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APF SEALER SYSTEMS
Two coats APF Acryseal (third coat optional)
Application -- Surface must be completely dry. Product applied at the rate of
250-350 sq. ft. per gallon per coat depending upon the porosity of the substrate. Two coats will normally produce a soft sheen. Gloss and cleanability are improved by a third coat.
Performance Expectations -- Material is easy to apply and dries quickly for recoating. Penetrates and adheres permanently to all properly prepared architectural concrete surfaces. System gives good overall performance for residential and light commercial applications. Performance in vehicle traffic areas is moderate. Use in heavy foot traffic areas requires regular maintenance coating. Recoating with a material other than itself requires thorough mechanical abrading or the use of a Polyurethane 250 tie coat to insure intercoat adhesion. Enhances colors and darkens the host surface.
Recommended Uses -- Used as a sealer system over colored concrete, acid stains and polymer concrete.
Two coats Polyurethane 250
Application -- Surface may be damp, but with no standing water. Product applied at the rate of 250-350 sq. ft. per gallon depending upon the porosity of the substrate. May be recoated after 1-2 hours depending upon temperature.
Performance Expectations -- This system is used in place of Acryseal when a general performance upgrade is desired, but a high build sealer system is not required. Compared to Acryseal, Polyurethane 250 has better initial gloss and gloss retention, improved abrasion and stain resistance and better performance in vehicle areas.
Recommended Uses -- Used as a sealer over colored concrete, acid stains and polymer concrete.
Two coats AU1000 (polyurethane finish coat optional)
Application -- Surface may be damp, but with no standing water. Product applied at the rate of 250-350 sq. ft. per gallon per coat depending upon the porosity of the substrate. Two coats will normally produce a soft sheen. Water-based polyurethanes may be applied as soon as the previous coat of AU1000 is tack free (usually 30-60 minutes). Allow AU1000 to cure overnight before application of a solvent-based polyurethane finish coat.
Performance Expectations -- AU1000 will not penetrate dense surfaces as well as solvent sealers or epoxy materials. Adequate adhesion is achieved on porous substrates. Gives overall performance similar to solvent acrylic sealers. Not recommended for use in areas exposed to continuous water. Wear characteristics dramatically improved with the use of a polyurethane finish coat. Provides slight color enhancement, little darkening of the host surface.
Recommended Uses -- Most common use is over porous polymer modified concrete. Not recommended over denser surfaces or acid stains.
AE Clear Prime, with Polyurethane 500 or 700 finish coats
Application -- Surface may be damp but with no standing water. Acid stained surfaces must be properly neutralized with ammonia or APF Super Base Neutralizer. AE Clear prime should be applied at 250-300 sq. ft. per gallon and can be recoated after 30-60 minutes depending upon temperature and humidity. Two coats of Polyurethane 500 or 700 should be applied at 350-400 sq. ft. per gallon per coat.
Performance Expectations -- This water-based system is suitable indoors or outdoors and is generally used where solvent odors cannot be tolerated. AE Clear Prime offers excellent adhesion over reasonably profiled surfaces but should not be used over dense, non-porous surfaces. AE Clear Prime does not darken the host surface like solvent-based sealers.
Polyurethane 500 and 700 are solvent free, user friendly materials with excellent hardness and abrasion resistance. Polyurethane 700 is less expensive and gives a faster dry. Polyurethane 500 offers better gloss and abrasion resistance to heavy foot traffic. Neither material is suitable for vehicle traffic areas.
Recommended Uses -- Used over acid stains or profiled colored concrete where solvent odor cannot be tolerated.
Polyurethane 250 primer with Polyurethane 100 or 200 finish coats
Application -- Surface may be damp, but with no standing water. Apply Polyurethane 250 at the rate of 250-300 sq. ft. per gallon. May be recoated after 1-2 hours depending upon temperature. Apply Polyurethane 100 or 200 at the rate of 250-350 sq. ft. per gallon. A second coat is optional and increases the gloss and overall performance.
Performance Expectations -- Polyurethane 250 adheres tenaciously to a wide variety of surfaces and may be used in exterior applications. Polyurethane 100 and 200 are solvent-based catalyzed materials used in vehicle or high traffic pedestrian areas. Polyurethane 100 is the preferred material for resistance to foot traffic abrasion. Two component polyurethane materials offer the ultimate in exterior durability, gloss retention and ease of cleaning.
