01 Aug Executing joints on facades
Joints between tiles constitute the natural separation therebetween and are called tile-to-tile joints.
Tile-to-tile joints fulfill two basic functions:
Technical: Reduce aggressions due to substrate movements and stresses, and improve tile adherence.
Furthermore, they prevent the accumulation of water on the substrate and the appearance of pathologies.
Aesthetics: Their correct application in terms of width, color and execution improves the decorative image of the surface clad with ceramic, stone material or mosaic.
The use of a biocidal preservation system prevents the appearance of molds and other micro-organisms.
Preliminary analysis
Different factors can affect ceramic cladding:
- The deformation of the substrates.
- Climate and atmospheric aggressions (rain, frost, thermal shock, etc.).
- The size of the tiles. Considering that an excessively large size has less possibility of absorbing movements by the joints destined for such end.
- The colour of the coat, as very dark colours are susceptible of accumulating and absorbing a larger amount of solar radiation.
Therefore, the use of deformable joint adhesives and mortars is advisable.
The application of joints in exteriors should have a width greater than 5 mm in all cases.
Technical considerations
We must take into account the design of the joints between tiles and the need to respect all the expansion joints of the façade.
Joints between tiles will be determined by the size and type of the ceramic tiles:
- Conventional ceramic: from 5 to 8 mm.
- Extruded ceramic: from 5 to 10 mm.
- Stone material: from 5 to 10 mm.
It is obligatory to leave movement joints on any structural joint of the building.
Likewise, perimeter movement joints in corners and changes in plane, height or material, as well as the movement joints that constitute maximum surface areas of 25 m2.
In the case of dark-colored tiles (due to the greater absorption of solar radiation), surface areas no larger than 12 m2 shall be constituted.
In all cases, movement joints will be filled with elastic sealants of the G#color Elastic-MS type and be 10 mm in width, reaching up to the substrate.
Before grouting, make sure that the ceramic tiles have been placed correctly and that the tiles are perfectly anchored to the substrate.
When grouting, observe the wait time indicated on the Technical Data Sheet of the product used, as possible rising water or damp may form salt deposits on the surface of the tile-to-tile joint or changes in color, spoiling the desired aesthetic effect.
Joints must be clean of dust, friable parts and adhesive residue. They should be of uniform depth, at least equal to 2/3 of the total coating thickness.
This prevents drying differences caused by the different thicknesses and, consequently, obtaining different colors throughout the execution thereof.
Mix the product with clean water, being careful not to add too much water, as it would cause a reduction in mechanical strength and/or aesthetic problems on the joint surface.
Perform the final clean-up using a damp sponge, not wet, to avoid dripping water and changes in the desired colour.
After 24 hours have elapsed, rehydrate using a damp sponge.
This will ensure the correct hardening of the product and a homogeneous colour.
Recommended products
Joint mortars
Flexible mastic
Warnings: The data provided by this Constructive Solution were prepared based on standard onsite installation processes. However, we recommend that you consult our Technical Department in the event of any specific circumstance info@gecol.com