Review of Sealants or Sealers for Concrete and Masonry

What is the difference between "sealants" and "sealers"? Although the terms are commonly interchanged, sealants typically leave an elastic layer on the surface like rubberized coatings or caulks. Sealers are either film-forming like acrylics, urethanes, and epoxies, or they are penetrating, sealing the substrate internally. We specialize in the state-of-the-art penetrating sealers because they provide the tightest and practically permanent seal.

Wax sealers
Pros: The most basic sealants. Easy to use. Provide a low to high sheen. Often used by contractors as a curing agent for green concrete and to keep surfaces clean during construction. Inexpensive. Meant as temporary only. Leave a film, which has to be removed before painting or installing tiles. Sold to public as a driveway sealer.
Cons: Relatively poor sealing properties. Stain easily. Short life. Must be reapplied frequently. Susceptible to UV-rays, heat, and corrosive materials. They usually disintegrate within a few months.

Waterproofing coatings for foundations
Pros: Tar or asphalt coatings are the cheapest but are only effective for damp proofing, not waterproofing. Polymerized (rubberized) waterproofing coatings last much longer and are available in spray-on version or in sheets for application like wallpaper.
Cons: Tar and asphalt are brittle and will flake off after time. As the foundation settles and the concrete continuously moves, they crack and degrade in several years. All coatings, including the polymerized waterproofing coatings, get attacked by lime in the concrete, which causes them to separate. (Solution: Neutralize the alkalis and seal the concrete first with RadonSeal.)

Latex-based waterproofing paints
Pros: Can be applied to interior or exterior vertical surfaces. Water-based. Easy and safe application. Inexpensive and widely available in home improvement stores.
Cons: Crack and peel like all paints where needed the most because water pressure and efflorescence lift the surface film. Moreover, lime and alkalis from the concrete attack all paints or coatings by "saponification.” Soft and susceptible to wear and abrasion. Not suitable for floors. Re-painting means high maintenance costs. The old paint must be removed first because two layers would trap more vapor and speed up the peeling.

Acrylic sealers
Pros: Form a shiny film and enhance the appearance of colored and decorative concrete. Good for exterior applications because of their UV resistance. Available as water-based or solvent-based. Solvent-based can provide more gloss and will hold up better on exterior surfaces. Water-based acrylics are ideal for indoors because they are much less toxic with very low odor.
Cons: Acrylic sealers are relatively soft and need to be reapplied frequently due to surface wear. Solvent-based acrylics pose health and fire hazards. Water-based acrylics are safer but are less durable. Acrylics are susceptible to black heels marks and “hot tire” pick-up.

Urethane coatings
Pros: Much stronger than acrylics and resistant to traffic. Used often indoors due to their high gloss. Available as water-based or solvent-based. Solvent-based can provide the “wet look” to surfaces. Water-based urethanes are better for indoors due to their low odor.
Cons: Solvent-based urethanes pose health and fire hazards. Urethane coatings are not permeable to water vapor and if installed on a foundation slab, will trap moisture, activate efflorescence, bubble and crack.

Epoxy coatings
Pros:  Very strong and durable. Bond well with concrete surfaces and form a transparent, shiny film. Allow for easy cleanup of spills.
Cons: Not permeable to water vapor. Trap moisture and will not let the substrate “breathe.” This causes efflorescence, bubbling, and cracking. Require significant surface preparation before application. Expensive. A secondary “sacrificial” coating is recommended to protect the epoxy coat against scratching.

Crystalline sealers
Pros: Penetrate deep into concrete and deposit tiny silicate crystals into the pores, which then expand on contact with water and thus seal the concrete against water from both positive and negative sides.
Cons: In the absence of water, they do not seal against water vapor or gases like radon.

Cementitious slurry sealers
Pros: Troweled on the surface to form a cementitious coating. Well-proven for stopping water seepage through leaking concrete walls. Some contain silicate crystals that penetrate into the surface of concrete.
Cons: The "cold joint" of the coating with the old concrete is vulnerable. Efflorescence and water pressure cause its separation and bubbling. Cannot reduce water vapor or radon gas. As the waterproofing crystals get pushed out over time, it loses its waterproofing property. (Then, it can be re-sealed with RadonSeal.)

Silane sealers
Pros: Can be used on a variety of surfaces (concrete, bricks, and masonry). Form a film on the surface and penetrate a little into the surface. Repel rainwater and bead. Let the substrate “breathe.” Modern silanes can achieve deeper penetration and do not yellow.
Cons: May become slippery when wet. Most use chemical solvents. Will often darken the substrate. Many will yellow. Not suitable for negative side water pressure. Not paintable. Disintegrate due to UV-rays or traffic. Regular re-application required.

Siloxane sealers
Pros: Form a water-repellent layer inside and below the surface, which sheds and beads water. Like filling the pores with silicone caulk. Usually penetrate 1/8” to 1/4”. Let the substrate “breathe.” For concrete, bricks, and masonry.
Cons: May become slippery when wet. Not paintable. Not suitable for negative side water pressure. Susceptible to UV-rays. Regular re-application needed.

Polyester sealers
Pros: Penetrate deep into the pores in concrete, bricks, or masonry, cure and harden as a plastic. Like filling the pores with epoxy. Deep-seal permanently and strengthen the substrate. Waterproof against both positive and negative side water pressure. Let the substrate “breathe.” Water-based. Paintable. No re-application needed.
Cons: Reduce but not stop vapor, gases, and efflorescence.

Silicate sealers
Penetrate the deepest and seal the tightest. React with lime and alkalis in concrete to fill the pores. Like filling the pores with cement. Strengthen the concrete and harden the surface. Seal against both positive and negative side water pressure. Let the substrate “breathe.” Stop efflorescence. Permanent. No re-application needed.
Cons: Only for concrete and cementitious materials.

Our Line-Up of State-of-the-Art Penetrating Sealers

These premium waterborne concrete sealers have higher concentrations of the key compounds and unique characteristics that make them top-performers in their categories:

RadonSeal Deep-Penetrating Concrete Sealer is a silicate-based reactive sealer. Compared to other silicate sealers, RadonSeal is heavier, penetrates deeper, and seals tighter – not only against water but also against vapor and even radon gas. Still lets the substrate "breathe" and dry out. More about RadonSeal Concrete Sealer

Unlike other siloxane-based sealers, Ion-Bond Armor Subsurface Elastomeric Sealer penetrates much deeper into the substrate and forms a waterproof barrier well below the surface, hidden from UV-rays. It is the only siloxane sealer that is also effective against negative side water pressure. About Ion-Bond Armor Concrete Sealer

LastiSeal Brick & Masonry Sealer is a polyester-based sealer that waterproof a wide range of materials – concrete, blocks, bricks, pavers, and masonry. Its deep penetration makes the seal permanent. LastiSeal Concrete Stain & Sealer waterproofs and beautifies concrete in one step with a choice of colors and safety superior to acid staining. About LastiSeal Brick & Masonry Sealer or LastiSeal Concrete Stain

Taking the best features of siloxane and silane sealers, our DryWay Water-Repellent Sealer penetrates into the substrate and forms an internal water-repellent barrier. A long-lasting protection for driveways, garage floors, pool decks, outdoor concrete, pavers, and masonry. Sheds water for 15 to 20 years. About DryWay Driveway Sealer

For tips how to select the best sealer for your application visit Cutting-Edge Penetrating Sealers for Concrete, Brick, and Masonry