Recommended Uses -- Used as a high performance, high build sealer system over interior or exterior colored concrete, acid stains and polymer concrete.
Epoxy 200 or 400 Primer with Polyurethane 100 or 500 finish coats
Application -- Epoxy 200 may be applied to damp surface, but standing water must be removed. Epoxy 400 must be applied to a dry surface and may be reduced with 10-15% solvent if desired. Apply Epoxy 200 at the rate of 200-300 sq. ft. per gallon. Epoxy 400 can be applied at 200-300 sq. ft. per gallon. . Epoxy 200 cures in 1-2 hours for recoating and Epoxy 400 cures in 6-12 hours depending upon curing agent selection.
Polyurethane 100 should be applied at 300-350 sq. ft. per gallon. Polyurethane 500 should be applied in two coats at 350-400 sq. ft. per gallon per coat.
Performance Expectations -- Using Epoxy 200 as the primer provides excellent adhesion and fast turnaround. Epoxy 400 gives excellent adhesion and higher film build. Epoxy materials may darken the host surface more than solvent sealers. When used over green colored acid stains, epoxy primers will give the stain a blue look. Both Polyurethane 100 and 500 are excellent for resistance to foot traffic abrasion and easy cleanability.
Recommended Uses -- Used as a high performance sealer system for over interior applications only. May be used over any architectural concrete surface.
FACTORS TO CONSIDER WHEN SELECTING A SEALER SYSTEM
1. Obtaining successful substrate adhesion - Different architectural surfaces present different degrees of adhesion difficulty. It is generally very easy to adhere to polymer concrete surfaces because of their porous nature. On the other hand, smooth troweled, color hardened concrete is very dense with little porosity and will limit the choice of sealers to those materials with better penetration and adhesion capability. We have found that architectural concrete surfaces colored with dry shake-on materials can be especially troublesome if all of the colorant has not been thoroughly incorporated into the surface. The colorant can then act as a "bond breaker" and must be removed before sealer application. Acid stained surfaces may present adhesion challenges for water-based sealers because acid staining can create a pH imbalance in the substrate that can interfere with proper film formation and adhesion of water-based materials.
In general, water-based sealers do very well over textured, porous surfaces but are not recommended over dense, unprofiled substrates. Solvent-based sealers and epoxy materials generally offer the best adhesion to a greater variety of surfaces and are the products of choice over more challenging substrates. Epoxy materials are limited to indoor use. If you are unsure about sealer adhesion over a certain substrate, it is advisable to conduct adhesion testing prior to final product selection. There are two types of tests that can be done. A tape pull adhesion test (ASTM D 3359-90) will give a general idea of adhesion capability and usually expose glaring adhesion problems. An adhesion testing instrument such as the Elcometer 106 will quantitatively measure the psi necessary to separate the sealer from the substrate (ASTM D 451).
2. Protecting the decorative substrate - Architectural concrete surfaces must be protected from foot traffic abrasion, vehicles, automotive chemicals, etc. Each application has its own unique exposure and each sealer system will provide different degrees of protection.
Resistance to abrasive foot traffic is very important in sealer selection for public areas such as restaurants, hotels, casinos, etc. that receive high volumes of foot traffic. A poorly designed sealer system in these areas would be quickly compromised resulting in damage to the decorative work underneath. Once this occurs, effective repair of the decorative effect can be very difficult.
How much abrasion resistance a given sealer provides is a function of the amount of material deposited on the surface (film thickness) and the inherent resistance properties of the polymer material (usually measured by Tabor Abrasion Testing). In general, single component materials will provide adequate protection in residential and light commercial applications. Two component materials are chemically crosslinked and provide tougher, more abrasion resistant film properties. Epoxies and especially polyurethanes are the products of choice to protect against heavy foot traffic abrasion.
Vehicle traffic is not as abrasive as heavy foot traffic, but if the sealer is too soft, permanent tire tracking may occur. Single component solvent acrylic sealers will not resist gasoline or brake fluid. These materials may destroy the sealer and damage decorative work underneath. Two component polyurethanes resist tire tracking and automotive fluids and offer the best performance in vehicle areas.
