Many times, when reading literature concerning technologies for performing tile work, as well as when communicating with master tilers, I came across the concept of an expansion joint. There are also the concepts of dilatation seam, expansion seam, expansion seam, moving seam... It seems to me that these are different concepts, but often an individual “master” uses one term in all cases. I ask my colleagues to join this topic, bring clarity to it, indicate when and how to carry out this kind of stitches, and increase our overall level of competence.
Expansion joints are a generalized name for all types of movable joints. In wall cladding and floor coverings, several types of seams are distinguished in accordance with their functional purpose - separation, temperature , adjoining seams .
Separation joints are structural expansion joints. They pass through all load-bearing and non-load-bearing parts of the building. Such joints must be of sufficient width in external and internal cladding or floor coverings and at joints of building structures (walls, supports).
Expansion joints - placed deep into the cladding by one third of the thickness of the cement layer, dividing large veneered surfaces into sections. Thus, they are most often found in large areas (commercial facilities, airports, train stations). In private construction they are less common.
Joint joints are usually installed between the cladding or covering and other building structural parts, for example, at the junction with a support, window unit or floor threshold.
Expansion joints are breaks in the structure that allow sections to move independently. Expansion joints are breaks in the structure that provide compensation for internal stresses in the structure of hardened mortar or concrete that arise during temperature changes. Shrinkage joints are breaks in structural elements that prevent the occurrence of chaotic cracks during the hardening of the solution.
Expansion joints are gaps in the tile covering and mortar.
They are filled with a resistant, elastic material that absorbs the stresses arising in the structures, ensuring the durability of the tile covering. the number of expansion joints in the coating should increase with: - increased temperature and humidity conditions;
-- in cases where the supporting structure is easily subject to deformation;
-- more rigid tile covering (narrow-seam).
Recommended size of the area limited by expansion joints (EN standards): in buildings (narrow-seam pavement from 4x4 m to 6x6 m; wide-seam pavement from 6x6 m to 10x10 m); on the street (narrow-seam coating from 2x2 m to 3x3 m; wide-seam coating from 3x3 m to 5x5 m).
The dimensions of dividing joints are determined by architects and designers, and the dimensions of expansion joints and abutment joints are determined by tilers. The width of expansion joints must be at least 8 mm, and the width of junction joints must be at least 5 mm.
When making screeds from cement-sand mortar and floor mixtures with cement binder, shrinkage joints must be provided in the longitudinal and transverse directions in increments of 3 to 6 meters. The seams must coincide with the axes of the columns and the installation seams of the base. The seams must have a depth of at least 1/3 of the thickness of the screed and a width of 3 to 5 mm. The seams are cut using concrete seam cutters or angle grinders approximately 1 day after making the screed.
Once shrinkage is complete (approximately 2 weeks after laying the screed), shrinkage joints must be sealed with a suitable floor or repair mixture.