Rough granite is a beautiful and durable option for stairs. Granite is a natural stone that has a distinct swirling or spattered pattern of small flecks of a variety of colored minerals. Typically, rough granite resists chipping and cracking caused by wind, rain and freezing temperatures, but it does require a regular care and maintenance program.
Regular Care and Maintenance
Sweep away debris and dirt and rinse your stairs with clean water at least once a week. Buff out water spots or rings with extra fine (0000) steel wool. White powder, called efflorescence, that forms on the granite is caused by water containing mineral salts rising from below the granite’s surface and evaporating. Dust mop or vacuum the powder from the stone and repeat until the dust no longer appears. Rinsing with water will only worsen the problem. If it persists, contact a stone contractor to identify and remove the source of the moisture causing the efflorescence. Prevent water problems by mopping the stairs to remove rainwater as soon as possible after it rains. Shovel the steps frequently during the winter months to remove snow and ice, which are also fall-hazards on stairs.
Pool and Patio Areas
If your granite stairs are near a pool, patio, or hot tub area, algae and moss may be an issue. Regularly flush the steps with clean water. If algae and moss growth occur, clean with a solution of 1/2 cup ammonia or hydrogen peroxide in a gallon of water. Never mix ammonia with bleach or bleach-based products. These combine to create a toxic gas. Rinse the steps thoroughly with water after cleaning.
Because it is a porous surface, rough granite is subject to a variety of staining agents. Oil-based stains, such as grease or tar, darken rough granite and must be chemically dissolved using ammonia, mineral spirits or acetone and then rinsed thoroughly with clean water. Organic stains, such as bird droppings, leaves or food typically leave a pinkish brown stain, but are bleached out by the sun and rain over time. Remove fresh paint spills with paint thinner. Dry paint may have to be scraped from your stairs with a razor blade. A problematic stain for most natural stone is rust, but there are poultices available from stone companies that contain chemicals which break down and remove metal stains. Never use cleaners that contain acids, such as bathroom cleaners, grout cleaners or tub and tile cleaning products, or abrasive cleansers, which may etch the granite.
About Sealing Rough Granite
Rough granite is a hard and durable stair material, but it is also porous so it can absorb water and other liquids. If you expect the stairs to be subject to staining agents, such as metal, leaf debris, or moisture, sealing may be beneficial. However, avoid topical sealers, which are film-forming coatings designed to protect the surface of natural stone. These may affect the surface color of the granite and aren’t recommended for exterior stairs because they trap moisture in the top layer of the stone, which can lead to deterioration of the granite as it goes through regular freeze and thaw cycles. A better option for sealing exterior granite steps is using impregnators, which are water- or solvent-based solutions that penetrate the stone and act as repellents. Impregnating sealers repel both oil and water, but they don’t stop moisture already within the granite from escaping, so freeze and thaw cycles won’t damage the stone.