the paper in the chemical, lift the paper out of the chemical until it stops dripping and apply it to the stained area.
3) Apply the poultice to the stain, being careful not to spill any on the non-stained areas. Apply minimum 1/4 inch thick, overlapping the stained area by about 1 inch.
4) Cover the poultice with plastic (food wrap works fine). Tape the plastic down to seal the edges.
5) Allow the poultice to dry thoroughly. This is a very important step. The drying of the poultice is what pulls the stain from the stone into the poultice material. If the poultice is not allowed to dry, the stain may not be removed. Drying usually takes from 24 to 48 hours.
6) Remove the poultice from the stain. Rinse with distilled water and buff dry with a soft cloth. If the stain is not removed, apply the poultice again. It may take up to five applications for difficult stains.
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