Mascoat’s WeatherBloc-HRC is the latest product in a family of high-quality reflective and thermal insulating coatings to offer the best in protection against heat transfer for roof and sidewall applications. The coating was specifically formulated to combat radiant heat gain and solar loading for all climates. The coating offers outstanding temperature differentials with just a single coat application.

WeatherBloc-HRC differs from reflective roof coatings by employing Mascoat’s high-performance insulation particulates, providing additional thermal performance. WeatherBloc-HRC uses ingredients that produce a low thermal heat flux across its surface, whether it is applied on top of OR under a roof surface. Typical rooftop coatings solely use their white appearance to reflect solar loading, while WeatherBloc-HRC’s unique design can keep the heat out, even on a cloudy day. And unlike standard reflective rooftop coatings that become less effective when dirt and grime accumulate, Mascoat WeatherBloc-HRC will continue to perform even if dirty!


Surface Preparation

All substrates should be cleaned prior to application of product, Most substrates need a pressure wash.

Concrete Surfaces

Due to the porous nature of concrete/cement, coverage rate variations should be taken


Only mud mixing paddles, available from Mascoat, should be used to mix the contents


On clean surfaces, primers are not needed except on carbon steel on HRC


Half-face respirator recommended with ammonia cartridge or better. Eye protection recommended

Airless Sprayer

This sprayer is the best method for application of the coating and need capacity of 1.0 gallon per minute .

Brushing and Rolling

Except for small touch-ups of less than 0.5 ft2 (0.04 m2), it is NOT recommended to brush on HRC


All equipment can be cleaned with soap and water, all data on this sheet was collected using ASTM

WeatherBloc-HRC is used to combat heat transfer and protect substrates. Typical applications include: • Rooftops • Walls • HVAC systems • Roll-up Doors • Interiors • Exteriors • And much more...


Mascoat WeatherBloc-HRC thermally protects a structure from heat in multiple ways unlike reflective rooftop coatings, which only reflect sunlight to reduce solar loading. Its bright white coloring reflects upwards of 85% of the solar radiation like standard reflective coatings, but there’s more to the coating than just coloring. It also contains irregularly-shaped ceramic and silica particles that help greatly reduce the amount of heat transfer through the coating. This high content of entrapped air blocks thermal transfer very efficiently. While reflective coatings only recommend one coat because they are solely relying on reflective properties, an extra coat of WeatherBloc-HRC will give you enhanced performance. The coating will help reduce heat transfer even if it becomes dirty or is placed on the underside of a roof!

The combination of these factors allows for enhanced thermal dissipation across the surface of the coating. WeatherBloc-HRC’s unique composition makes it extremely efficient for its thickness, resulting in less thermal transfer into interior spaces than standard reflective coatings.


Since WeatherBloc-HRC works to reduce the heat transfer through the coating instead of just reflecting UV rays, it will perform better, especially as ambient temperatures increase. This chart shows that while a standard white roof coating in perfect condition will help decrease the amount of heat passing into interior spaces, a great deal of energy can still pass through, keeping interior temperatures high. Thanks to the insulating particles described above, WeatherBloc-HRC will help reduce heat transfer even further, keeping interior temperatures more manageable. Moreover, WeatherBloc-HRC will still provide an insulation value, even when dirty or on cloudy days.


  • Reflects and reduces heat transfer efficiently

  • Protects substrates

  • Improves roof aesthetics

  • Non-toxic and lightweight

  • Quick and easyapplication

  • Provides substrate protection

  • High build ability

  • Offers sealant quality

  • Reduces expansion and contraction

  • Ultra-Low VOC content



DRY COAT THICKNESS 0.38 mm (15 mils) 0.5 mm (20 mils) 0.75 mm (30 mils)
SQUARE METER 31–34 22–25 15–17
SQUARE FEET 333–366 250–275 166–183

Note: Thicker coats will enhance coating’s thermal performance.