Tiles: how to avoid damage to tiled floors
Batirama.com 13/09/20210The latest AQC report* shows that interior floor covering pathologies are at the forefront of the Flop 10, in terms of number and repair cost. Here is a reminder of some recommendations.
Caption: deterioration of the joints of the tiled floor
No surprise, the pathologies of ceramic coatings remain one of the most recurrent in the flop 10 recently published by the Construction Quality Observatory (1). If the abundant normative corpus (DTU, professional rules, see box) is constantly evolving, it will probably take a few years before observing a regression of these pathologies, with the modification of practices that will induce the evolution of reference texts. .
According to Jean-Pierre Thomas, deputy technical director of the Construction division of the Stelliant group, these pathologies generate average repair costs of 11,000 euros in residential homes.
Compared to the cost of building a detached house (from 100,000 euros for first-time buyers), this repair cost is significant (10% of the cost of the house).
Inadequate residential support in 40% of cases
The detailed data on the pathologies come from an AQC report carried out by Jean-Pierre Thomas 4 years ago. This work (Sols carrelés - Points de vigilance) analyzes 428 expert reports covering 333 files, over a period of 12 years. The period for declaring these claims is indeed particularly long and varies from 6.1 years after receipt for glued installation, to 7 years for sealed installation.
More than 40% of cases are due to an unsuitability of the residential support (screed, floor, old covering), underlines J.P. Thomas. Another lesson: more than one in three cases concerns insufficient bonding or sealing in non-residential buildings. Finally, one out of four cases concerns an absence or insufficiency of seal.
Other information: 90% of pathologies concern residential buildings, half of them in individual housing (43% glued installation, 37% sealed installation) and the other half in collective housing (66% sealed installation).
The size of the tiles has no impact on pathologies
The expert notes that the size of the tiles has very little impact on the observed loss experience, as does the type of tiling (terracotta, enamel, porcelain stoneware, etc.). Similarly, the presence or absence of a heated floor or the weather conditions of implementation are not loss factors.
On the other hand, the conditions of implementation are more involved in claims. And these pathologies take three main forms, including cracking in 64% of the cases studied. The two other forms concern, on the one hand, detachment (loosening and lifting) and, on the other hand, the surface degradation of the tiles, the deterioration of the joints between tiles, slippage, etc.
Cracking of tiles is mainly related to sealed installation
Thus, cracking of tiles (64% of cases) is a pathology affecting three times more the sealed installation than the glued installation. Indeed, it was noted in 49% of the cases of the glued installation but also and especially in 92% of the cases of the sealed installation (i.e. 44% of all the cases studied).
A few explanations on cracking: it is caused by the slow (and even very slow) differential shrinkage of the mortar for laying the separated sealed tiles (increased by its thickness). This shrinkage favors its shortening in the lower part while it is thwarted by the adhesion to the tiles in the upper part. The delay in appearance of the phenomenon is linked to the loss of water from the mortar, which can only occur very slowly by evaporation alone through the tile joints.
As a result, this shrinkage generates a shearing force, known as the "bimetal" effect between tiles and support, and a bending force in the tiles, hence their breakage (effect of bending of the sealing mortar and of the coating, up to to cracking).
Note also that the sealed tiles can be laid on an insulating underlay (intended to dampen the impact noise associated with walking on the hard surface). However, the shrinkage and bending of the mortar bed can perforate the insulating underlayer and generate the appearance of sub-plinth voids on the periphery.
Cracking and overdosing of cement and insufficient fractionation joints
Two factors can increase this phenomenon of amplified shrinkage and therefore cracking: cement overdosage (a reduction in dosages has been planned in rooms P2 and P3 in DTU 52.1 since 2010) and exposure to sunlight (facing to a south-facing French window, for example).
Note that the effects are increased in the absence or insufficiency of division joints (especially at the thresholds or at the re-entrant angles) or of peripheral joints. Shrinkage results in a shortening of the laying mortar, the effect of movements of which can be partly compensated at the level of the splitting joints, which are therefore truly necessary.
Another practice that can accentuate the cracking of the tiles: the absence of implementation of a ravoirage to incorporate the pipes which will locally weaken the thickness of the seal and its resistance.
Removal of glued tiles
Other pathologies: detachment of tiles in glued installationAssociated more than 80% with glued installation (4.7 years on average after installation), tile detachment can be due to:
Note: Be careful not to spread the damage! As specified in appendix B of DTU 52.1 P 1-1 and year A of DTU 52.3-2 P 1-1-3), the damaged tile must not be left as it is. It is indeed essential to repair the area concerned as soon as a defect is observed, in order to avoid an extension of the damage.
Double gluing is required on this type of large format tile (over 60 cm x 60 cm) whose laying on the floor only concerns rooms classified at most P3 and E2 (without floor drain). The flatness of the support is limited to 3 mm under the 2 m ruler and 1 mm under the 20 cm ruler. The DTU recommends a fluid cement or sulphate screed under Technical Assessment or Technical Application Document, a traditional screed (DTU 26.2), a concrete slab + QB certified floor coating. These tiles can be laid on a hot water heated floor (NF DTU 65.14) or reversible with synthetic material pipes under certain conditions. Note for smoothing, tiles beaten, pressed and even better vibrated. |
Tile floors: many standards to know
For other configurations
Normative texts relating to media
Also noteworthy for wall tiles, the recent publication of Professional rules Laying glued ceramic coverings large format, very large format, and oblong format in interior walls in new works of January 2021, accepted by the C2P, which makes enter this pose into the current techniques recognized by insurers. |
*The construction quality observatory has collected 2020 data from the four observation systems of the Construction Quality Agency (AQC), including the Sycodes system (report by experts called by insurers during the implementation implementation of Property Damage insurance).
Source: batirama.com/ Fabienne Leroy
