Tiles: problems and pathologies

Problemi pavimenti in piastrelle: sollevamento di una piastrellatura

What are the problems that can occur when buying a ceramic tile floor? What diseases can ruin a tiled floor? And, above all, how can these problems be anticipated and avoided? 

These are the questions we will try to answer in this article where we will explain: 
► The difference between a real problem and a failure to meet expectations
► The difference between tile problems and tile installation problems
► Problems that occur immediately and those that arise over time

Here is the list of problems - long but not exhaustive - that we will address:

At the end a photo gallery of "nightmare floors".

We do not claim to have managed to clarify all the problems that can occur on a tiled surface or on an individual tile. Should your case not be among those listed, please write to us and - if of general interest - we will post the answer here. 




Problemi di comunicazione

The first category of problems that can arise when buying a tile floor concerns false expectations, lack of communication, misunderstandings, lack of on-site checks... in short, small omissions in communication or misunderstandings that can cause small but also big problems. 

1.1 Incorrectly arrived tiles

Problem: Tiles are different from those ordered

problemi piastrelle arrivate sbagliate

The first case is when tiles are delivered that are completely different from those ordered. Please note that this is not a different colour, but a genuine mistake when ordering the chosen product. 
What happens if you realise the mistake when the wrong tiles have already been laid? Who is liable for the damage? 

tiles different from those ordered


1.2 Tiles that look wrong

Problem: Tiles "look" wrong

Problemi piastrelle: sembrano sbagliate

It can happen that a customer perceives a clear difference between the chosen tile and the delivered tile even though the tile was correctly ordered.
This may be due to the lighting being too warm or too cold in the shop, which is different from the lighting in the house.
Or it could be that the samples are placed vertically in the shop, which will cause the tile to be perceived differently from the horizontal arrangement in the home.
Finally, it can be the well-known problem of tones: each production batch differs from the previous one by a small difference in tone. 
In the following article we will discuss these and other aspects that can lead to false expectations and disappointment: 

tiles that look wrong


1.3 Insufficient tiles

Problem: Not enough tiles ordered

Mancano piastrelle per finire il lavoro

An insufficient quantity of tiles may seem like a trivial problem... but it is not.
In addition to the inconvenience of having to suspend work and having the tiler come back, there is the risk of not being able to find a tile of the same tone as the one you have already started to lay. 
In this article we look at the causes and what you can do to avoid this problem.

insufficient tiles: how to avoid this risk



problemi piastrelle conformità

The second category of problems concerns defects - real or presumed - that the client reports relating to the tile or tiling once it has been completed.

2.1 Non-planar, uncalibrated, crooked tiles

Crooked tiles, non-planar, with non-orthogonal edges

Problem: the tile is not flat!

problemi piastrelle planarità

We have to distinguish between tile and tiling: the tile is the single element, while the tiling is the floor composed of the different tiles once they have been laid and grouted.

Piastrella con difetti di non planarità
These tiles appear to have a defect at the end which has a rise. However, visual inspection, especially if carried out against the light (this is forbidden by the Uni standards), is not sufficient to determine the defectiveness of the floor. An on-site measurement must be carried out in accordance with the Uni En Iso 10545.2 standard.

In this paragraph we will talk about non-planarity referring to a single tile. 

Problemi delle piastrelle: la planarità
Two tiles juxtaposed in the face show a non-planarity (convexity)


It may happen to be faced with a batch of tiles in which some or all of them present a non-planarity defect. This means that individual tiles may have a concave or convex surface (or portion of surface). An example of this is the photo above, where two tiles laid together reveal an obvious convexity. It is difficult to lay tiles with such obvious defects without compromising the final result of the floor.

Piastrelle storte
The concavity can refer to the whole tile or the defect can occur in one area of the tile, as in this case.

There is a defined tolerance for tiles, expressed in the Uni En Iso 10545.2 standard, which defines up to what values a tile can be considered flat and when it must be considered defective. 

>>>Flatness of ceramic tiles>> [in preparation].


