Pictured above is the One & Only collection of vilbostone porcelain stoneware from Villeroy & Boch. Photo courtesy of Villeroy & Boch.


Q: After several bad experiences, I am concerned about the growth of mold and moisture seepage problems occurring under my tile installations. Should I be and what can I do to address this during the pre-tile phase?

A:It’s ironic when you think about it, but the fact is that kitchens and bathrooms, the places where your clients most love the stylish look of tile, can be the worst environment for tiling. High moisture, heat, water exposure, condensation and confined spaces all spell trouble for the tile job essentials of tile backer, tile and grout finish.

Mold and moisture are, of course, the big concerns. Mold, the most common form of fungus, grows easily where moisture is high. And, the dirt and grime which easily accumulate in places where washing occurs, like sinks and tubs, are a food source for mold. Moisture is everywhere, particularly in today’s kitchens and bathrooms which have more water features than ever including multiple sinks, waterfall, steam and multi-head showers. All these water features also present more potential problems from behind the walls water leakage.

When it comes to keeping moisture and mold away from tile installations, both behind the wall and in front, the key is prevention in the installation process, than sealing, and sealant maintenance, through the long haul.

What Lies Beneath
The first step to a moisture and mold preventing tile installation is the part your clients don’t see, but should care about – the tile backer selection. The backer to which you’ll adhere tile to should serve not only as the base for your tiles, but to deter mold and moisture. Ideally, your selection of tile backer will meet local, state and national building codes and have certifications that prove its efficacy in important areas like resisting mold growth and from organizations that test products for their sustainable attributes, like GreenGuard Environmental Institute.

Contractors should choose a tile backer that prevents moisture from invading the wall cavity. New technology has widened the options of tile backer offerings to include products that not only withstand water seepage, but can prevent mold by offering microbial resistance.

In 2006, the International Code Council (ICC) withdrew its approval of greenboard as a tile backer in wet areas due to poor performance in preventing water seepage. Fiberglass mat gypsum tile backer is an ideal alternative to cement-based backer boards. With a water-resistant fiberglass mat covering both sides of a gypsum core and a moisture barrier on the face of the panel, these panels form a barrier that helps prevent water vapor and moisture from penetrating the wall cavity. Because they do not have paper facings, fiberglass mat gypsum tile backers also eliminate a potential food source for mold growth. Also, these panels do not require the added step of using a membrane in wet areas, as stipulated in the“Tile Council of North America Handbook for Ceramic Tile Installations,”because the moisture-resistant acrylic coating is built into the face of the product.

Grout Performance, Maximized
Though it has a big role in tile installation, the truth is grout is a porous material that not only absorbs water, but mold-attracting dirt.

There are new grout options available – some with polymers that resist moisture and anti-microbial features. And, new grout sealers are effective in blocking moisture. To prevent water from penetrating porous grout, it is good maintenance practice to reseal the grout every six months to one year.

Seal, Seal Away
After the installation is complete and caulk is applied, taking extra steps to note where and how the room is set up and where water seepage trouble spots and moisture emits from can be a boon for the longevity of your tile installation.

As the final step in a mold and moisture preventing strategy, be sure to seal all gaps throughout the kitchen or bath with a flexible sealant to create a tighter, moisture and mold free and comfortable environment for your clients.


Editor’s Note:The views expressed within this article are those of the individual author, and are not to be attributed toTILE Magazine/BNP Media.