Contrary to marketing slogans and advertising slogans, there is no universal product that will work in every case. This also applies to the product, which is tile adhesive. The adhesive is selected according to the substrate, installation location, tile format, stresses, ambient temperature and many other factors. That is why its choice should be well thought out.
Parameters of tile adhesives
Glue adhesion
The most important property of an adhesive is its adhesion. This parameter divides adhesives into two groups: C1 and C2. All adhesives with a minimum adhesion of 0.5 N/mm 2 are classified in the C1 group , while the C2 group includes adhesives with a minimum adhesion of 1 N/mm 2 . Often on the packaging of adhesives you can also find the definition of real adhesion. This information is usually provided for higher priced adhesives.
C1 class mortars are successfully used on the surfaces of most plasters and screeds. C2 mortars can be additionally used on such substrates as: terrazzo, ceramic cladding, OSB boards, PVC boards soiled with old glue, extremely smooth, extremely dirty surfaces or those with minimal water absorption.
Glue deformability
Formability is a parameter that determines to what extent the cured adhesive is susceptible to deformation resulting from the stresses that appear between the laying surface and the tiles. In terms of deformability, adhesives are divided into class S1 – deformation in the range of 2.5 – 5 mm, and class S2 – deformation above 5 mm.
S2 class adhesives are used in places exposed to large deformations, usually caused by external factors, such as temperature differences and mechanical stress. Therefore, deformable adhesives can be used for gluing tiles on balconies, terraces, for floor heating, on facades, for fireplaces, on wooden ceilings, plasterboards or partition walls.
Self-flowing
The property of the mortar desired mainly in the case of laying large-format tiles and for fixing tiles on uneven substrates. Thanks to self-spreading, the glue spreads evenly, tightly filling every gap in the substrate. In this way, it displaces air and water from the space between the tile and the substrate, which ensures full support for the tiles. Self-flowing adhesives facilitate the leveling of tiles, and also improve the degree of protection against damage to tiles caused by impacts and pressure.
frost resistance
The frost-resistant adhesive is resistant to long-term exposure to sub-zero temperatures without changing its properties. Frost-resistant adhesive mortars should be used for gluing tiles outside buildings – on terraces, facades, balconies, as well as anywhere where tiles are exposed to temperatures below zero, e.g. in freezers.
Basic symbols defining types of tile adhesives
On the packaging of adhesives, we can find three markings specifying the type of adhesive mortar. These are the letters C, D and R.
C adhesives
Adhesives marked with the letter C are cement-based products. These are the most popular adhesives successfully used on most easy surfaces. Before application, cement adhesives should be diluted with water.
D adhesives
The letter D defines dispersion adhesives, which are dedicated to laying tiles on surfaces covered with glaze and on KG boards. This type of mortar consists of mineral fillers and organic joints and does not require mixing with water.
R adhesives
Adhesives marked with the letter R are products based on reactive synthetic resins and mineral and organic fillers. This type of mortar is used for gluing tiles on polyester, substrates made of synthetic materials, metal, ceramics and polyvinyl chloride.
Symbols defining the characteristics of tile adhesives
On the packaging and in the technical notes you can find enigmatic letters that, apart from specifying the type of glue, inform the user about the features and properties of the product. Below we present the most important of these symbols.
T – thixotropy
This letter indicates that the adhesive has a reduced flow. The property of thixotropy is desirable when installing tiles on walls. The maximum runoff is about 0.5 mm.
F – fast setting
Quick-setting adhesives are dedicated to fast and undemanding laying of tiles, especially when working at lower temperatures.
E – long open time
This type of mortar binds longer, which makes it possible to level and level the tiles more precisely.
Number 1
A number specifying an adhesive with a standard setting time.
Digit 2
A number indicating the degree of a given property, e.g. 2F glue will set faster than the glue marked with the letter F.
