How To Seal And Protect Natural Stone

Natural stone is a beautiful material that can transform the appearance of your home or place of business.

Each piece of natural stone has a unique combination of grain, colours, and patterns — which can set your property apart.

It is also durable, easy-to-clean and environmentally friendly.

Unfortunately, some types of natural stone are porous and can absorb liquids.

If they absorb the wrong type of liquid, they may become stained or damaged.

This guide will give you an overview of how natural stone should be sealed and protected.

We’ll also share a few tips for cleaning your natural stone surfaces.

Why does natural stone need to be sealed?

Rocks are made from thousands of mineral grains that are bonded together.

The size of the individual grains will vary based upon how the rock was formed and the minerals that it contains.

Sedimentary rocks like sandstone and limestone have rounded grains with more space between each individual grain.

Igneous and metamorphic rocks will have interlocking grains, with less room between each grain.

That’s because they were formed under much greater heat and pressure.

Rocks with rounded grains are more porous, because liquids can squeeze into the space between each grain.

Unfortunately, this means that these types of stones can stain more easily.

The permeability of each type of rock also affects how likely it is to stain.

The permeability is how interconnected the pores and capillary structures of a rock are.

The more permeable a rock is, the deeper fluid can travel into it.

The rocks most likely to stain are sedimentary (limestone, sandstone), with metamorphic (marble and slate) being less likely.

Igneous rocks (granite) are the least likely to stain because they are formed under such high pressure and have limited porosity/permeability.

The substances most likely to stain natural stone surfaces are oils, red wine, and chemical cleaners.

Sealing natural stone surfaces

Natural stone can be sealed to reduce the rate that fluids can penetrate the surface.

There are two main techniques used to seal natural stone:

Polishing

Natural stone can have its surface polished to even out the surface and fill any holes.

This can slow the rate that fluids penetrate the stone.

It is usually best to have a professional polish any large natural stone surfaces.

Sealants

There are many different sealants available.

Topical sealers will create a protective layer on the surface of the stone, which prevents fluids from penetrating deeper into the stone.

A topical sealant may change how the surface of the stone feels and changes its appearance.

They are available with a matte or gloss finish.

Penetrating sealers are pushed deeper into the stone, where they harden and create a waterproof or water-resistant barrier.

These sealants won’t change the surface texture of the stone.

Sealants are usually chemicals or resins with hydrophobic (water-repelling) and oleophobic (oil-repelling) properties.

Most sealants will allow vapours to travel into and out of the stone.

Many natural stone products are pre-sealed.

They are dipped into a pre-seal treatment so all 6 sides are coated.

This technique is particularly use for natural stone tiles and worktops.

Maintaining natural stone surfaces

Once you have sealed your natural stone, you can clean it with warm water combined with a few drops of a neutral cleaning solution and stone soap.

There are also some commercial products which are designed to safely clean specific types of stone surfaces.

Do NOT use untested chemical cleaners and do not use products that are very acidic or alkaline.

This includes vinegar and citrus-based cleaners.

They can permanently mark or discolour your natural stone surfaces.

You will need to re-seal your natural stone surfaces periodically.

How frequently you do it will vary based on the type of natural stone you are using, where it is located in your home, and how often you use it.

A limestone worktop in a busy kitchen will require much more attention than a granite worktop in a guest bathroom.

The key to ensuring your natural stone surfaces are not marked by liquids is to keep them clean and remove spills immediately — especially if you have a natural stone surface that is porous and permeable.

We hope you enjoyed reading How to Seal and Protect Natural Stone.

If you have any questions about sealing and protecting your natural stone surfaces, contact Carrara Marble on 020 8838 4604.