Tile edges not straight ("not square")

Another similar - and equally important - problem is the non-orthogonal tile edges. In order to be laid correctly, the tile must be a square or a rectangle with all corners at 90°. If, on the other hand, it is a trapezoid, it cannot be laid.
This type of defect is unlikely to occur, but has happened to us more than a few times. This anomaly originates during the tile grinding phase, when the product is loaded incorrectly into the grinding machine.
The installer notices this problem immediately, as soon as he starts laying, and we advise him not to proceed but to stop, to check with a square how many tiles have the defect: if they are few they can be used for perimeter cuts and then the floor can be laid, while if they are present in a significant percentage it is necessary to ask for the replacement of the whole batch.

Examples of tiles with non-square edges

If you click on the image to enlarge it, you will see how the metal square detects that the sides of the tile are not orthogonal.


Non-calibrated tiles

In order to be able to combine tiles of different colours or sizes, they must have the same size. That is, the sides must be the same size. This is not as trivial as it may seem. Tiles are produced in a kiln and their size decreases as they are fired. For this reason, tiles are assigned a "gauge" - generally a number ranging from 0 to 9 - which identifies homogeneous widths.
Tiles of size 0 cannot be laid together with tiles of size 4, for example. When buying tiles of different colours, it must be specified that the project is to lay the two colours next to each other, and therefore require them to be of the same gauge.
In the example below the two colours have different gauges. The problem may not seem very obvious, but after a certain number of tiles the difference in alignment is noticeable.

Examples of tiles with different gauge


2.2 Non-flat tile flooring

Problem: the tile is not flat


pavimento in piastrelle non planare


What if the tile is level but the tiling is not level? 


This happens much more often and is one of the most frequently encountered problems. What happens is that the project manager or the client signals the presence of differences in level between one tile and another, the formation of "teeth" in correspondence with adjacent tiles. 
We have dedicated a specific article to this, click here to read it:

Differences in level between tiles, what are they, what do the standards say and how to avoid them?


Once again, it is extremely important to ensure that the screed is laid correctly and that the substrate on which the tiles are to be laid is perfectly flat. An uneven substrate will only cause other irregularities in the tiled surface

Tiling flatness depends on the screed

If we have to lay thin stoneware (large laminated stoneware slabs), checking the regularity of the substrate becomes even more important. The Uni 11493 standard assigns the construction manager the task of checking the flatness of the screed. For our part, we suggest that the installer should also carry out an accurate check before laying and that, in the event of serious irregularities, he should refuse to lay the floor if this is not remedied.

The technical literature in the sector shows that the client is usually much more sensitive than the levels required by the standard. It is clear that in the event of a dispute, the standards apply, but in order to achieve customer satisfaction, we (and many others in the industry) try to work to better quality levels than those prescribed.

Problem: non-planar tiling, some examples

2.3 Size of irregular joints

Problem: uneven tile joints

problemi piastrelle: fughe irregolari

Another of the problems that can arise when the work is completed is the different size (width) of the joints. 
There are two main reasons for this:
► tiles that are not perfectly calibrated (different side measurements from one tile to another)
► insufficiently accurate laying or without the use of equipment to adjust the size of the joints. 
► incorrect design (jointed laying instructions, or rectangular tiles offset by half).

We discuss this in detail in this article:

Problem on a tiled floor: joints with different widths

We receive frequent questions on this topic, such as this customer's question:

FAQ: tiles with uneven joints, i want a redo!

Examples of irregular or incorrect joints


2.4 Tiles with blotchy, discoloured joints

Tiles: the problem of "patchy" joints

Problema piastrelle fughe chiazzate

It can happen that once the tiles have been laid, the grout can become "blotchy", with lighter colours in some places and darker ones in others. 
The causes may vary, as does the extent of the discomfort, which may be barely noticeable or may jeopardise the aesthetics of the floor. 
In this article we examine the causes, see how to avoid this problem and propose remedies:

Problems on tiles: stained joints

2.5 Stains on tiles after installation

Problem: stains on tiles

Problemi piastrelle: macchie dopo la posa


When the floor is handed over, i.e. after the tiles have been laid and grouted, the construction manager is given the task of checking the tiling. One of the things that must be checked is whether there are any persistent stains. 
What are the causes of these stains? How can they be removed? We discuss this in this article:

stains on tiles after installation

2.6 Quibble on the tile

Problems on tiles: the quibble

Problema delle piastrelle, il cavillo


A quibble is a small crack, a superficial lesion that is sometimes more visible, somtimes almot invisible.It is not always a defect, sometimes it is a sought-after effect. But in some cases it is a defect that can occur even months after installation. 
Find out more about this problem by clicking here:

Ithe crack in the ceramic tile

Tiles cracked after installation

2.7 Tiles singing empty

Tiles problem: singing empty

Problema di piastrelle che cantano a vuoto

Why do the tiles sing hollow? What are the causes and what does this symptom lead to? 
We tell you all about it in the article:

>>>Tiles that sing hollow>> [under review].