3. Achieving the desired appearance - Solvent-based sealers and epoxy materials will deepen and enhance substrate colors. This "popping of the color" is often considered desirable. Water-based sealers provide much less color enhancement and are said to "lock in" existing color. If the surface is water-based, however, water may migrate through pinholes or microcracks in the sealer, or through joint areas and darken the substrate. The darkening typically leaves when the surface dries, but this phenomenon may still be considered objectionable to some customers.
The level of gloss may be an important factor in sealer selection. In general the crosslinked epoxies and polyurethanes are inherently glossier than single component materials. Polyurethanes retain their gloss under foot traffic better than other polymers and are unexcelled for long term exterior gloss retention.
Sometimes high gloss is not desired. Flattening agents can be used to reduce the gloss of acrylic or polyurethane sealers.
4. Maintenance Considerations - Cleanability, stain resistance and recoating intervals are also important factors in selecting a sealer system. Solvent-based acrylic sealers have been popular for years because they offer reasonable cleanability and stain resistance and are easy to recoat. However, in demanding areas recoat intervals tend to be short.
Once again, two component polyurethane has proven to be the superior material for cleanability and stain resistance. It will also keep its gloss for an extended period of time under heavy foot traffic.
Many architectural concrete contractors have taken the approach of initially using an inexpensive sealer system and recommending a waxing maintenance program for the end user. Another option would be to apply high performance polyurethane top coats initially and periodically recoat with a fast dry, non-sacrificial water-based polyurethane. This relieves the customer from the expensive burden of the wax-strip-wax cycle.
APF MATERIALS
Arizona Polymer Flooring has been directly involved with the application, formulation and manufacturing of sealers and coatings for concrete for nearly 25 years. Our products are based on leading edge epoxy, polyurethane and acrylic polymer technology. The following is a brief description of the materials we offer for application over architectural and decorative polymer concrete:
1. Epoxy 200 -- Water-based material used as a rapid curing primer for interior applications. May be applied to damp surfaces. Intensifies colors in decorative substrates.
2. Epoxy 400 -- Low viscosity, 100% solids material used as a primer or high-build intermediate coating for interior applications. May be reduced 10-15% with solvent when using as a primer. Intensifies colors in decorative substrates.
3. APF Acryseal -- Solvent-borne acrylic available in 20% and 28% solids version. Used as a sealer over a wide variety of surfaces. Fast drying, low cost, easy to use. Excellent adhesion to most cementitious surfaces. Available in gloss or satin. Intensifies colors in decorative substrates. Moderate performance in high foot traffic or vehicle areas. Recoating with other materials requires thorough mechanical abrading or the use of a Polyurethane 250 tie coat to insure intercoat adhesion
4. AU1000 -- Water-based styrene acrylic used as a cost-effective sealer over porous polymer concrete in light traffic areas. Fast drying, low cost, easy to use. Not recommended for vehicle areas or over acid stains. Performance enhanced by the use of a polyurethane top coat. May be applied to damp surfaces. Gives only slight color enhancement over decorative substrates.
5. AE Clear Prime -- Water-based, two component acrylic-epoxy used as a primer over a variety of surfaces including properly neutralized acid stains. Material dries quickly and has better adhesion than acrylic or polyurethane emulsions. May be applied to damp surfaces. Gives only slight color enhancement over decorative substrates.
6. Polyurethane 100 -- Two-component, solvent-based, VOC compliant polyester-urethane used as a high performance finish coat in heavy foot traffic or vehicle areas. Gives more film build than Polyurethane 500. Available in gloss or satin.
7. Polyurethane 200 -- Two-component, solvent-based, VOC compliant acrylic-urethane for use in vehicle areas and areas subject to moderate foot traffic. Available in gloss or satin.
8. Polyurethane 250 -- Two-component, VOC compliant primer/sealer for use over all architectural concrete surfaces - especially effective over acid stains. Outstanding adhesion to challenging surfaces including damp concrete, solvent acrylic sealers and fully cured polyester-urethane. Compared to solvent acrylic sealers, gives superior gloss, exterior gloss retention, cleanability and wear resistance.
9. Polyurethane 500 -- Two-component, water-based polyester-urethane used as a high performance finish coat where solvent odor cannot be tolerated. Excellent abrasion resistance and gloss retention under heavy foot traffic. Not recommended for vehicle areas. Available in gloss or satin.
