BREAK THE MOLD: DAP's Kwik Seal 3.0 kitchen and bath adhesive caulk (top) resists mold and mildew and can be exposed to water three hours after application. (Bottom) Henkel's Polyseamseal Ever Bright silicone sealant uses an "anti-microbial cocktail" and keeps its resistance for five years after application. As homes get tighter, the quality of indoor air becomes a bigger issue. In response to this, caulk and sealant manufacturers are highlighting the mold- and mildew-resistant qualities of their products.

Manufacturers have included mold inhibitors in caulks and sealants for some time, especially products for bath areas. Now some are tweaking formulas or adding anti-microbial treatments to boost resistance capability as consumer interest surges in mold-resistant products.

Wayne Summons, vice president and technical director at Sashco, says most of his company's products include mold inhibitors. However, Mildew Free, which was released in mid-January, combines two active ingredients instead of just one to help prevent mold growth. Summons says the protection lasts at least seven years.

Henkel introduced its Polyseamseal Ever Bright silicone sealant in May. It protects against mold for five years after application, the maker says. Irene Williams, Polyseamseal's brand manager, says the product works by using an "anti-microbial cocktail" to resist mold in three ways: preventing it from adhering, keeping it from spreading, and inhibiting its growth.

DAP included an anti-microbial treatment in its Kwik Seal 3.0 kitchen and bath adhesive caulk, released in August 2007. Shree Naber, DAP's vice president of technology, says the product combines two technologies. The first, an anti-microbial treatment, resists mold and mildew. The second lets the product cure fast enough to be exposed to water in three hours.

Last year, Mapei released its OptiColor grout. The product uses anti-microbial protection to resist stains, mold, and mildew.

Megan Mazur, manager of market development for retail and distribution for Franklin Adhesives, says the company's interior caulks and sealants always have been mold and mildew resistant and pass ASTM standards. This means the resistance lasts for the product's lifetime, she says.

But she says the company has seen an uptick in people seeking mold-resistant products. "It's more of a health concern, creating safer environments to live and work," she says. "It's always been there. Now, it is just more popular."

The EPA stresses that anti-microbial treatments only protect the products themselves. They do not protect users from viruses, germs, food-borne bacteria, or other diseases. Anti-microbial treatments must be registered with the EPA, which requires third-party testing for safety and effectiveness.

Treated products should be thoroughly washed and cleaned. Caulk and adhesive manufacturers, specifically, stress that homeowners should regularly clean bath areas to ensure soap scum does not accumulate.

"Soap films, generally speaking, are not resistant to mildew growth," says Summons from Sashco. "And, being organic materials, they can provide a surface where mildew can grow. The biggest thing a person can do is rinse and wipe down their shower on a regular basis." This will ensure mold and mildew products get their maximum service life, he says.

Mazur emphasizes that to work well, products must be applied correctly to a clean, dry surface. "If you don't get the right bond and there is a gap, something can get under there, and it is going to be a problem," she says.

With the right care, these products can help ensure a bathroom stays mold-free for longer.

–Victoria Markovitz