MIA Statement of Position On Sealing Natural Stone Countertops

Most granite countertops do not need to be sealed. Before 1995 there were very few quality penetrating sealers on the market and there were very few cases of staining. Both prior to and after the availability of penetrating sealers, no cases of food poisoning, radon, or food preparation issues associated with treated or untreated granites have been reported. If a homeowner cleans their countertops after each meal, they will rarely, if ever, have staining or cleanability issues with granite. This being said, many granite countertops receive additional benefit from being sealed. That benefit is the further reduction of moisture migration into an already moisture resistant surface.

Should natural stone counters be sealed? In many cases it makes sense to seal marble and granite countertops with a quality sealer. The product should have a life expectancy of ten to fifteen years and be of an oliophobic (resistant to water and oil based stains) nature. Once properly sealed, the stone will be more resistant against everyday dirt and spills.

In today's natural stone industry, many species of granite receive a resin treatment at the factory where the blocks of granite are cut into slabs and then polished. The treatment is used to fill micro-fissures, indentations and other minor characteristics that are found in many natural stones. The reason for the resin treatment is to address what most consumers consider as imperfections, but in reality are "birth marks". The consuming public gravitates to perfection, defined as no "birth marks," and so the marble and granite industry tries to fulfill the desire. Both resined as well as unresined slabs will outlast most of our lifetimes. Granite should, and in most cases will, be the last countertop surface a person will buy, providing a strong return on investment. The bottom line: Sealing resin treated countertops may increase the resistance of the already resistant nature of stone (adopted 11/8/06).

Like all other materials, granite and marble require regular maintenance with use that if done on a regular basis can prevent any chance problems and extend the life span of your natural stone.

According to Marble Institute of America, stone maintenance includes:

General Care

Care and Precautions

Use coasters under all glasses, especially those containing alcohol or citrus juices. Some foods and drinks contain acids that will etch or dull the surface of many stones. Do not place hot items directly on the stone surface. Use trivets or mats under objects that can scratch the surface.

Cleaning Procedures and Recommendations

Other Surfaces

Clean stone surfaces with a few drops of neutral cleaner, stone soap (available at hardware stores or from your stone dealer) or a mild liquid dishwashing detergent and warm water. Use a clean rag mop on floors and a soft cloth for other surfaces for best results. Too much cleaner or soap may leave a film and cause streaks. Do not use products that contain lemon, vinegar or other acids on marble or limestone. Rinse the surface thoroughly after washing with the soap solution and dry with a soft cloth. Change the rinse water frequently. Do not use scouring powders or creams; these products contain abrasives that may scratch the surface.

Bath and Other Wet Areas

Use a squeegee after each use. To remove soap scum, use a non-acidic soap scum remover or a solution of ammonia and water (about 1/2 cup ammonia to a gallon of water). Do not over-use ammonia solution. It may dull the surface of the stone.

Vanity Top Surfaces

Vanity tops may need to have a penetrating sealer applied. Check with your installer for recommendations. A good quality marble wax or non-yellowing automobile paste wax can be applied to minimize water spotting.

Food Preparation Areas

In food preparation areas, the stone may need to have a penetrating sealer applied. Check with your installer for recommendations. If a sealer is applied, be sure that it is non-toxic and safe for use on food preparation surfaces. If there are questions, check with the sealer manufacturer.

Outdoor Pool & Patio Areas

In outdoor pool, patio or hot tub areas, flush with clear water and use a mild bleach solution to remove algae or moss.

Stains

Spills and Stains

Blot the spill with a paper towel immediately. Don't wipe the area, it will spread the spill. Flush the area with plain water and mild soap and rinse several times. Dry the area thoroughly with a soft cloth. Repeat as necessary. If the stain remains, refer to the section in this brochure on stain removal.

