Grout can often feel like the bane of a homeowner's existence. This cement-based product is integral to nearly all tile installations, particularly those in the bathroom. Keep your grout in good shape to prevent damage to the substrate behind the tile. Replacing the grout should be done not on a fixed schedule, but on an as-needed basis.
Why You Need Grout
Grout serves several purposes for a tile installation. It helps even out inconsistencies in tile sizes and helps prevent damage to tiles in the case of normal house settling or flexing. In the bathroom, grout also helps to prevent water from seeping between the tiles and rotting away the substrate behind it. Unfortunately, water can eventually wear down the grout, causing growth of mold and mildew and cracking of the cement. Normal house settlement and time can also damage the grout in your home.
Regrouting for Damage
Grout can last for a very long time if it isn't being subjected to a lot of movement or water. So while there is no set schedule when grout must be replaced, inspect it periodically to ensure it's still in good shape. Grout that appears to be cracked, missing or peeling should be replaced immediately. The longer that grout is compromised, the more likely it is that water will damage the wall or subfloor behind your tile, causing even bigger problems.
Regrouting for Mold
Grout that is merely discolored due to water stains or absorption of dyes or minerals does not need to be replaced unless you are bothered by its appearance. Grout that appears to be growing mold or mildew, however, may be a sign of a bigger problem. Grout is porous, so when mold begins to grow on its surface, chances are that it is also growing deep inside, which can compromise the integrity of the grout, causing it to fail sooner. Mold can also cause serious health problems in some individuals. If bathroom mold and mildew removers do not appear to stop the mold problem, regrout to eliminate it.
When Not to Regrout
Before you go through the process of chipping out the old grout and mixing up a new batch, make sure that regrouting is the only thing you need to do. Listen for a hollow sound as you tap on your tiles to ensure water hasn't eaten away at the wall behind it. Check for loose tiles or cracked tiles, which could indicate a larger structural issue than just cracked grout. Apply a mold or mildew killing solution to the edges of the tiles themselves after removing mildewed grout to help ensure it hasn't spread, and see that the entire installation has time to dry out thoroughly before applying fresh grout.