By Mike McClintock Special to Tribune Newspapers
July 7, 2012
Tile floors and counters would be nearly indestructible if it weren't for all the seams filled with grout. Applied on a solid surface, ceramic tile won't fade, stain or crumble, and its surface is easy to clean. The grout is another story.
Specialized mixes like acid-cure and epoxy grout used mainly for commercial applications are almost as impervious as tile. But they're difficult to install and not in the arsenal of many contractors, much less DIYers. Grout mixes that are commonly used in homes are not as solid and need maintenance. And in damp areas like kitchens, baths and laundry rooms, all too often it's regular maintenance.
As grout absorbs moisture it quickly sprouts mold and mildew, the main cleaning headache. But appearance is only part of the problem. Water can also gradually erode porous grout. Then, instead of sitting on the surface and causing cleaning problems, moisture seeps through joints and causes structural problems. If a plywood counter is covered with cement board before tile, leaks may take months to cause any damage. If tiles are set in adhesive over plywood, leaks will cause wood rot, break the adhesive bond, delaminate the layers of wood and disrupt the tiles.
Cleaning Many proprietary cleaners will work on the main problems: soap residue and mold. For soap residue, use an all-purpose, nonabrasive cleaner, scrub with a sponge and rinse. If a haze remains, try a specialized product such as Tilex Soap Scum Remover, or apply a mound of baking soda and liquid detergent patted over the area and left for several hours to draw out the stain. For mold, most effective cleaners are based on sodium hypochlorite (bleach). The home brew version starts at one part per 10 parts water. For that and stronger solutions ventilate the area and wear rubber gloves. It's also wise to test your cleaner on a small area, particularly on dark grout. If you find bleach too caustic, try alternatives, including borax, vinegar, hydrogen peroxide and ammonia. For stubborn stains use a poultice of household bleach and a scouring powder (don't combine ammonia and bleach) covered with plastic and left on the stain overnight.
Repairing The first sign of deterioration is hairline cracking. Liquid silicone can seal those potential leaks and prevent further damage. Once grout is cracked and loose, the seam is porous and has to be replaced. Start by prying up or digging out any loose material — with a small grout saw if necessary — and letting any damp areas dry. Grout-digging power tools work faster but can be difficult to keep in the joint and off of surrounding tiles. But if leaks have broken the adhesive bond and tiles are loose, they have to be reset as well. Start by mixing a small batch of grout and letting it dry to check for a color match. Where a close match is important you may have to mix several batches, adjusting the amount of powdered colorant. The easiest option is a prepared grout (typically labeled ready-mix). UGL, Savogran and others make quick-curing, mildew-resistant acrylic-latex grouts. Force the grout into seams with diagonal strokes of a sponge float or squeegee. When dry, clear the grout haze from nearby tiles with a sponge and clean water.
Sealing Because scrubbing grout is time-consuming, consider an extra job after the new grout sets: sealing the seams with liquid silicone. It's tedious, more so for two applications and better protection, because you have to coat only the grout. Silicone on tile would make the surface slippery. You can use an artist's brush or small, roll-on dispenser. Companies including DuPont, Aqua Mix, Homax offer sealers with an applicator attached.