Stain Removal

Identifying the type of stain on the stone surface is the key to removing it. If you don't know what caused the stain, play detective. Where is the stain located? Is it near a plant, a food service area, an area where cosmetics are used? What color is it? What is the shape or pattern? What goes on in the area around the stain? Surface stains can often be removed by cleaning with an appropriate cleaning product or household chemical. Deep-seated or stubborn stains may require using a poultice or calling in a professional. The following sections describe the types of stains that you may have to deal with and appropriate household chemicals to use and how to prepare and apply a poultice to remove the stain.

Types of Stains and First Step Cleaning Actions

OIL-BASED

(grease, tar, cooking oil, milk, cosmetics)

An oil-based stain will darken the stone and normally must be chemically dissolved so the source of the stain can be flushed or rinsed away. Clean gently with a soft, liquid cleanser with bleach OR household detergent OR ammonia OR mineral spirits OR acetone.

ORGANIC

(coffee, tea, fruit, tobacco, paper, food, urine, leaves, bark, bird droppings)

May cause a pinkish-brown stain and may disappear after the source of the stain has been removed. Outdoors, with the sources removed, normal sun and rain action will generally bleach out the stains. Indoors, clean with12% hydrogen peroxide (hair bleaching strength) and a few drops of ammonia.

METAL

(iron, rust, copper, bronze)

Iron or rust stains are orange to brown in color and follow the shape of the staining object such as nails, bolts, screws, cans, flower pots, metal furniture. Copper and bronze stains appear as green or muddy-brown and result from the action of moisture on nearby or embedded bronze, copper or brass items. Metal stains must be removed with a poultice.(See section on Making & Using a Poultice) Deep-seated, rusty stains are extremely difficult to remove and the stone may be permanently stained.

BIOLOGICAL

(algae, mildew, lichens, moss, fungi)

Clean with diluted (1/2 cup in a gallon of water) ammonia OR bleach OR hydrogen peroxide. DO NOT MIX BLEACH ANDAMMONIA! THIS COMBINATION CREATES A TOXIC AND LETHAL GAS!

INK

(magic marker, pen, ink)

Clean with bleach or hydrogen peroxide (light colored stone only!) or lacquer thinner or acetone (dark stones only!)

PAINT

Small amounts can be removed with lacquer thinner or scraped off carefully with a razorblade. Heavy paint coverage should be removed only with a commercial "heavy liquid" paint stripper available from hardware stores and paint centers. These strippers normally contain caustic soda or lye. Do not use acids or flame tools to strip paint from stone. Paint strippers can etch the surface of the stone; re-polishing may be necessary. Follow the manufacturer's directions for use of these products, taking care to flush the area thoroughly with clean water. Protect yourself with rubber gloves and eye protection, and work in a well-ventilated area. Use only wood or plastic scrapers for removing the sludge and curdled paint. Normally, latex and acrylic paints will not cause staining. Oil-based paints, linseed oil, putty, caulks and sealants may cause oily stains. Refer to the section on oil-based stains.

WATER SPOTS AND RINGS

(surface accumulation of hard water)

Buff with dry 0000 steel wool.

FIRE AND SMOKE DAMAGE

Older stones and smoke or fire stained fireplaces may require a thorough cleaning to restore their original appearance. Commercially available "smoke removers" may save time and effort.

ETCH MARKS

Etch marks are caused by acids left on the surface of the stone. Some materials will etch the finish but not leave a stain. Others will both etch and stain. Once the stain has been removed, wet the surface with clear water and sprinkle on marble polishing powder, available from a hardware or lapidary store, or your local stone dealer. Rub the powder onto the stone with a damp cloth or by using a buffing pad with a low-speed power drill. Continue buffing until the etch mark disappears and the marble surface shines. Contact your stone dealer or call a professional stone restorer for refinishing or re-polishing etched areas that you cannot remove.

EFFLORESCENCE

Efflorescence is a white powder that may appear on the surface of the stone. It is caused by water carrying mineral salts from below the surface of the stone rising through the stone and evaporating. When the water evaporates, it leaves the powdery substance. If the installation is new, dust mop or vacuum the powder. You may have to do this several times as the stone dries out. Do not use water to remove the powder; it will only temporarily disappear. If the problem persists, contact your installer to help identify and remove the cause of the moisture.

