National Coatings Blog

Roof Coatings - Different Classes of Coatings

Posted by Nicole Gale on Thu, Jul 24, 2014 @ 08:34 AM

roof coatingsClasses of Coatings
Roof coatings can be classified into three types:  solvent, water-based, and 100 percent solids.  Solvent systems are those containing an organic solvent as carrier for the coating.  In this case, solvent evaporation causes the coating to form the membrane on the roof.  Water-based coatings employ water as this carrier.  The third class, albeit less common, is the solvent-free coating where two liquid components are premixed in a specially designed airless spray unit; a chemical reaction causes some of these two-part coatings to dry almost immediately.  Each of these three coating classes has specific advantages and disadvantages relating to the type and presence or absence of solvent.

Solvent Coatings
Coatings which employ organic solvents can be applied over a wide range of temperatures, including cold or marginal weather conditions.  Moreover, they will dry quickly under conditions of high humidity since the rate of solvent evaporation is not related to relative humidity.  These advantages are offset to some degree, however, because they contain large percentages of usually flammable, and sometimes highly toxic, organic solvents.

Additionally, many of these coatings are required to carry the D.O.T. classified "red label" associated with low flammability flash point.  This means the applicator must exercise care and prudent handling procedures when transporting, storing, and applying such coatings.  Also, since these systems contain organic solvents which may soften certain asphalt and other conventional roofing materials, they may cause "bleed through" problems or, even worse, permanent damage to the old roofing substrate.  Rooftop air intakes must be masked to prevent vapors from entering the HVAC and ventilation systems.

Finally, when using these materials, additional solvent is required to clean the application equipment after use.

Water-Based Coatings
In contrast, water-based coatings eliminate the flammability and potential toxicity hazards associated with solvent systems since they use water-rather than solvent-as the carrier.  Additionally, the equipment used can be easily cleaned with soap and water, and their potential for "bleed through" is significantly lower because they do not contain solvents.  Since water is an inexpensive solvent, cost is usually lower than solvent-based coatings.

The chief limitation of water-based coatings is the range of atmospheric conditions conducive to application.  First, they should not be applied at temperatures too close to freezing because the rate of water evaporation becomes so slow they may not dry properly.  Normal low cut-off point for application of these coatings is 50 degrees F.  Second, they should not be applied when rain or inclement weather is imminent.

Considerable progress in narrowing this application conditions gap between solvent- and water-based coatings has been made with a recent introduction to the marketplace of systems with "quick set" properties.  National Coatings AcryShield A600 and A640 have this property and can adequately withstand heavy dew or light rain shortly after application.

100 Percent Solids Coatings
The third, less common type of roof coating consists of 100 percent solids.  Since these coatings contain virtually no solvents, they do not possess the limitations of the water- or solvent-based coatings.  However, they do require special application equipment and are extremely sensitive to changes in application temperature as their ability to form a durable, long-lasting membrane is dependent on proper mixing ratios of the two components and reaction temperature.  If incorrect, the coating may not adequately cure or may, possibly, gel prematurely, thus preventing the protective membrane from forming properly.

Acrylic Coatings
Acrylic roof coatings take advantage of the inherent durability of acrylics, and can be designed to be very elastic and flexible over a wide temperature range for a relatively modest cost.  In addition, they are supplied as either water- or solvent-based products, although specialized acrylic coatings are available for roofs experiencing ponded water conditions.

For more information on roof coatings – download our FREE Brochure!
Looking for specific information on restoring a roofing substrate? Download one of our specific brochures:

Commercial Roofing Contractors

Cool Roof


Tags: Roof Coating Membranes, Roof Coating Systems, Roof Coating, Single-Ply Roof Coatings, SPF Roof Coatings, Asphalt Coatings, Hypalon Roof Coating, Roof Coatings for EPDM, TPO Roof Coating

Case History - Kaiser Permanente Antelope Valley Medical Office Building

Posted by Nicole Gale on Thu, Jul 10, 2014 @ 09:00 AM


Kaiser Antelope Valley4 small resized 600

Completed: June 2014
Contractor: Courtney Roofing
Size: approximately 50,000 SF
System: National Coatings SPF system with granule lock coat
Warranty Term: 20 years

Kaiser Permanente approached National Coatings requesting a roofing system with a 20 year warranty that could provide them with high reflectivity to combat the harsh Ultra-Violet rays from the high desert. It was also necessary that the roofing system delivers superior durability due to the roof having high foot traffic to be able to service the HVAC system and solar panels.

