No sealer in the Stone Care Product Industry can provide a tile or stone with an impenetrable barrier. Due to the absence of chemistry required to bond to the great variety of surfaces – in both porosity and texture – found in natural stone, sealers are unable to form an evenly gauged continuous film inside a tile or stone’s irregular core.
In other words the chemistry and sealing characteristics required to create a good sealer are different from those needed to create a good waterproof membrane. The bottom line is sealers are not waterproof or stain proof, and they will let things in at some point.
Sealers by nature are designed to allow vapour transmission and therefore at the very least enable vapour ‘gas’ molecules to migrate upwards through them. All stone and porous tiles must be allowed to breathe in order to maintain their structural integrity.
A stone or tile that is porous will enable staining immediately upon contact with a spillage. However if a sealer is applied, the liquid contaminants (such as wine, coca cola, coffee) are being held back and prevent immediate staining. This is because the sealer provides a sealing function, and water or other substances in their liquid form contain larger molecules than in their gas or vapour form. The amount of liquids penetrating into the stone or tile is thus reduced.
Any mechanism that reduces the amount of water entering the stone or tile will reduce the amount of salt that evaporates. More importantly the evaporation will be a more controlled event with smaller amounts of salt coming out thus decreasing the likelihood of Efflorescence and this result in easier maintenance.
Good sealers will achieve this by reducing porosity to very low levels. A poor sealer allows a short reaction time to a small variety of contaminants where a premium one allows much longer reaction time to a much greater variety of staining materials. By affording reaction time, they provide an invaluable service making tile and stone installations much easier to maintain which in turn extends the life of the installation.
However, do note that a sealer is only one part of a complete system that needs to be implemented to solve many of these water related problems. The installation of a waterproof membrane, dense latex modified mortars and grouts, washed sand, quality cements, pre-packed adhesives, the correct falls and drainage and a good sealer all combine will help to reduce the risk of water related problem issues.