The number one arch enemy of concrete is water. Not only can water create harmful health risks with the growth of mold and mildew and create numerous problems for homeowner’s foundations but it can also be a carrier for salts and chlorides that can damage reinforcing steel in concrete leading to spalling and cracking. In order to prevent water from damaging concrete basements, driveways and other surfaces a waterproofing concrete sealer should be used. A lot of sealers on the market are elastomeric, latex based or acrylic based and while they can temporarily help to reduce water is only a matter of time before they delaminate. Since they are unable to penetrate but instead coat the surface it is more like putting a bandaid on the problem instead of sealing from within.
By using a penetrating, impregnating sealer that densifies and hardens concrete and also provides a hydrophobic surface barrier you can ensure a fully waterproofed substrate. One of our favorite concrete waterproofers is Lithi-Tek 9500. This sealer is an invisible, penetrating concrete sealer that will not only densify concrete, but it will waterproof and help to prevent deleterious organic growth. The chemically reactive and active ingredients seal the pores within the substrate adequately blocking surface moisture while still maintaining the concretes ability to breathe. It will not significantly modify substrate appearance or traction and will only wear away if the concrete surface itself wears away. New or existing concrete can be treated and performance can be improved in as little as two applications. The concentrated nature of the sealer allows for 1000 sq. ft. of coverage per coat from 1 gallon (two coats are recommended so each gallon will yield 500 square feet worth of coverage) and it is now readily available at HomeDepot.com and Lowes.com. This sealer only costs about $0.10 per square foot per application; considering the cost to replace concrete is about $7.00 per square foot, sealing concrete with the 9500 is a worthwhile investment.
The Siloxa-Tek 8505 is a revolutionary product that is able to repel salts (including deicing salts), oils and stains from household products, automobiles, bbq grills, leaves and more. Of a silane/siloxane chemistry with an added proprietary component this product is unrivaled when it comes to sealing driveways, warehouses and patios to name a few. This product leaves a completely clear, natural finish so once you apply it, you wont even know it is there except when water, and fluids are spilled on the surface and they bead right up like a newly waxed car.
A lot of manufacturers claim their products will “limit the penetration of stains”; however, this is different and must not be confused with a sealer that is formulated to actually repel stains and oil like the Siloxa-Tek 8505. The manufacturer would not give away the proprietary ingredient but we tested it in comparison to the products that claim to limit the penetration of stains and there is no comparison. The proprietary ingredient in the Siloxa-Tek 8505 is extremely effective and performs as described on the technical data sheets and the manufacturer is actually able to provide testing data on request.
This product is available in two variations, a water based version for residential applications and small commercial applications or a solvent based version for larger commercial applications. The water based version is available in a ready to use formulation or a ultra concentrated version (both are readily available for purchase through Lowes.com and if you prefer, formally known as the Siloxa-Tek 8500 OR, The Home Depot.com carries the ready to use version). The ready to use product will cover 125 sq. ft. per container for both applications and the ultra concentrated product will cover 625 sq. ft. per container for both applications. If you are looking for industrial or commercial use of this product, it is also available in a solvent based version is called Siloxa-Tek 8510 and is available through the manufacturer in 1 gallon, 5 gallon bucket or drum quantities.
When it comes to application it could not be easier to apply. A garden variety sprayer, or nap paint roller is recommended. Two coats are highly recommended and upon talking to the manufacturer they essentially require it. The coats are applied wet-on-wet. What wet-on-wet means is that the second coat is applied before the first coat has dried. Because the product is so hydrophobic if you try to apply the second coat after the first coat has dried the first coat will try to repel the second coat. However, if you apply the second coat while the first coat is still wet you are able to get the product to penetrate as deep as possible and ensure the longest lasting performance. A good rule of thumb is to apply a first coat to a 500 square foot section and go back and apply the second coat to the same 500 square foot section and then move on to the next section and apply a first coat, then second coat. (You can walk on the first coat to apply the second coat, since it is a natural finish product it will not leave footprints).
What we love most about this product is that it does not need to be reapplied every year or even every few years but the product has a lifespan of up to 10 years before needing to apply another 2 coats. We recently came across this distributor, Concrete Sealer Solutions, which has the ultra concentrated version on sale for $15 less than Lowes! Since the product is concentrated, the price breaks down to about $50 per gallon, quite a bargain when it comes to protecting a concrete driveway from spalling, pitting, cracking, deicing salts, oil, auto fluids and leaf staining.
When it comes to answering the question of what the best concrete sealer is, its hard to pin point one type of sealer for all applications. There are a lot of factors that go into choosing a sealer including application (driveway, patio, etc.), substrate (concrete, brick, masonry) and functionality (salt repellent, waterpoofer, oil repellent, decorative).
Below is a quick reference guide that highlights common applications, substrates and functionalities:
Concrete Driveway: If you are looking for deicing salt protection use a silane/siloxane blended sealer. If you are looking for oil and staining protection use a silane/siloxane with a stain protector like the Siloxa-Tek 8505.
