natural stone sealing

natural stone sealing

Impregnating Stone Sealers

The proper way to seal stone is called impregnating. This is a method which uses silicone or fluoro-carbon type resins made soluble in liquid carriers either water (water-based), petroleum, aromatic, and aliphatic (solvent-based). The impregnator is applied to the stone and soaks into the surface. The base (carrier) then vaporizes and the resins remain in the stone to cure.

This method of stone sealing does not fill the pores of the stone and will allow the moisture to transmit. Moisture transmission (breathing) is very important for stone to prevent problems such as spalling (flaking), oxidization (rusting), and efflorescence.


It is a matter of some debate whether all stone needs to be sealed and most of the time it does help. In some cases, it does not make much difference. In a few cases, it can actually be harmful to the stone.

In many cases, the stone absolutely needs to be sealed. It all depends on the stone which it will be applied to and if it’s a suitable type. Some stone sealers should only be applied in interior applications, and some stone sealers only used externally.

For more on this you can read this excellent article on our blog:

bathroom tile

Colour Enhancing Impregnators

Colour enhancing impregnators are stone sealers designed to enrich the natural colours and will provide an aesthetic result. These enhancing sealers do a wonderful job at making old and dull looking stone come back to life, or add even more character to certain stone types like slate, sandstone, quartzite, and granite. True enhancers will not leave any surface film and will allow the stone to breathe.

Some so called “enhancers” are really just solvent based acrylics. These are a cheap imitation and not a suitable option for most stone types. The drawback with enhancing impregnators is that they can sometimes fade with UV exposure. We have found that some brands are better than others. With the correct application methods, we can ensure the longest possible effect.

shower stone sealing

Impregnating Stone Sealers

We take great care in specifying the correct sealer for each application, to make sure you get the greatest effect and long-lasting results. The products we use are of the highest quality from the best suppliers in Hawaii, and overseas. Our application methods ensure the deepest possible penetration of the resin solids into the stone, often “layering” two types of sealers in a specific order, to guarantee the stone will be sealed from all types of contaminants, both water and oil born.

Stone Coatings

Stone coatings are usually coatings that are not stone coatings at all, meaning that they are usually not produced as “stone specific.” These coatings are general purpose, that is also marketed as suitable for masonry, and sometimes stone. The coatings have solids of either acrylic, urethane, or more sophisticated blends sometimes requiring a catalyst.

It is my opinion that coatings because they will not allow the stone to breathe naturally, are usually not suitable for stone. Of course, there are exceptions to every rule. Coatings should only have to be used when a stone is specified for use in an unsuitable environment, and maintenance will be too difficult otherwise.