Loose tiles are a bad gift that keeps on giving for unsuspecting homeowners. Tiles lifting from the floor indicate a seriously compromised tile installation, and they can also be a red flag drawing attention to what's taking place beneath the surface. Removal of the tile and inspection of the floor underneath is always necessary.

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A variety of factors can cause tile to lift up.

Moisture

Moisture causes a variety of unwanted effects beneath tile, culminating in a compromised substrate-tile bond — the substrate is the tile installation surface. Moisture may be coming up through your home's concrete slab, causing the tiles to lift up, or loose tile may indicate an unseen plumbing leak inside a wall. Remove all individual pieces of loose tile. Inspect the substrate, whether it's concrete, cement board or plywood. Check for dampness and moisture-related mold. Consult a professional if moisture is seeping up through the concrete slab. Remove mold with a bleach solution before reinstalling the tile. Contact a mold specialist in extreme scenarios.

Substrate Movement

Another common cause of tiles lifting up is substrate movement. For example, improperly installed cement board expands over time, causing tile to work loose on both flooring and wall applications. A cracked concrete slab — or one that is in the process of expanding — may also cause tile to lift up. Remove the loose tiles and inspect the substrate. In some cases, simple repair is all that's required. In extreme scenarios, the substrate will have to be removed.

Compromised Installation or Inadequate Bond

Inadequately installed tile becomes loose over time. For example, a tile contractor may decide to save a few dollars by using a low-grade, unmodified thin-set with porcelain tile. Unmodified thin-set does not adhere to porcelain tile, and the pieces will eventually come loose. Check for the amount of thin-set left on the substrate after removal — if the tile comes up clean, leaving most of the thin-set on the substrate, chances are a low-grade thin-set is the culprit. Additionally, an improper substrate — such as tile installed on drywall in a shower — causes tile to fail. Tile removal and demolition may be required.

Loose Tile Removal Tips

Be patient when removing loose tile. Use a small crowbar and carpenter's hammer for removal. Don't apply too much pressure initially. Remove the adjoining grout with a carbide-tipped grout saw before you attempt to remove individual tiles. Pry up the perimeter of the first piece until you hear a slight popping sound, indicating the piece is no longer bonded to the substrate. To reuse the tile, grind thin-set off the back with a 4-inch grinder. Clean the substrate and perform any necessary repairs before reinstallation.