All look alike products do not perform the same even though they are making similar claims. How do you know which one to believe?
Sodium Silicates: How do you know which one to believe definitely applies to sodium silicates. Sodium silicate formulas have been around since the 1950’s and were initially used as concrete floor hardeners. Today because of their economical nature many concrete manufacturers and distributors claim sodium silicates to be effective waterproofers. Sodium silicate solutions have a place as a concrete treatment; however, their role should only be limited as concrete surface hardeners. Sodium silicate solutions perform very poorly and ineffective as waterproofing sealers since they have a limited depth of penetration and they are unable to stop or reduce hydrostatic pressure. If you want to densify your concrete a sodium silicate hardener is an excellent option; however, leave the waterproofing to one of the other methods below.
Siliconates: Siliconates are as a highly alkaline aqueous solutions that are used for water-repellent impregnation. After the water has evaporated from the sealer, siliconate reacts with atmospheric carbon dioxide to form a water-repellent surface barrier. Siliconates are good water repellent options with an excellent water bead effect.
Silicate/Siliconates: An effective waterproofing method because of the densification properties of the silicate and the hydrophobic properties of the siliconate. Typically silicates are used to harden and siliconates are used to protect from water and by combining the two a dual action product is created. The silicate component reacts with the concrete by introducing additional silicate that reacts with excess calcium hydroxide to form more CSH. This results in a denser, harder concrete surface. The siliconate applied to the concrete undergoes a two part process in which it first reacts with carbon dioxide in the air to form an active silicone resin. The silicone resin then reacts with calcium hydroxide to form a liquid repellent resin on the concrete surface and within the available capillary pores. Siliconates are sealers, not densifiers and are best used when blended with silicate to provide both densifying and sealing properties. The seal elicited is microscopic and there is no film build up on the surface which means it cannot wear off over time. An excellent option for waterproofing basements and driveways.
Silanes: The main deterioration mechanism for concrete is corrosion and scaling due to deicing products. The most effective solution to protect water and salts from damaging concrete is to use a silane based sealer. Because silanes do not change the skid or slip resistance of concrete they are ideal for driving surfaces (aka driveways, bridges, roadways). Silanes penetrate deep because of their extremely small molecular size and they chemically bond with silica to form a permanent attachment of the water repellent molecule. This creates a deep hydrophobic layer that prevents water and waterborne contaminants from entering the substrate and causing premature deterioration. Silanes leave the surface with a completely invisible finish and elicit a water sheeting effect.
Siloxanes: Siloxanes have a larger size polymer and penetration is not as deep as other sealers. Unlike silanes, which require a high pH to catalyze, siloxanes are not dependent on substrate pH. Because of this, siloxanes are ideal for treating brick, stucco, and stone. Siloxanes are not commonly used as a stand alone products but to maximize their potential they are typically blended with silanes. Used as a stand alone product siloxanes may slightly darken the treated surface while also creating a water beading effect.
Silane/Siloxanes: Silanes and siloxanes are both derived from the silicone family. Despite being very closely related, they have significant performance differences. Because silanes are made up of smaller molecules than siloxanes, they typically will obtain deeper penetration than siloxanes. As a result, silanes perform well under abrasion and weathering conditions. A consequence, however, of this small molecular size is that silanes are relatively volatile. Therefore, the solids content of a silane product should be high enough to compensate for the loss of reactive material through evaporation during application and cure. Siloxanes, because they are less volatile, generally offer good water repellent performance at lower costs. However, for concrete surfaces subjected to abrasive wear, treatment with a silane sealer will provide longer lasting protection. In regard to surface texture and color, treatment with silane sealers typically cannot be detected visually. Siloxane products may slightly darken the treated surface. By using a combination of silanes and siloxanes the benefits of each compensate for the weaknesses of each making for the perfect DIY water repellent sealer. Silane/Siloxane blends are commonly used on driveways, sidewalks and leave the surface with a natural finish.
Elastomeric Coatings: Elastomeric coatings are rubberized emulsions which cure to provide a heavy duty rubber-like membrane for use in waterproofing or damp proofing concrete or masonry surfaces above and below grade. The term elastomeric simply means that the material is flexible. Elastomeric coatings are durable and essentially derivatives of urethanes and polyurethanes formulated into a liquid which can be applied to form a monolithic waterproofing membrane. While elastomeric coatings are impermeable to water, chemical vapors and sub-terrain gases they are at high risk of delamination with a short lifespan. They also alter and change the color, texture and surface appearance of concrete.
Crystalline Waterproofers: Crystalline waterproofing is an effective waterproofing method because it fills capillaries to prevent the penetration of water and other liquids from any direction. By way of diffusion, the reactive chemicals in crystalline waterproofers use water as a migrating medium to enter and travel down the capillaries of the concrete. A chemical reaction between the crystalline waterproofers occurs between moisture and the by-products of cement hydration, forming a new non-soluble crystalline structure. This integral structure fills the capillary tracts rendering the concrete waterproof.
