Singing the Praises of Natural Stone in the Shower

By Stephanie Vozza

When it comes to beauty, few building materials can compete with natural stone. One-of-a-kind markings, dramatic colors, and rich finishes make it a popular choice, especially in bathrooms where it can transform a utilitarian space into a spa-like retreat. Long considered a great choice for countertops, more homeowners are now also having natural stone installed in the shower.

“Stone can be a good choice for the shower, but it does require special care and maintenance,” says David Bonasera, owner of ESP, a San Jose, California-based distributor of environmentally safe cleaning and sealing products for natural stone. “The most important thing you can do is to be a good steward to the stone.”

 

First Know Your Material

Your success will depend on the material you choose, says Gregory Mowat, founder of Forensic Tile Consultants in San Diego, California, who investigates stone failure and assemblies. While marble is a beautiful and popular choice for bathrooms, homeowners should be aware that it should be sealed prior to use in the shower. “Marble soundness is classified as A, B, C, or D,” Mowat says. “Soundness classifications A and B have few veins or inclusions, and marbles classified as D and C have more. When moisture gets into the vein composition it can cause damage.”

Water can also cause discoloration in white marble. According to Bonasera, this is because some white marbles contain naturally occurring iron-bearing minerals. “With enough water it will start to rust. It’s vital that marble is properly sealed and maintained.”

A useful generalization is that the lighter the stone, the more porous it is. “Darker stones have a tighter molecular structure and are less likely to stain” Bonasera says. There are many exceptions to this concept, and a knowledgeable stone supplier and fabricator can help guide you to a suitable material.

Granite is a good choice for bathrooms, says Jacqueline Tabbah, vice president of International Stoneworks, Inc., a stone restoration company in Houston, Texas. “Most granites are easier to maintain because they don’t react to the three As: acid, ammonia and alcohol,” she says. “Acid reacts to marble and travertine, and etches the surface, removing the polished finish.”

 

Pearl Grey marble. Photo courtesy of Polycor.

Pearl Grey marble. Photo courtesy of Polycor.

Know How to Care For It

No matter what material you use, there will always be maintenance, says Tabbah. “Customers may decide not to use natural stone [because they are concerned about upkeep], but porcelain tile can become discolored and grout lines can darken,” she says. “There is always upkeep, it will just be different.”

When cleaning natural stone, it is best to keep things simple. Soapy cleaners can add buildup and attract dirt, while vinegar and harsh cleaners can damage the stone. To avoid these issues, always use a neutral cleaner with a pH level of around seven.

A few quick preventative measures can keep stone surfaces looking fresh. To help avoid water marks on the stone surface, use a squeegee on the walls after showering. Bonasera also recommends leaving the door open. “Clients who keep their door open hardly have any mildew. Moisture needs to escape, and it will take the path of least resistance.”

Bonasera also recommends using glycerin over traditional bar soap.  “It’s transparent and doesn’t have a lot of fat, lye and animal byproducts that are in regular soap,” he says. “It will cut soap scum. Soap scum is a food source for mold.”

 

Montauk Black slate. Photo courtesy of M S International.

Montauk Black slate. Photo courtesy of M S International.

Know Its Maintenance

Stone should be sealed when used in bathrooms that receive daily use. “We recommend a penetrating sealer once a year,” says Tabbah. “It helps repel water so it beads up instead of soaking in and turning the stone darker.”

While sealing stone is something the average homeowner can do, it is important to follow the instructions. For best results, hire a stone professional or restoration specialist.

“Get a guarantee in writing from a reputable contractor, someone who will be accountable,” says Bonasera.

Even the tidiest homeowner should consider hiring a professional to come out every two to five years to have the stone rehoned or repolished, says Tabbah: “We get a lot of calls to refinish the stone because it loses its luster over time due to water exposure or calcium deposits,” she says.

Most homeowners will agree that the beauty of natural stone is worth the upkeep. “As long as the customer is aware of how to care for and maintain it, it’s not as difficult as they might expect,” says Tabbah. “Do your homework and be knowledgeable about the material. It will look beautiful for years to come.”