Under the Surface: Four Conditions Tile Cracks May Indicate

Cracked tiles may seem like an aesthetic issue, as tiles are usually chosen for their visual appeal and placed over the more structurally important components. However, they’re often symptoms of more extensive issues, and ignoring them can be a serious mistake.

Tiles have little to no give once they’re installed, so their environment plays a huge part in keeping them in place and intact. Changes to that environment, incorrect installation, or unexpected impact or weight, can all lead to cracks in the tiles. An expert familiar with tiles and other flooring components can determine the underlying cause of the cracks.

Cracked Floor Tiles

Cracked floor tiles often point to issues that are more than just surface deep.

Impact Damage

This is the most localized cracking and often the easiest cause of loss to identify because it’s the result of a single and noticeable event. Cracks from a falling object typically radiate from the point of impact. The center point, where the brunt of the object struck, should be chipped, abraded, or fractured, and there may be smaller chipping around the edges.

ASTM International, an organization that develops technical standards for a variety of materials, indicates that ceramic tile must be able to resist a minimum force of 250 pounds per square inch. While a heavier or concentrated force may break a well-installed tile, an inspection by a licensed expert can determine whether a manufacturing defect or poor installation contributed to the damage.

Decay of the Floor Framing

Beneath tile flooring, fungal damage can fester on wood framing undetected. This moisture damage goes by many names, including “dry rot,” “wet rot,” and “wood rot.” When the wood becomes too soft to support the tile, the floor system can deflect (move downward), leading to damage that often manifests as cracks on the surface. 

Cracks start above areas most affected by decay and spread as the framing issues worsen and the tiles undergo normal use. Cracked tiles caused by deflection from fungal rot may be accompanied by a sagging floor and gaps at floor-to-wall interfaces or sealants.

390 Moisture Content Reading In Floor Framing

High moisture readings in wood framing below cracked tiles indicate a long-term issue that can affect the rest of the house if left unchecked.

Moisture and time are essential to fungal growth. A moisture content below 22% is considered safe, according to the University of Massachusetts, as wood rot often occurs between 25% and 28%. During inspections, experts should take moisture content readings and document visual observations to confirm whether decay is responsible for the cracked tiles. If so, a professional can locate the source of the moisture and recommend remediation to minimize the damage.

Differential Settlement

Differential settlement is when a structure doesn’t settle uniformly. Structures impose a weight load during and after construction, causing soil to compress and distribute this weight. While all structures built on soil experience settlement, the rate and amount vary based on construction practices and soil type. 

Damages to tile flooring from differential settlement are similar to those of decaying wood framing, as shifting building elements beneath the tiles affect their load-bearing capacity and can lead to cracking. These cracks are often accompanied by gaps between the tile and wall, or between tiles themselves as grout and mortar crack. On concrete slabs, reflective cracks in the tile often mirror cracks in the underlying concrete, and cracks related to settlement will be accompanied by vertical offsets.


This gap, found in a house with multiple cracked tiles, is a key indicator of differential settlement.

Improper Installation

Tiles installed according to ASTM International and Tile Council of North America guidelines should hold up to expected environmental conditions and usage. Several characteristics of cracked or otherwise damaged tiles can indicate improper installation techniques. 

First, laying tiles on an uneven or improperly prepared subfloor is an installation error, no matter how expertly the tiles are applied. The tiles are immediately vulnerable to small elevation changes throughout the structure, which is likely to lead to cracking from regular use. Not providing movement joints in the field of the tiles and against other materials leaves no room for expansion and contraction, which can cause cracking from pressure during unexpected temperature shifts. 

Improper adhesion leads to loose tiles, which can result in cracking as the tiles repeatedly impact one another or the underlayment beneath. Experts can diagnose poor adhesion by listening to the tiles; those that have come loose will have a hollow sound when struck gently. 

The cause of tile cracking almost always comes down to pressure. A licensed engineer familiar with tiles will use the evidence from an inspection to identify the cause, extent, and duration of loss, as well as recommend remediation steps upon request. 

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