Sealing grout is an important detail when installing tile that is often overlooked. Many professionals and DIY’ers overlook sealing grout lines after a tiling job, but this step can ensure the beauty of your tils as well as maintain the integrity of your tiling job.

Many people believe that grout lines are simply a decorative margin that helps define the borders of your tile, but they are also part of the structural assembly of the tile floor. The grout secures the tile matrix together with a hard and inflexible filler between the tile gaps. Although grout is extremely strong and resistant to expansion or abrasion, it does have the limitation of porosity. This is a problem that will get worse over the lifetime of the grout, particularly in areas with repeated exposure to moisture such as a bathroom.

When unsealed grout is exposed to moisture, the grout lines absorb water and become pitted over time. This problem usually happens first but is not highly visible to the untrained eye. Grout is also very susceptible to bacteria growth within the grout, which causes staining and discoloration. This is particularly apparent in a shower, when water enters and stays within the grout constantly, never drying out completely. Water from a shower or bath is particularly harmful since the water tends to be at a warm temperature which when combined with the low pH of soaps and shampoos causes chemical changes in the structure of the grout. In extreme situations, particularly inside a shower, this grout can deteriorate to the point that the bacteria growth spreads into the entire grout matrix, allowing bacteria and moisture to grow behind the tile and penetrating all through the drywall.

Floor tile grout gently suffers less abuse than shower tile, but it is also easily stained and can become difficult to clean due to frequent water exposure as well as a build-up of dirt and grime. When cleaning a tile floor, most people are simply wiping water across the tiles, which allows the dirty water to stain the grout lines between the tiles. Interestingly, the more you clean your floors the more stained the grout lines become since you are more consistently spreading dirty and discolored water into your grout lines.

Tile floors are beautiful and an investment in your home, so keep them in good condition by simple grout sealing. The cost varies depending on the product, but a flooring specialist can recommend an option that will work with your budget and needs. Grout sealer will need a few extra days to dry and will need to be reapplied as often as once per year. You will know it is time to reseal the grout when water exposure begins to slightly darken the grout lines, but keeping up with reapplication can preserve your tile floors for years to come.

Another newer option is to use a tile grout which is made with an acrylic compound within the grout. Usually the traditional bonding agent used is Portland cement, but the addition of this plastic-like compound helps to solve some of the problem with traditional tile grout. Look for grouts which are advertised as being “pre-sealed” or an “epoxy grout” as an indicator that they contain acrylic components. As a recent product, it can be hard to predict the longevity of this type of grout but it is highly water resistant, dries hard, and resistant to staining and discoloration.