SCRATCHES AND NICKS

Slight surface scratches may be buffed with dry 0000 steel wool. Deeper scratches and nicks in the surface of the stone should be repaired and re-polished by a professional.

Poultices

Making and Using a Poultice

A poultice is a liquid cleaner or chemical mixed with a white absorbent material to form a paste about the consistency of peanut butter. The poultice is spread over the stained area to a thickness of about 1/4 to 1/2 inch with a wood or plastic spatula, covered with plastic and left to work for 24 to 48 hours. The liquid cleaner or chemical will draw out the stain into the absorbent material. Poultice procedures may have to be repeated to thoroughly remove a stain, but some stains may never be completely removed.

Poultice Materials

Poultice materials include kaolin, fuller's earth, whiting, diatomaceous earth, powdered chalk, white molding plaster or talc. Approximately one pound of prepared poultice material will cover one square foot. Do not use whiting or iron-type clays such as fuller's earth with acid chemicals. The reaction will cancel the effect of the poultice. A poultice can also be prepared using white cotton balls, whitepaper towels or gauze pads.

Applying the Poultice

Prepare the poultice. If using powder, mix the cleaning agent or chemical to a thick paste the consistency of peanut butter. If using paper, soak in the chemical and let drain. Don't let the liquid drip.

Wet the stained area with distilled water.

Apply the poultice to the stained area about1/4 to 1/2 inch thick and extend the poultice beyond the stained area by about one inch. Use a wood or plastic scraper to spread the poultice evenly.

Cover the poultice with plastic and tape the edges to seal it.

Allow the poultice to dry thoroughly, usually about 24 to 48 hours. The drying process is what pulls the stain out of the stone and into the poultice material. After about 24 hours, remove the plastic and allow the poultice to dry.

Remove the poultice from the stain. Rinse with distilled water and buff dry with a soft cloth. Use the wood or plastic scraper if necessary.

Repeat the poultice application if the stain is not removed. It may take up to five applications for difficult stains.

If the surface is etched by the chemical, apply polishing powder and buff with burlap or felt buffing pad to restore the surface.

Cleaning Agents or Chemicals

OIL-BASED STAINS

Poultice with baking soda and water OR one of the powdered poultice materials and mineral spirits.

ORGANIC STAINS

Poultice with one of the powdered poultice materials and 12% hydrogen peroxide solution (hair bleaching strength) OR use acetone instead of the hydrogen peroxide.

IRON STAINS

Poultice with diatomaceous earth and a commercially available rust remover. Rust stains are particularly difficult to remove. You may need to call a professional.

COPPER STAINS

Poultice with one of the powdered poultice materials and ammonia. These stains are difficult to remove. You may need to call a professional.

BIOLOGICAL STAINS

Poultice with dilute ammonia OR bleach OR hydrogen peroxide. DO NOT MIX AMMO-NIA AND BLEACH! THIS COMBINATIONCREATES A TOXIC AND LETHAL GAS!

Dos and Don'ts

DO Dust mop floors frequently

DO Clean surfaces with mild detergent or stone soap

DO Thoroughly rinse and dry the surface after washing

DO Blot up spills immediately

DO Protect floor surfaces with non-slip mats or area rugs and countertop surfaces with coasters, trivets or placemats

DON'T Use vinegar, lemon juice or other cleaners containing acids on marble, limestone, travertine or onyx surfaces

DON'T Use cleaners that contain acid such as bathroom cleaners, grout cleaners or tub & tile cleaners

DON'T Use abrasive cleaners such as dry cleansers or soft cleansers

DON'T Mix bleach and ammonia; this combination creates a toxic and lethal gas

DON'T Ever mix chemicals together unless directions specifically instruct you to do so

Call your professional stone supplier, installer or a restoration specialist for problems that appear too difficult to treat.

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