In addition to countertop care and maintenance, one of the most common questions we hear is whether natural stone countertops need to be sealed. Ask three people whether you should seal granite countertops, and you’ll get three different answers.
As it turns out, there’s a good reason for this range of opinions. Not all stone countertops need to be sealed. Some types of granite, like Ubatuba granite, for instance, is so dense that it won’t absorb anything anyway. It has a very low absorption rate and a low chance of staining.
However, the vast majority of natural stone countertops do need to be sealed once in a while. This is particularly true of counters with a honed finish. For these stones, sealant plays a vital role in keeping your countertop resistant to stains. A sealant also makes it easier to keep your kitchen countertop clean and looking good.
Properly sealing natural stone is important because most stones are porous — Quartz, which is engineered from natural stone, is the exception to this rule. Porous stones have small channels or pores in the rock, which are usually filled with air. An extreme example of a porous rock is pumice stone, where air channels are clearly visible.
The porosity of a stone is influenced by the number of channels, or micro-voids, in the stone itself. Granite has a reputation as a particularly non-porous stone. Marble is usually more porous.
In countertops, these channels are much smaller. However, their presence means that food or water can seep into the stone, leaving stains. By using a sealer or impregnator on the stone, you’ll prevent liquids from seeping into the counter.