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For many years, decorative concrete artisans and contractors have been looking for the best ways to protect their beautiful concrete floors. In this article we will compare four basic methods of floor finishing and protection:
1) Epoxy and urethane;
2) Acrylics;
3) Penetrating Densifiers, Hardeners; and
4) Polished concrete systems with Densifiers.
All of these systems take place in the top 1/16th to 1/8th of an inch on the concrete's surface-the wear zone of your concrete. Densifiers, Hardeners penetrate 1/16" to 3/8" below the concrete surface.
Epoxy and Urethane Thin Film Coatings
There is no better coating than epoxies or urethanes. They are very resistant to stains and chemical attack and they are very shiny and colorful. They function like paint as they cover and hide the concrete surface. They are an excellent choice for creating liquid candy-colored floors and also work well in industrial environments where harsh acids and chemicals are used.
They don't always age well. As time goes by they tend to scuff, scratch, discolor, cut and chip. They are non-breathable and require moisture and pH testing along with a moisture membrane in order to reduce liability and insure the coating won't fail from excess vapor emissions. In general, you can expect to sand and re-apply a thin topcoat every 2 to 10 years. Badly damaged or worn surfaces may require complete stripping and re-application. The lifetime of these systems can be maximized by applying a sacrificial wax(a water-based sealer). The installed cost is between $ 2.00 and $ 6.00 a square foot, depending on the size and detail of the job.
Be sure your cost analysis includes downtime as your coating cures to full strength, and be sure the owner is aware of the life expectancy of this coating system as he or she figures life-cycle costs.
Epoxy and Urethane coatings are great to look at and very durable in the short run.
But the long-term cost can be high, and they are costly and difficult to remove and replace. For residential and retail interiors, garage floors, decorative concrete patios and driveways, etc., the best coating choice is solvent based acrylic sealers and water based sealers and waxes because they are much easier to strip and re-apply and are breathable.
Acrylic Thin Film Coatings
Acrylics sealers are generally used on residential and retail decorative concrete interiors and exteriors that are mainly used for foot traffic.
With Acrylics, the colors on your floor and paving become rich and vibrant, providing a deep wet-look. Want a shiny floor? Seal it with an acrylic. Want it shinier? Put more acrylic on it. The more you put on, the deeper and shinier the floor becomes. However, if you want a longer product life, more is not better. The heavier and thicker the coats of sealer, the more vulnerable the floor is to scratching, cutting, scuffing and general wear.
Deep scratches are difficult to repair, and in most cases when tape is applied and then removed, the acrylic sealer (and quite often the stain) pulls off with the tape.
Acrylic sealers are breathable, and are much easier to strip and remove than epoxies and urethanes, but they don't provide very good protection from fats and oils
The initial installation should include 2 coats of solvent based acrylic sealer with 3 to 4 coats of sacrificial wax. The reason for using both solvent and water-based sealers is to allow you to strip the sacrificial wax only, and leaving the solvent based sealer. In theory, the solvent-based sealer won't strip off when stripping the sacrificial coats. Acrylic sealers do little to truly protect the concrete surface, If the sealer is allowed to wear through, you will immediately begin to wear off your concrete finish, including any stain or dye work that may have been done.
Eventually all of these coatings will have to be removed.
When calculating the cost of acrylic buildup, you must also remember that sealer is doing little, if anything, to actually protect the surface of the concrete. Another concern is when acrylics are applied over stained or decorative concrete, and you need to strip the damaged or worn sealer, you run the risk of damaging your art work and having to start from scratch, including the stain work. This can be very costly indeed.
Acrylic sealers have been shown to be less effective for high traffic and heavy load zones, so we have stopped using this process on commercial projects. We switched to surface hardeners for protection of the concrete surface. Occasionally we may provide the option to use an ultra thin film of water based sealer to provide a wet-look for stained interiors. (Or preferably a lithium-based copolymer technology, but more about this later).