The goal was to combine both of these high reflectivity and superior durability properties into one system by embedding a course of granules between two coats of AcryShield A510 topcoat. This created a system where maximum reflectivity could be achieved while not sacrificing the high durability of a granulated surface.

Walkways were also installed by applying National Coatings AcryShield A550 for even more durability. The A550 was applied in a sand color to provide contrast creating a tan on white leaving Kaiser with very good looking rooftop.

For more information on our SPF Roofing Systems, download our FREE BROCHURE!

Kaiser Antelope Valley2 resized 600
Kaiser Antelope Valley3 small resized 600

Tags: Roof Coating Membranes, Roof Coating Systems, Roof Coating, spray roof coatings, AcryShield SPF Roofing System, SPF Roof Coating, Spray Foam Coating, SPF Roof Coatings

Spray Foam Roofing Coupled with Roof Coatings Guarantees Energy Savings

Posted by Nicole Gale on Tue, Mar 25, 2014 @ 08:00 AM

Spray Foam Roofing Coupled with Roof Coatings Guarantees Energy Savings while Cooling and Protecting your Building

spray foam roofing

Operational and building maintenance costs are increasing year after year primarily due to energy related expenses constantly rising. Building owners are frequently looking for ways to lower these costs without compromising their buildings safeguard and defense. With energy being the greatest controllable operating expenditure to a building owner, we suggest saving money while cooling and protecting your roof with the AcryShield Spray Polyurethane Foam (SPF) Roofing System.

A Promising Solution

spray foam roofingThe quickest and best way to cut energy usage and related costs to your building when needing a new roof is to get an AcryShield SPF Roofing System. This system has excellent adhesion over existing Asphalt, BUR, Concrete, Metal or Wood membranes - eliminating the need for a costly roof replacement. The SPF system is spray applied, creating a seamless, custom-tailored waterproofing roofing system to meet your buildings specific needs. During application, your business operations are conducted as usual, avoiding any need for business closure. The AcryShield SPF Roofing System uses a durable roof coating; high in UV blocking pigments to give your roof the added protection it needs from the sun’s harmful and damaging UV rays.

How do Spray Foam Roofing and Roof Coating Work Together to Save on Energy?

The AcryShield SPF Roofing System uses topcoats with high solar reflectance, protecting the building by reflecting the sun’s heat away from the structure; therefore, reducing heat transfer into the building, keeping the inside cooler.  These coatings also have high thermal emittance properties, which allows the small amount of absorbed heat that was not reflected immediately, to be radiated back into the atmosphere, again lowering the ability to transfer heat to the inside.

While the solar reflectance and thermal emittance properties can greatly reduce the energy demands of cooling the building, these are just the benefits of using a National Coatings elastomeric roof coating.  Let’s take a look at the benefits of spray foam. The spray foam roofing provides high performance insulation to the roof. This reduces the buildings ability to lose or gain heat, keeping a constant ideal temperature inside the building with less need to use the air conditioning or heating systems.

Now that we know you can conserve energy with roof coatings and spray foam roofing separately, it is easy to determine that by combining the two, your building will conserve an even greater amount of energy. The AcryShield SPF Roofing System specifically can reduce your energy consumption and costs up to 30% per year. This is a huge reduction in cost based off California’s energy-efficiency movement - Flex Your Power© which states “A 30% reduction in energy consumption can lower operating costs by $25,000 a year for every 50,000 square feet of office space.” If you are interested in additional information on Spray Foam Roofing and the Benefits of Coating an SPF Roof, download our FREE Guide.   


SPF Roof Coating

Tags: Coating Systems, Cool Roof Coating, cool roof coating information, White Roof Coating, Cool Roof, spray roof coatings, AcryShield SPF Roofing System, SPF Roof Coating, Spray Foam Coating, spray applied roofing, SPF Roof Coatings, Protecting a SPF Roof