Why tile flooring cracks and how to prevent it

Speedwell Design Center
September 14 2017
Tile flooring is easy to work with, durable and functional. When properly installed it can offer years of problem free service. Sometimes however, tile flooring cracks. Often, the problem lies not with the material, but with what is hidden below the surface. Let's explore some common causes of tile flooring cracks and how proper installation can prevent it.

Four Common Causes

When properly installed tile flooring is a durable surface that can stand up to heavy use with few signs of wear. However, in certain circumstances tile cracks. Often the homeowner immediately believes that the cause is defective materials. While this is sometimes the case, today most tile sold is crafted to be in compliance with ANSI and ASTM testing standards. There are four common causes for tile flooring cracks, and all of them are related to the installation process.
  • Improper Subfloor Preparation– Your subfloor forms the foundation for your tile. It must not only be flat and stable but before tiling, it must also be clean. Along with vacuuming up particles, your subfloor should be mopped with a solvent such as mineral spirits to remove any oils, grease or wax that could cause the mortar to improperly set, which can cause cracking.
  • Improperly Applied Mortar – Mortar should be spread evenly and given time to properly cure. If the mortar is only adhering to a portion of the tile, or if it isn't completely hardened, your tile could shift and crack.
  • Improper Expansion Joints – Expansion joints are the spaces left between the tile during installation which are then grouted. Expansion joints absorb pressure from shifting tiles. If they are too thin, the tiles will not have room to expand and contract and this can cause cracking.
  • Tile Flooring Installed Over Concrete is Most Susceptible To Cracking – This is because concrete itself is susceptible to cracking. Hairline cracks will not generally cause problems, but if a crack forms in the concrete subfloor that is wider than 1/8” it will eventually shift to the tile. This is known as reflective cracking.

How To Prevent Cracking

For wooden subfloors, the surfaces must be properly prepared prior to installation. Make sure your subfloor is level and stable. Thoroughly vacuum and mop the surface using mineral spirits to remove any oils, wax or adhesives before applying mortar. Make sure the mortar is evenly applied and allow for proper curing before laying tile. When laying your tile, use the appropriate spacers to ensure adequate expansion joints. For concrete subfloor, use an uncoupling and crack isolation membrane with rounded square-shaped reliefs. This material solves two of the most common isolation issues that cause cracking; it ensures a stable flat surface, and isolates the tile from the concrete subfloor preventing reflective cracking. To prevent tile floor cracks, proper preparation of the surface to be tiled is necessary. Taking a few extra minutes to ensure that your subfloor is properly prepared to ensure the tile will result in years of maintenance and problem-free use!

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