On decorative concrete driveways, our biggest headache is tire marks. The compounds in the car tires are similar to acrylic sealers and leave black tire marks that are visually unappealing and a pain to remove. This problem is especially true in the summer when the paving and car tires are hot. In the winter, cars tend to peel out or burn rubber when the paving is wet, even when slip resistant additives are applied. Acrylic sealers are very slippery when wet and require a slip resistant additive for all outdoor use. I have discovered over the years that our clients don't like the plastic film gloss over their stamped concrete and prefer that we provide protection without the film coating. Most prefer a more natural stone look and don't care much for the annual reseal cost either.
The installation cost for acrylics is low, usually around $1.00 a square foot. And the annual reseal cost are usually between &
0.75 and $ 2.00 a square foot. In the long run, there is no more expensive form of floor and paving protection and coating than an acrylic sealer. Figure the 10-year cost on this see why.
Liquid Hardeners and Densifiers
The two older liquid Densifiers used for decades are sodium and potassium-based.
The newer high-performance hardeners use lithium technology. This class of product all densify and harden the concrete surface and effectively eliminate dusting and create a fairly nice appearing floor. Our ROCK HARD lithium premium densifier/Sealer develops a medium, easy-to-maintain sheen when regular maintenance discipline is followed. We have found that if the concrete surface isn't perfectly smooth to start with, the potential visual appearance of a chemically hardened and densified floor can be compromised. This is usually not a problem when creating an Rustic aged granite mottled patina finish.
The level of sheen is perfect for a natural stone look when applied onto stamped concrete
The big advantage to these products? Once they change the molecular structure of the concrete in the top surface to be harder and denser, the change is permanent. That makes maintenance from that day forward simple and inexpensive. Thin film coatings and waxes just lay there on the floor or Paving waiting to wear off. In contrast, a chemical densifier with proper care (which is minimal) reduces the long term maintenance costs and promises low cost, long-term performance that is clearly superior to other treatments. The current installed cost of a chemical densifier is $ 0.50 - $ 2.00 square foot depending on the size and condition of the job.
First-time application is relatively inexpensive, and gets less expensive over time. A good applicator with the right liquid hardener will deliver a floor that can last for decades. Most companies that deal in liquid hardeners offer a limited guarantee of 10 years or more. With regular cleaning (automatic scrubber and cleaning solution), the shine gets better over time. Slip resistance remains unchanged from the original bare concrete.
Since liquid hardeners do not leave a film, they are not glossy as newly applied epoxies, urethanes or waxes. In spite of the appearance, a treated floor will nonetheless be more durable and will maintain its dustproof protection for a very long time.
Why We Use Lithium
1. Lithium is non-expansive:
Older sodium and potassium silicates form an expansive alkali-silica gel in concrete that absorbs moisture and expands, and then dries out and contracts. This is why even properly cured concrete can develop crazing or map cracking after the application of sodium and potassium products. Lithium's reaction in concrete is non-expansive, so it won't contribute to crazing or map cracking. Lithium is also Green friendly to apply over traditional densifiers.
2. Less water soluble:
Lithium silicates do not absorb water like sodium and potassium products can. The resulting structure is more water resistant and easier to maintain.
3. Better Protection:
Lithium ions are smaller than sodium and potassium ions so they penetrate the concrete better. And lithium reacts more evenly throughout the wear surface. Sodium and potassium tend to react more violently and unevenly, leaving clumps of reacted and un-reacted calcium scattered throughout the wear surface. Lithium products are environmentally friendly. We use and strongly recommend our next generation decorative concrete floor and paving systems over thin film coatings for durability and low cost maintenance. Learn More On Ultimate Floor and Concrete Paving Protection Systems From AK4
1. Polished
2. Pentra guard
3. Rock Hard
Final Thoughts:
We believe there is going to be huge changes in the concrete surface protection industry. There are a lot of companies that make a lot of money selling you things that are expensive to maintain (acrylics) All petroleum based and resource depleting. Our aim is to provide you with the most advanced Eco- Friendly and easy to maintain products and systems available based on the SUSTAINABLE enviromental and cost efficent principal.
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