Grouting to Prevent Water Seepage Behind Wall Tiles

Effects of Water Seepage

• When water seeps into the cracks between tiles, it gets into the mortar that secures the tiles to the walls. Over time, the water breaks the adhesive down and causes it to fail, which results in the tiles falling from the wall. A tile job does not require direct contact with water, such as in a shower, in order for seepage to occur. Constant humidity may also cause seepage that can damage adhesive.

Grouting

• Grout is applied to tiles by spreading the mixture over the tiled surface once the tile adhesive has fully dried, which generally takes between 24 and 48 hours. A grout float or trowel may be used to spread the grout and any grout on the tile surfaces should be wiped up immediately. Grout should be used only for those spaces between the tiles, not for spaces at the edges of the tile job where the grout meets the floor or ceiling or fixtures, like a bathtub.

Caulk

• The spaces that you do not fill with grout, like the gap where the wall tiles meet the floor or ceiling and the gaps at fixtures, should be filled with caulk instead of grout. Unlike grout, caulk comes in a tube with an applicator tip and is applied to the tiles directly from the container. When caulking the edges and fixtures in a tile job, the caulk should be applied in one long strip whenever possible to prevent gaps in the caulk where water may get in.

Waterproofing

• Once wall tiles are grouted and caulked, the homeowner should waterproof the fillers if the tiles are in a location with constant moisture by applying a transparent sealer to the grout and caulk with a small paintbrush. Applications should avoid getting the sealer on the surfaces of tiles if they already have a coating, such as coated ceramic or porcelain tiles. If the tiles are not pre-coated, such as stone or slate, homeowners need to seal the tiles and the fillers between them.