Lap Tan Co., Ltd (Vietnam)


Efflorescence is often mistaken as dirt on the surface of stones. From timeto-time a homeowner makes every effort to clean their floor, only to find the task impossible. This is due to the white residue, which constantly deposits on the surface of the stone and seems to last forever. This white powdery substance is known as efflorescence.

Efflorescence mostly occurs in wet areas. The solution of mineral salt in water will migrate up to the surface of the stone, when alkaline salt is in the setting bed or stone and is dissolved by an excessive amount of water in or under the stone. As the stone dries out, the water evaporates and forms these mineral salt deposits. However, efflorescence does not always appear in a white powdery way. Often times, it may appear as a sticky cream-like form, due to the fact that the efflorescence does not completely dry and mixes with dust.

Before making any attempt to solve the problem, try to find and eliminate the original cause of the wetness under the stone. Normally, all that can be done is to use a dehumidifier, which allows the stones to dry. Then wipe off the excess residue with a dry cloth. Cutting off the grout with a tile saw does help the bed to try faster. Also, avoid using water for cleaning, since this will contribute to the problem. In many cases, it may take a very long time to eliminate efflorescence.

Our efflorescence treatment is designed to penetrate into the pores of the stone and replace the calcium or magnesium ions in the alkaline salt solution in order to avoid efflorescence forming. It is proven to be efficient after applying on different sites for many cases in Taiwan, but if the source of wetness is not blocked out, chances are the efflorescence will occur again after a period of time. It comes to the basic theory: Efflorescence is forming from excess of water and soluble salts. Since we cannot control the salts in the stones or the cement after the stone tiles are installed, the only way to stop its forming is to eliminate the water in/under the tiles. Any treatment, including ours, is only to help reduce the " symptom " of efflorescence as any medicine does for curing flu.

Efflorescence may not be a problem when it is forming after polishing, cleaning with water, or the tiles being newly installed. In these cases, it will stop forming after the tiles are totally dry, normally from 1 week to no more than 1 month. And during this period of time, it is obvious that the residue of salts are getting less and less.

Although efflorescence is not harmful to stone itself unless the alkaline salts stay on stone surface for too long, endless efflorescence growing is still a nightmare to house owners. Some contractors would suggest to apply impregnators to block its growing out on the tile surface. This is a useless and dangerous way to deal with efflorescence with impregnators. Impregnators are not alkaline or acidic resistant. They somehow occupy the pores underneath the stone surface, which may trap the salts migrating onto the surface. If the salts are deposit underneath the stone surface, the stone may spall or flake due to the expansion strength from crystallization of those salts. This is a harmful situation to stones known as sub-efflorescence.

When sub-efflorescence happens, the only way to bring back a smooth flat surface of a stone, is to deep grind the stone which is a time consuming work and will burn your money.

Written by,
Daniel Tai