This type of concrete sealer penetrates the concrete or masonry surface by entering via the capillaries and voids and soaks under the surface and reacts with it chemically. It creates a new chemical solid that forms a breathable barrier over or below the concrete surface, which gets sealed but does not coat the surface top and this barrier prevents the dampness from penetrating the surface.
Penetrating sealers generally do not change the texture or appearance of the surface and provide a natural look. They offer a distinctive, clear matte finish and after the sealer dries, you will not even notice any difference. Penetrating sealers are commonly used on outdoor surfaces to safeguard against staining and harsh weather conditions and work well to protect pool surroundings, patios, decks, and other outdoor entertaining areas as well as interior concrete surfaces. Most penetrating sealers are breathable, permeable, and let the moisture escape.
Since most of the penetrating concrete sealers adhere to the concrete surface permanently, they last as long as the surface lasts or until the surface’s top to the concrete sealer’s depth lasts. You can apply penetrating concrete sealers to either dry surfaces or wet ones; however, you must match the porosity of the surface properly so that the concrete sealant penetrates the surface and reacts effectively. Usually, penetrating concrete sealers last for around 5 years or more. If you need to apply a second coating, you can apply it without removing the first coat.
Finally, penetrating concrete sealers come in two kinds: water- and solvent-based sealers. The solvent-based varieties have higher VOC (volatile organic compounds) and also have more sheen compared to water-based sealers. There are four types of penetrating concrete sealers: silane sealers, siloxane sealers, silicate sealers, and siliconate sealers. Let us take a quick look at each one of them:
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Silane and siloxane concrete sealers work differently compared to the other penetrating sealers. The molecules penetrate the concrete; however, they do not densify the concrete by reacting with it chemically. Instead, silane and siloxane molecules work in the concrete surface and create a hydrophobic barrier, which repels water and moisture.
The silane molecules complement the barrier and reinforce it, making it stronger; at the same time, the siloxane molecules remain on the concrete’s surface and provide strength. Both these sealers are ideal for concrete surfaces like concrete block, cinder blocks, bricks, and materials that are more porous or where you cannot use silicate concrete sealers.
Silane sealers are perfect for high PSI or dense concrete surfaces since they comprise of very small molecules, which can penetrate smaller pores and these can penetrate much deeper as compared to a concrete sealer with larger molecules. Silane concrete sealers can repel both water and oil very well.
However, the drawback of silane sealers is that they cause the darkening of the concrete surface and they bond with any oils present in the concrete and cause staining. So, it is very important that the concrete surface must be thoroughly cleaned before using a silane sealer.
These are essentially derivatives of silane and have larger-sized molecules compared to silanes. And so, their penetration is shallower. However, siloxane concrete sealers have great topical advantages and are suitable for porous materials because of their large-sized molecules.
A silicate sealer is a penetrating sealer comprising of small particles of silicate that are suspended in a lithium or sodium carrier, which carries the silicate particles through the pores of the concrete. Once the silicate particles are inside the concrete, they go through the network of pores and hairline cracks and react chemically with the minerals present in the concrete to form CSH (calcium silicate hydrate), which makes the concrete surface stronger and also helps to prevent the entry and passage of salts, water, chemicals, etc. through the concrete.
When applied to the concrete, the silicate concrete sealer dries and forms a chemical bond that is non-soluble and permanent. Silicate sealers have a polished appearance and another advantage is that they provide radon protection. Silicate concrete sealers are suitable for machine-troweled or very smooth concrete surfaces like garages and basements.
Siliconate sealers contain larger molecules compared to silicates but they can penetrate deep into the concrete and chemically react with it. Siliconate concrete sealers help to strengthen the concrete and protect it effectively from water intrusion and freeze-thaw cycles. This concrete sealer also protects the concrete from wear and tear, staining, salts, de-icing fluids, and mold.
Siliconate concrete sealers are multipurpose, which means that you can apply it to concrete any time at all. You can apply these sealers to new concrete, which is still in the process of curing, or to old concrete, which needs resealing. Siliconate sealers are very easy to apply, they do not alter the appearance and texture of the concrete and are very effective.