Do You Silicone Caulk the Inside Corner of Your Tile Backsplash?

Expansion Joints

• Every change of plane in a tile installation requires the use of an expansion joint. This includes the area where two walls meet in an inside corner. Expansion joints absorb movement that may occur due to thermal changes in the room, the house settling or a wall shifting. Without an expansion joint, the tiles on your backsplash may tent, move or crack over time. Because grout cannot flex and move, it is never used in an expansion joint. Instead, fill this gap with a more flexible material, such as latex or silicone caulk.

When to Use Latex

• Make the selection of the material you plan on using based upon the area, the tile and the home. For the vast majority of tile backsplashes, silicone caulk is considered overkill and is not used. Silicone is the most waterproof and durable caulk material available, making it ideal for floors, wet areas and outdoor applications. Most backsplashes, however, do not get the kind of use that would warrant silicone. Additionally, silicone is clear and cannot be painted, leaving an obvious color change in the corners of the backsplash. Latex caulk, however, is available in a range of colors to match the grout used in the installation. For ceramic, porcelain and stone installations, run a bead of latex caulk in the corners and where the tile meets the counter.

Kitchens With Windows

• Any expansion joint that sees a lot of movement over time requires the use of silicone caulk. While latex is used in the vast majority of backsplash installations, it can fail over time if the joint is flexed continuously. One of the biggest causes of repeated movement along an interior joint not exposed to water is thermal changes. Kitchens that have a lot of windows may experience greater and more frequent thermal changes than a kitchen without windows. When the kitchen heats and cools due to excessive sunlight, the studs in the walls may swell and contract, flexing the joint repeatedly. In any kitchen where there is a lot of direct sunlight, use silicone caulk in the corners.

Glass Tile

• Brittle and fragile, with a low tensile strength, glass tile requires special installation. While expansion joints are important to any tile installation, they are crucial to a glass tile installation because the tile cannot flex in any way without cracking or splintering. While some glass tile manufacturers recommend a latex-additive caulk for the expansion joints of the installation, others require silicone for its greater ability to flex and absorb any movement before it can be transferred to the tiles. Always check with the manufacturer when installing glass tiles to get their recommendation on what material to use in inside corners.