When it comes to sealing a concrete driveway, you want to choose a sealer that will help to protect the driveway against staining and deterioration, mold and mildew growth, and efflorescence. With so many types of penetrating concrete sealers on the market, how do you choose which sealer is best?
Simple. You think about what you want your driveway to look like once sealed, and what your reason for sealing is.
The two main types of penetrating concrete sealers for driveways are densifiers and water repellents. Densifiers are used to increase the strength and density of the concrete, while water repellent sealers reduce the absorption of water and other liquids on the surface. They are both very different sealers and don’t share any of the same benefits.
|Silicate Concrete Sealers||Water Repellent Concrete Sealers|
|Won’t change the look of the concrete||Won’t change the look of the concrete|
|Works entirely below the surface||Works entirely below the surface|
|Apply only once||Recoat every 5-7 years|
|Increase strength of concrete||Repels surface water|
|Reduces dusting and spalling||Reduces staining and deterioration|
|Can only be used on cured concrete||Can be used on cured and uncured concrete|
If you have issues with concrete dusting, or weak and deteriorating concrete, then a concrete densifier is never a bad idea. Densifiers penetrate into the surface of the concrete where they chemically react to form a permanent calcium silicate hydrate (CSH) structure within the pores. Once the structure is formed, which can take up to 90 days, the concrete will have an increased surface strength and density of up to 45%. The two most common types of concrete densifiers are sodium silicate and lithium silicate densifiers. Both spark the same chemical reaction in the concrete, but sodium silicates have a larger molecule making them preferred for porous concrete and lithium silicates have a smaller molecule making them preferred for dense concrete. To learn about the types of concrete densifiers, and research whether or not you need one, refer to our Should I Use a Concrete Densifier article.
Water repellent sealers are the most popular type of concrete driveway sealer. They don’t increase the strength or density of the concrete, but they do cause water and other liquids to bead off the surface. They chemically react below the surface to form a long lasting hydrophobic barrier. They won’t change the look or color of the concrete, but they will reduce surface water absorption by up to 95%. Concrete driveways sealed with water repellent concrete sealer are more resistant to freeze thaw and salt damage, mold and mildew, and efflorescence.
The two main types of water repellent sealers are siliconate water repellents and Silane-Siloxane water repellents. Siliconate water repellent sealers should only be used on white or very light concrete driveways because when applied to medium to dark concrete, can leave a semi-permanent white residue. Silane-Siloxane water repellent sealers can be applied to virtually all types and colors of unsealed concrete without issue. Read our article on the Best Water Repellent Sealers.
Sealers are a great option if you are looking for a cost effective, long lasting driveway sealer, but it is important to understand that a sealer can only do so much.
Sealers work below the surface in the pores, but the surface of the concrete is still exposed. The surface can and will still stain if oil, gas, or other harsh liquids are spilled and left on the surface. While they can slow down the movement through the pores, they can’t STOP staining.
The only way to STOP staining and deterioration is to apply a coating. Coatings leave a protective, visible surface film that takes the abuse so that the concrete doesn’t have to. The most common type of driveway sealer is an acrylic sealer. Read our article on the Best Acrylic Sealers.