10. Polyurethane 700 -- Two-component water-based acrylic-urethane used as a fast drying finish coat over a variety of primers. Very hard material with improved mar and abrasion resistance compared to single component epoxy materials. Not recommended for vehicle areas. Easy to use, excellent as a high performance in-house maintenance coating. Available in gloss or satin.
SURFACE PREPARATION
As with all specialty coating applications, proper surface preparation is a crucial element of success. Surfaces to be sealed or acid stained must be clean and free of unsound materials or contaminates that may weaken the adhesion of the system. Mechanical or chemical profiling is not normally done to decorative surfaces because these methods can alter the surface coloration or render an acid stain ineffective. Scrubbing the surface with a floor machine using an aggressive nylogrit brush is the best surface preparation. Use a good commercial cleaner such as APF Orange Clean reduced 8-1 with water. Do not let the cleaning solution dry on the surface. Rinse thoroughly to remove any possible detergent residue. Rinsing with a pressure washer is ideal.
Surfaces that have been acid stained must be properly neutralized with a strong base solution such as ammonia or APF Super Base Neutralizer and rinsed well. Water-based coatings applied to improperly neutralized stained surfaces are subject to premature failure. Freshly placed polymer concrete requires no surface preparation.
MOISTURE VAPOR TRANSMISSION
All interior concrete floors not poured over an effective moisture vapor retarder are subject to possible moisture vapor transmission that may lead to blistering and failure of the sealer system. Excessive vapor transmission occurs when there is a source of water under the slab combined with concrete that is unusually permeable. The source of the water may be a high water table, broken water pipe, landscape sprinklers or seasonable rains. Overly permeable concrete usually results from a water/cement ratio that is too high. The excessive water leaves the slab during the curing process and creates capillaries that serve as the pathway for water vapor to be drawn up through the slab. This vapor carries destructive alkaline materials that accumulate at the interface of the sealer and substrate and may cause a loss of substrate integrity, which leads to a loss of bond for the sealer.
The only method of determining how much moisture vapor is passing through the slab is the calcium chloride test. This test gives a measurement of how many pounds of vapor pass through a 1,000 sq. ft. area in a 24 hour period. Readings of 3 and below are considered safe. Higher readings require some type of remedial treatment to get the slab into compliance. There are many approaches to this remediation. Contact APF for additional information.
The key points for the architectural concrete contractor are these:
1. If you have input into the initial concrete pour, be sure to specify a good vapor retarder and keep the water/cement ratio at acceptable levels.
2. Conduct your calcium chloride tests. These tests are available through APF.
3. Address vapor emission transmission in your warranty. Since your calcium chloride testing is only accurate at a given point in time, you cannot control possible future problems if the vapor transmission rate changes.
OVERVIEW
In recent years architectural and polymer modified concrete has gained increasing acceptance in both the commercial and residential markets. Architectural concrete is conventional concrete that has been colored with dry-shake hardeners, integral color or stains. It is often stamped or imprinted to simulate tile, stone or brick. Decorative sawcutting and sandblasting may be used to create a variety of artistic effects.
Polymer modified concrete has improved properties compared to conventional concrete and is normally installed as a 1/16 - 1/2 inch decorative overlay on existing concrete slabs. It may be either the self-leveling type or a troweled-in-place system. Like architectural concrete, it can be integrally colored, stamped or stained to create many beautiful looks.
For the purposes of this discussion, the difference between penetrating sealers and high build sealers needs to be established. Penetrating sealers are low viscosity materials that fill the pores of the substrate to some degree, but do not leave a polymer film above the peaks of the concrete. A typical penetrating sealer system would consist of two coats of a 15-25% solids material applied at 250-350 sq. ft. per gallon. This would leave 2-4 mils of material in the pores of the concrete and normally have little effect on the original texture of the surface. High-build sealers are applied more heavily than the penetrating materials and are designed to build a surface film. A typical high-build sealer system would consist of 2-3 coats of 35-60% solids material spread at 200-300 sq. ft. per gallon leaving a total thickness of 5-12 mils. High-build sealer systems provide better protection of the substrate and better cleanability than penetrating systems, but create a smoother surface that is more likely to present a slip hazard under wet conditions. The important issue of slip-resistance is addressed in a companion technical paper "Measuring Surface Traction and Engineering for Slip-Resistance."
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