Basements: Look for an invisible waterproofing silicate/siliconate blend that will densify and waterproof. If your basement is built of cinderblocks or concrete blocks look for a silane/siloxane blend. Since silane/siloxanes have a larger molecular size they are able to mask and bridge the especially porous blocks from potentially damaging water.
Driveways: Look for a penetrating silane/siloxane sealer that will protect driveways from salt degradation, mold, mildew and unsightly efflorescence. One of the best effects of a silane/siloxane sealer is the ability to see it working right before your eyes with its water beading effect. Look for a silane/siloxane of 20-40% solids.
Patios: Depending on the desired finish of either a high gloss shine or a matte finish choose either a solvent based acrylic or water based acrylic. Be careful when choosing a solvent based sealer if it meets VOC regulations in your state. Water based acrylics, if industrial grade formulations, are excellent decorative concrete enhancers.
Garages: If you are looking for chemical resistance, abrasion resistance and resistance from oil, gas, acids and other chemicals use an industrial coating, either an epoxy, urethane, polyaspartic or a conjunction of an epoxy and urethane. These coatings are also resistant to hot tire pick up and heavy equipment and machinery.
Warehouse Sealers: The best sealers for warehouses are concrete densifiers or industrial strength coatings. Concrete densifiers are usually sodium silicate sealers or lithium silicate sealers that will harden and dustproof concrete. They are especially used when polishing a concrete warehouse. Industrial strength coatings like urethanes and polyaspartics are used when chemical or abrasion resistance is needed. The concrete floor must be grinded before applying one of these coatings in order to maximize adhesion.
Basement Waterproofers: Silicate/Siliconate blends are necessary for waterproofing concrete basements. With the densifying characterisitcs of the silicate and the hydrophobic waterproofing barrier of the siliconate water does not stand a chance. However if the basement is composed of concrete blocks or cinderblocks a silane/siloxane sealer must be used. Look for one that is at least 20%-40% solids. Do not use a straight silicate sealer for waterproofing since it is a densifier not a waterproofer.
Driveway Sealers: Silane/Siloxanes, or industrial water based acrylics are fantastic options that will protect a driveway from mold, mildew, efflorescence and salt degradation.
Patio Sealers: Water based or solvent based acrylic sealers that will add a matte finish or high gloss shine depending on the desired finish. If the area is prone to slipperiness use a water based sealer. Acrylics are excellent choices for brick pavers as well.
Garage Coatings: Depending if a natural concrete finish is desired or a decorative coating is desired use either a silicate/siliconate sealer or an epoxy/urethane system. The silicate/siliconate will help to prevent the passage of vehicle fluids while the epoxy/urethane system will be extremely chemically and abrasion resistant. Also with an epoxy/urethane system, paint chips or decorative sand can be added for an aesthetically pleasing appearance.
Basement Sealers: For concrete blocks or cinderblock walls use a silane/siloxane sealer. For poured foundations or concrete slabs use a silicate/siliconate sealer to densify and waterproof.
Driveway Sealers: Use a silane/siloxane sealer if you live in a colder climate with a lot of snow and ice. For a warmer climate you can use a water based acrylic formulation.
Patio Sealers: Use a decorative acrylic sealer either solvent based or water based. Solvent based sealers will not be VOC compliant in all 50 states but they will leave a high gloss shine. Water based sealers leave a matte finish but have no harsh, solvent odors.
Warehouse Sealers: If the concrete will be polished use a concrete densifier; either a sodium silicate or a lithium silicate. If you are looking for chemical or abrasion resistance use an aliphatic urethane.
Garage Sealers/Shop Floors: If you are looking for a natural garage floor use a siliate/siliconate blend. If you are looking for a decorative finish or for added chemical/abrasion resistance use an epoxy coating followed by an aliphatic urethane topcoat.
Countertop Sealers: Use a concentrated penetrating acrylic sealer that you work into the concrete. Use in conjunction with a concrete wax for added protection and shine.
When it comes to most things in life you are looking for long lasting, durable solutions. When it comes to concrete sealers and concrete coatings you are looking for the same. Most sealers on the market need to be reapplied frequently. Acrylic sealers are known for this, needing to be reapplied on an almost yearly basis. Coatings like epoxies and urethanes tend to last longer up to an average of ten years. There is more of an investment put out up front but with the chemical resistance and abrasion resistance properties gained with an epoxy/urethane system it is well worth the expenditure.
After perusing the internet, I am sure you have seen some companies offering lifetime warranties on their products. The products they are most likely warrantying are penetrating concrete densifiers. The reason they can offer these types of warranties is because silicate densifiers penetrate into the concrete causing a chemical reaction to occur below the surface of the concrete. Concrete is permanently strengthened and hardened. However, if a company is offering a lifetime warranty on a waterproofing sealer I would be skeptical. Silane/Siloxane sealers typically last 5 years before needing to be reapplied. As soon as the water beading effect starts to fade you know it is time to apply another coat.
Our Take: All in all concrete sealers are durable solutions to seal, densify, harden, waterproof and coat concrete. Some sealers last longer than others and some companies offer excellent warranties to back their products so you cannot lose even if they don’t perform as advertised.