17 August 2016

Almost all granite sealers work in the same manner. However, there are a lot misunderstanding and misconceptions when it comes to how they work. One of the most common perceptions about sealers is that they prevent the stone from damage or staining. This is absolutely false as granite benchtops can still get stained or even damaged when sealed. All that a sealer does is to reduce the absorbency of granite.

How sealers work

• Also known as impregnators, sealers are made of a resin dissolved in petroleum based solvent or water

• Sealers are applied onto the stone and left to sit. This allows the sealer to be absorbed into the stone pores, hence the name impregnators.

• Resin is used for the purpose of clogging the pores of the stone. All excess sealer is wiped and the solvent evaporates enabling the resin to harden.

• The sealer increases the amount of time that spills sit on top of the stone before getting absorbed. This gives you time to wipe them off, thus keeping your granite benchtops clean.

As stated previously, sealing granite benchtops does not mean that staining won’t occur. It does occur, although on rare occasions. But why would staining occur in a sealed granite benchtop? There are several reasons for this. These are outlined below.

• All stones are porous. The degree of porosity differs from one stone to another

• While a sealer clog pores to reduce the rate of absorption, not all pores are clogged

• The protective quality depends a lot on the quality of the sealer used as well as the quality of the application process

• Prolonging moisture on granite countertops can also cause staining of granite benchtops

• Since oil does not evaporate, it tends to stain the stone if not cleaned soon enough

• Staining will also occur if granite is not sealed as frequently as it should

It’s important to remember that stones in the same commercial family do not necessarily perform exactly the same. As such their sealing needs vary. It’s important to perform the lemon juice and oil test to gauge your stone’s sealing needs.

Sealing and etching

People often mistake glass rings and water spots on granite benchtops for stains. These are however not stains as nothing dissolves into the stone for them to be formed. As a result, there is no connection between sealing and etching.

Etching usually occurs on calcite based stones such as limestone, marble and travertine. These stones react with acids in juices, coffee, vinegar, alcohol and etc. that come into contact with them. Etching corrodes the surface of the benchtop, distorting its appearance. This happens in a matter of seconds and while it may not always be visible, don’t assume it hasn’t happened.

How often should you seal your granite benchtop?

The porosity of different granite stones and sealer quality obviously vary. However, most granites require sealing every 3-5 years and sometimes every ten years, depending on how well it is cared for. The sealing time will vary for other stones will vary as well. Using the water test will help you determine whether it’s time to reseal your granite benchtops in Perth.