Concrete Basement: If you have active moisture or water issues it is best to use a two step application by first using a densifying primer of a lithium silicate carrier, followed by a penetrating silane/siloxane product. If you do not have active moisture issues and are looking to proactively seal, use this fantastic all-in-one product found at homedepot.com
Concrete Blocks/Cinderblocks: Because of the porous nature of the concrete cinderblocks it is best to apply three to four coats of a penetrating silane/siloxane sealer.
Stone/Stucco/Slate/Bricks: Stone, stucco, slate and bricks are best protected using a penetrating, natural finish silane/siloxane sealer that will not encapsulate the substrate so it is still able to breathe.
Patio/Pavers/Pool Deck: When sealing a patio, pavers or pool deck it is best to first figure out the desired finish if you are looking for a natural/clear finish, low sheen or wet look/gloss. If you are sealing a salt water pool a silane/siloxane blend is going to be the best option to keep the pool deck from spalling and pitting. Keep in mind that the natural finish products are penetrating and give the longest lasting, best protection. Whereas low sheen and gloss finishes typically need to be reapplied on a more frequent basis.
Natural/Clear Finish: Penetrating silane/siloxane sealer
Low Sheen: Water based acrylic
Wet Look/Gloss: Solvent based acrylic
Waterproofing/Salt Protection: A penetrating silane/siloxane like this one that gets great reviews from HomeDepot.com
Oil/Staining Protection: Lowes.com offers this product in a concentrate so you get to control the mixing and application. It’s great to protect driveways from oil stains and leaf staining and backyard patios from BBQ grill and food stains.
Silane/Siloxane sealers are commonly used as water repellents and waterproofers especially on extremely porous cement based substrates like cinderblocks, stucco, brick and concrete. Excellent sealers for protection from freeze-thaw damage and salt degradation and commonly used on municipality jobs, highways and bridges.
Most Important Features When Purchasing a Silane/Siloxane Sealer:
- Non-yellowing and water based
- Resistance to mold, mildew, salt degradation, freeze-thaw damage
- Resistance to ASR, chloride penetration and water
Most Popular Silane/Siloxane Sealer Brand Reviews:
Siloxa-Tek 8500: Silane/siloxane designed for extremely porous concrete and masonry substrates. We have found this sealer to be extremely effective against salt degradation, spalling, cracking, freeze-thaw damage and water. We love that it is water based but performance is comparable and outperforms a solvent based silane/siloxane. 100% breathable with a 10 year warranty.
Eagle Natural Seal: Low percentage solids silane/siloxane extremely economically priced. Wide variety of applications and covers a substantial amount of square footage per gallon. No warranty on the product.
Okon S-20: High percentage solids, also available in a 40% solids version. Good protection against water and we love the ease of application with a low pressure sprayer. Low square footage per gallon.
SureKlean Weather Seal: Ready to use silane/siloxane that is also water based designed to repel water from most masonry and stucco surfaces. Will help to reduce cracking, spalling and staining. Adequate performance over time, need to reapply every few years.
Blok-Lok: We don’t like that is was not specifically designed for concrete, multi-surface sealer with a five-year warranty. Low square footage per gallon, we do like that it can be applied within 48 hours of concrete being poured since this is not a normal benefit of silane/siloxanes.
One of the most sought after concrete sealing products is a waterproofing sealer that is also able to repel deicing salts. Deicing salts and calcium chlorides are some of the most corrosive elements that concrete can be exposed to. They result in spalling, pitting, cracking and cause the concrete to erode all the way down to the rebar if left untreated. Because concrete has the appearance of being strong and indestructible, sealing it is not something that comes to mind – that is until you have active salt damage. Even if you do not salt your driveway, state and town roads are treated, you drive your car up the driveway into your garage and the salt drips off. Over time the concrete becomes damaged.
It is hard to fix existing salt damage with a sealer; however, it is entirely preventable if a penetrating water repellent with saltguard sealer is used. We review the Ghostshield 8500 product quite frequently on this site because it is one of the products we have used that has had the best, longest lasting results. Backed by a 100 year warranty, if reapplied every 10 years, concrete will remain looking new with out any spalls, pits or cracks. This is extremely important because the cost of replacing an existing concrete pad or driveway is about 14x the cost of the actual sealer itself!
Our Take: The 8500 product is a great option if you have a lot of square footage. The product is available in an ultra concentrated gallon; you take the 1 gallon you purchase and mix it with 4 additional gallons of water. When mixed you are left with a 5 gallon bucket which covers up to 625 sq. ft. (the 625 sq. ft. is for both recommended coats or 1250 sq. ft. for 1 coat). The ready to use version that does not require mixing and can be special ordered through Home Depot and Lowes. Whereas the ultra concentrated version can be ordered through Lowes and Concrete Sealer Solutions (Concrete Sealer Solutions sells the 8500 for $15 off Lowes pricing).