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When does Stone need Sealing?


Granite is a natural construction. One piece of rock is not like any other on the planet. This is the one feature that actually makes this stuff so attractive and in demand. The uniqueness of each granite slab is what attracts a lot of homeowners into choosing to have a granite countertop / worktop.

This also means that no two granite slabs have the same porous virtues. If a natural stone is from one quarry, it would be comparable, but still exclusive. For instance, Black Galaxy from Brazil may not absorb anything, whereas similar black granite from Asia may be like a sponge in comparison. It does not matter where the stone is situated in your design, it can be a vanity top, kitchen worktop, fireplace surround, island top, or floor tile. If its natural stone, then there is a possibility it might need sealing.

What does that tell us? Not all natural stone like granite or marble will take a sealer. If a stone cannot soak up anything, even an impregnating sealer will not penetrate. Impregnating sealers sit below the surface of the stone and leave solid particles in the pores to coat the individual minerals underneath. This is excellent news, if a sealer won’t penetrate into the natural stone neither will a stain. One instance is the granite Ubatuba it’s does not seem to be that porous and more often than not does not need any sealing. Sealer usually does not penetrate this stone and is ineffective, leaving a hazy film on the surface.

This may astonish many in the countertop / worktop industry. If you were to go to any home show and ask a worktop specialist that sell anything other than natural stone worktops etc what makes their manufactured goods better than natural stone you will constantly get the same response. They will say that natural stone must be sealed every six months to once a year but their countertop surface does not need this bother.

So the need to sealing every granite, and sealing it frequently, is a fable and absolutely incorrect. This type of information is comes from fears and insecurities, or specially designed to prey on such concerns of homeowners. Everyone loves natural stone, but there is a certain air of mystery attached to it that unnerves the people who know not much about it. These shock tactics make granite owners fearful to do anything with their granite stone because if it’s ruined, it’s too costly to re new. The competition tries to pull away potential customers from getting a natural stone product by exaggerating the need for natral stone to be high-maintained when used in the home in the form of granite and marble countertops / worktops.

If this is the only supposed weakness of granite countertops for possible homeowners, it’s simple to extend the worry that all granite worktops need to be sealed. It makes good logic to them and is a persuasive reason for a homeowner to purchase a competitor’s or man made product instead of granite and other natural stone products.

In actuality, a small fraction of the commercially offered polished natural stone used for countertops / worktop vanity unit etc needs a sealer. A low fraction really needs to be sealed since granite is the major stone selection in use, and not all granites are fully porous. You can see this on something as simple as a granite rock in a garden or recreational area; after it rains; it does not stay wet for long and seems to dry. It dries right away.

Homeowners and fabricators can do the same at home. Put down water on a slab for 9-14 minutes and then take the water off the worktop if it doesn’t darken the natural stone when it’s removed, the granite will not soak up water based staining material. 

You can use a solvent test to see if a solvent- or petroleum-based stain will go into the granite. Simply apply some mineral oil on the slab and leave for 5-l0 minutes. Then remove it and it does not make the stone darker, neither will a staining product.

If it go’s dark, there are no fears about harming the granite as the mineral oil will evaporate, leaving the stone its natural colour. But, this will let you know that you can use a solvent-based sealer to guard against oil—based stains.

To recap, if the granite goes dark with either water or mineral oil, then seal. If there is no colour change with these two liquids, you don’t in reality need to seal your granite worktops / countertops.

This test works for granite and most all other natural stones, however there is a caution here with marble; an impregnating sealer won’t guard marble against horrible water rings.

They are not stains, no matter how much a customer would like them to be stains; they are etches or corrosion. It is a chemical reaction among the calcium in the granite or marble and the acid in the product that caused the etch.

Think of your favourite dress or shirt in the washing. If you spill water or oil on it, it goes dark. If it stays dark, it’s a stain. If it loses its colour, then it is bleached white, as the colour from the thread is removed.

On marble, the surface of the stone is tarnished, leaving the stone in its real natural state or its unfinished look. No quantity of sealer will help to get the colour back; it will need to be resurfaced.

It’s also imperative to point out that this applies to commercially accessible polished natural stone. When a stone is polished, the pores are more together and limit the capacity of liquids to go into the stone. With a honed finish, liquids can enter more easily and consequently these tops will need an impregnating sealer.

One of the most popular questions is, once you determine if you are going to seal your granite, how often to do so? The answer to this is simple: When your countertop is no longer repels water or oil. If you notice, after washing the dishes, the stone is darker with moisture and then be coming lighter a little time later, then it’s time to re-apply with the same sealer first used.

Trustworthy fabricators like the worktop factory value their customers and will seal marble and granite that needs sealing before and after installation. They also show the homeowner how to correctly seal natural stone so their are no misshapes made in the future. A good sealer should last about 5 years, even with some of the most porous of natural stone. As far as the ambiguity of sealing natural stone: Seal when necessary, and try to use products that do not involve repeated applications. With natural stone more is not always better.

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