2.8 Joints are lower than the tile

Tiles: the problem of low joints

Piastrelle: il problema delle fughe troppo basse


The client may complain that the joint is lower than the tile.
No matter how good the installer may be at applying cement grout and cleaning the floor after grouting, it is impossible for the joints to be at the same level, at the same height, as the tile.
It is impossible to have a continuous surface, in short. It should be borne in mind that grouting is water-based, and simply evaporating the water will lead to a physiological drop

2.9 Jumping leaks: stucco coming off

Joints getting damaged, pieces of grout coming off

As you can see in the three photos in the gallery below, another problem that can occur is the detachment of small pieces of grout from the joints

Fughe fatte male

In these cases it is important to determine the cause of these loose joints.
It could be a movement of the floor due to micro-slumps in the building, or it could be that the tiles are detaching from the substrate or that the perimeter and fractioning joints have not been correctly executed or sized. 

Once the causes have been resolved, the joint will be removed using a special diamond brush and then the tiles will be grouted again. 

Damaged leaks in floor and wall tiles

2.10 Badly made cuts

It may happen that the customer notices tile cuts at sockets or sanitary fittings that have been badly made. The most frequent causes are

  • the use of incorrect tools
  • incorrect positioning of the hole on the tile with respect to the installation element
  • incorrect sizing or lack of orthogonality of the hole or cuts
problemi nella posa delle piastrelle: taglio errato in corrispondenza di presa elettrica
In some cases the cutting errors are gross...


2.11 Bad starts

Another common mistake is to make the wrong "start" when laying tiles. The error consists in deciding badly where and how to start laying the tiles, with the result that you end up with irregular or unsightly cuts on the opposite side.

To avoid these situations, it is necessary to simulate the layout of the tiles when they are dry in order to calculate where and how the joints fall. At the same time, the out-of-squareness of the walls and other immovable elements (stairs, pillars, chimneys) must be checked in order to take into account any diagonal cuts and "slices" of tiles that would then have to be laid.

2.12 Tiles and defects: craters

The presence of one or more "craters" on the surface of the tile is generally due to the presence of impurities in the clay mixture. These impurities can generate small explosions during firing. If they occur close to the surface of the tile they generate small craters which are considered defects.

Piastrelle con difetti
A "crater" on the surface of the tile

This type of defect is generally detected by quality monitoring systems, so it is quite rare for a material with such a defect to arrive at the construction site, but if it does, the construction manager must not lay it.

Examples of wrong tiling starts



A third category of problems concerns the durability of the tiling over time, which can be compromised by various factors. 


3.1 Broken and loose tiles

Problems with tiling: breaking and lifting

problemi con le piastrelle: rottura



Tile breakage can be caused by a domestic accident (A), such as falling heavy objects, but it can also be due to the detachment of the tile from the screed (B). Once detached, the tile is much more fragile and does not withstand intense mechanical stress. 
The causes and precautions to avoid this are the subject of a specific article, the link to which is provided below.
In advance, the remedy is to replace damaged tiles, which can only be done if the customer has kept spare tiles

lifting tiles


3.2 Toxic tiles

Problems with tiles: toxicity and radioactivity

Piastrelle tossiche

There have been cases in the news where tiles have been found to have abnormal radioactivity or to contain toxic or harmful substances.
Using tiles intended for private homes to 'dispose' of toxic waste or incinerator residues is criminal, but unfortunately it does happen. 
These are all cases of tiles that are not produced in Italy, but come from South East Asian countries. 
The low purchase price, the lack of certifications, the unknown brand... are all clues that should set off alarm bells.  

toxic tiles

Gallery of errors