Should Stained Concrete be Sealed? (5 Main Reasons)


Due to the composition in its materials concrete is a slightly porous material, water and contaminants can easily penetrate its surface and gradually attack the material from the inside.

Therefore, sealing on stained concrete floors is essential for several reasons, sealing will protect the color of the stain from stains caused by moisture, corrosion, or external factors, at the same time, sealing on a stained concrete floor enhances the color of the stain giving it the final finishing touch.

While damage to concrete is usually not visible for a long time, it is important to seal concrete floors to make them more resistant to moisture, UV radiation, chemicals, mechanical stress, and corrosion.

Concrete stains can be divided into three types, depending on their components, for each of these stains will need sealing after application for various reasons, the types of concrete stain are:

  • Acrylic-based
  • Polymer-based
  • Acidic-based

Here are several main reasons why you should seal stained concrete surfaces.

1-Highlights the color of the applied stain

The primary reason for sealing a stained concrete surface, aside from protection, is that sealing brings out the stain color, giving it a totally different appearance than a stained concrete surface without sealing.

Stained concrete surfaces without sealer applied usually look dull, unfinished, faded, and non-glossy, although, for people who do not like gloss, there is also a matte or semi-matte concrete sealer available.

In concrete acid stain applications, for example, sealing is so essential that the only way the beauty of the stain can be appreciated is by applying the sealer, the difference in appearance is heaven to earth in a stained floor without sealer to one with sealer applied.

2-Prevents stain deterioration due to humidity stains

As mentioned at the beginning of this topic, concrete is a material with certain porosity, the main reason for using a sealer on concrete is to correct this weakness as much as possible.

The problem with the porosity of concrete is that it makes it a vulnerable material to environmental factors such as moisture, a concrete surface without a sealer or moisture barrier will create constant staining that will create unpleasant color inconsistencies in the concrete.

3-Protection of the color of the stain to the solar UV radiation

There are some concrete stains that are polymer-based, these stains tend to suffer from fading and peeling when exposed to direct sunlight and receive many hours of solar radiation.

For the protection of these stains, the use of a sealer is essential, especially when used in exterior spaces.

4-Avoid corrosion and chemical stains

The only color you want to highlight on a stained concrete surface is the color of the stain applied, a stain caused by corrosion or some other type of chemical reaction of the concrete with other substances would completely damage the aesthetics of the stain.

5- Avoiding concrete surface degradation

The calcium present in the concrete surface may be dissolved by a chemical process called leaching, causing degradation of the concrete by the destruction of other of its components.

This degradation can occur in pure water, free of salts, soft water with few impurities, industrial condensation water, and even rainwater.

When does concrete sealing make sense?

Concrete seals and impregnations also protect against contamination and facilitate the cleaning of the concrete surface. This can prevent stains from certain cleaning agents, greases, and oils from discoloring the concrete or from being impossible to remove.

There are many areas of application where concrete sealing makes sense. Industrial concrete floors, garage, and workshop floors are made resistant to gasoline, acids, alkalis and mechanical stress by sealing.

Concrete sealing can also be useful for basement floors, living rooms and recreation rooms where cement or concrete floors are used extensively.

Acid-stained floors must be sealed no matter where they are applied, as the sealing of this type of stain ensures proper color matching.

A concrete seal in the garage also prevents the plasticizers contained in car and bicycle tires from damaging the concrete floor over time. Incidentally, this risk also exists the other way around, because a garage floor made of concrete can attack rubber tires due to its chemical nature and make them brittle.

When does it make sense to use concrete sealer inside a home?

Concrete floors can look very elegant in living spaces. Typically, indoor surfaces of concrete are usually protected or coated anyway to protect them from stains, to make them better for cleaning and easy maintenance properties, or to enhance the look and feel of the floor as a whole.

Surface sealing or protection also prevents any fine dust created by the natural wear and tear of concrete from entering the ambient air of the room.

For family and indoor use areas, we recommend a concrete sealer that is as non-polluting as possible, easy to care for, has a nice appearance and has a good feel.

In case an acrylic stain is chosen it can be a good concrete color or a clear coating, there are solvent-free and water-based products available, categorized as “environmentally friendly”.

Seal concrete floors with epoxy resin, synthetic resin dispersion or liquid plastic

If you look at concrete sealing products in hardware stores, you will find that most of them are based on synthetic resin dispersions, often reinforced with polyurethane (PU), or epoxy resin.

The two-component concrete sealants based on the epoxy resin are particularly suitable for sealing garage floors because they reliably protect against moisture penetration and keep dirt, oil, and petrol away from the concrete floor.

In addition, an epoxy resin seal prevents unwanted chemical reactions from taking place between the concrete and the vehicle tires.

Seals based on synthetic resin dispersions or PU-reinforced dispersion resin cannot do this very well because they are less resistant and tend to crack and flake off.

Both epoxy resin concrete sealants and those made from PU-reinforced synthetic resin dispersions contain volatile solvents and other harmful and dangerous ingredients.

Therefore, always ensure good ventilation during processing and wear protective clothing and respiratory protection in accordance with the manufacturer’s instructions.

Prior to the application of the concrete sealer

Thorough preparation of the substrate is also very important, i.e. thorough cleaning (e.g. with a high-pressure cleaner) and removal of all old grease and oil stains, if necessary with a very effective aggressive solvent such as nitro thinner.

If the concrete floor already has cracks, they must be cleaned and prepared with special care. If you forget a little grease that is right at the bottom of the crack, there is a risk that the concrete seal will soon come off again at this point.

Once it starts to peel off, the process usually soon continues, and all the work has been in vain. Scrubbing a concrete floor with Thinner is a really uncomfortable, arduous, and also dangerous job.

Be sure to wear good skin, eye and respiratory protection, plenty of fresh air, and enough breaks to protect yourself from poisoning.

how long to wait to seal the concrete after staining?

The application of the sealer to the stained concrete can be applied approximately 1 to 2 hours after you have washed the surface after the application of the stain.

After applying the stain to the floor, ideally, it should be washed with water to remove any solid residue or dust before applying the sealer, the sealer can be applied immediately after the floor is completely dry, depending on the environment and ventilation a concrete surface can be dry between 1 and 2 hours maximum.

I recommend that you help with the drying of the surface avoiding leaving accumulated puddles of water.

On other websites I have read that it is recommended to leave 24 hours before sealing the surface, this seems impractical to me because I always like to clean the surface with water before applying the sealer, what I do is clean the surface well with water, give me a break of one or two hours to have lunch and then I come back to apply the sealer, everything is perfect.

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