Bonding a tile that has fallen off the wall back into place is not the easiest job. Remains of adhesive or mortar are left on both the wall and the tile, the surface is not particularly even, so the adhesive has to be one that works well on uneven surfaces and has excellent adhesion to a wide range of materials. Construction adhesives — “liquid nails” — are a good solution, but not all of them are equally good for this job.
Hybrid polymers work best
The best product for bonding tile is a hybrid polymer adhesive sealant from the KUDO® “HANDLE ALL” or NEXTGEN range. For floors either of them will do; for walls HIGH TACK is the best choice. HIGH TACK has the highest initial tack, so a tile with adhesive applied to it only has to be placed against the wall and pressed for a few seconds, and it will not come off again. A very large and heavy tile may need extra support against sliding down, using spacers in the tile joints.
It is better to grout the tile joints 2–3 days after bonding: that is how long the adhesive sealant needs to cure fully.
Hybrid polymer adhesive sealants have a number of benefits:
- Primerless adhesion, no priming required
- Excellent adhesion to almost all materials
- Undemanding application conditions, they bond even under water
- Chemically neutral to any surface
- Do not crack over the whole service life
- Isocyanate-free and solvent-free
- No post-expansion and no shrinkage
- Very durable, with a service life of more than 25 years
Synthetic rubber adhesives
Synthetic rubber “liquid nails” can also be used to bond a tile that has fallen off. They are, however, usually less convenient to work with than hybrid polymer adhesives.
A synthetic rubber adhesive can be used with the double-stick method: apply the adhesive to the tile, press the tile against the substrate, then pull it away, wait a while and press it into place again. Used this way, the adhesive grabs almost immediately. Once the parts are joined, though, the position of the tile can no longer be corrected, and for the first 24 hours the bond line should not be put under heavy load.
With the ordinary application method every tile has to be held in place longer, especially a heavy one. Synthetic rubber adhesives are also noticeably less elastic than hybrid ones. They cope worse with the repeated compression and tension cycles caused by walking on the tile, so such a bond may have a shorter service life.
Acrylic adhesives
Acrylic “liquid nails”, low as their price is, are the least suitable for bonding tile. Their strength and adhesion are six to seven times lower than those of hybrid polymer products, and they are not intended for use in wet rooms.
Foam adhesive
For bonding large quantities of tile, foam adhesive can also be used: it has excellent adhesion and fairly high strength. In repair work, however, it has to be kept in mind that foam adhesive has a post-expansion of about 10–20%.
