National Coatings Blog

More than likely, you have a building with a low-sloped roof or a steep-sloped roof. How can you tell the difference? As defined by ASTM Standard E 1918-97, a low-sloped roof has a surface with a slope of 2:12 inches or less and a steep-sloped roof has a slope greater than 2:12 inches.

Low sloped roofs are sometimes referred to as a flat roof; however, the pitch on a low-sloped roof is greater than that of a flat roof, which is 0 inches to 2 inches. Low-sloped roofs are designed with some pitch, to allow water to flow off the rooftop into a proper drainage system. A dry rooftop ensures the roof will remain durable and watertight. Ponding of water can increase the likelihood of a leak, and can promote algae, mold, or other plant life to grow, causing damage to the roofs surface.

Often times, low-sloped surfaces have one of the following roofing products on them: Roof coating systems, single-ply membranes (EPDM, Hypalon, TPO and PVC), asphalt, built-up-roofs (BUR), modified bitumen or mod bit, spray polyurethane foam (SPF), or metal. A low-sloped roof also has components such as flashings, copings, and drains.

Low-sloped roofs can greatly benefit from reflective roofing products by creating a cooler indoor ambient air temperature, lowering energy utility bills and lengthening the lifespan of the roof. The easiest and most cost effective of these products to install would be a Cool Roof Coating System because it can be installed directly onto the existing roof membrane without needing to tear-off the existing roof. Cool Roof Systems also do not require businesses to close during installation as they are non-disruptive.

For additional information on roof coating systems, reflectivity and Cool Roof Coatings, download our FREE Product Brochure.

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There are two types of roofs: low slope, (which is often referred to as a “flat roof”) and steep slope roofing. Low-slope roofs are less than or equal to 3:12 or 14 degrees in slope and steep slope exceeds 3:12 or more than 14 degrees in slope.

Flat roofing systems that can be installed on a low-slope rooftop include: 

• Asphalt Membranes – Including Built-Up (BUR), Mod Bit and Cap Sheet
• Metal Systems
• Roof Coatings
• Single-Ply Membranes – Including EPDM, Hypalon, PVC and TPO
• Spray Polyurethane Foam (SPF) Systems 

Like all roof materials, these flat roofing systems provide weatherproofing, reinforcement and surface protection. Low-sloped roofs have an asphalt, metal, single-ply or SPF roofing system initially installed on top of it. A roof coating system is often added on top one of those systems for an increased roof lifespan, energy savings, protection, maintenance and/or restoration.  

Roof coatings can be added during the construction phase to increase reflectivity, provide additional protection and decrease energy consumption. Coating an asphalt roof covers the black surface of the roof and creates a white rooftop, which allows the building to remain a cooler temperature without the extra use of air conditioning. (Check out our graphic showing how a “Cool Roof” saves a substantial amount of money versus a “Normal” aka black roof.) Coatings are also added during the construction phase onto SPF systems to protect the foam from the sun’s harmful UV rays. The UV rays would cause premature degradation to the foam, if the foam wasn’t covered and protected by the coating. This is a necessary step to applying a spray polyurethane foam system to any rooftop. 

Roof coatings are also applied onto these flat roofing systems when initial signs of degradation and failures occur. The coating systems are able to restore and renew these flat roofs to new without a costly tear-off, without business closures or disruptions and for a very competitive cost. The roof coatings extend the lifespan of the roof up to 20 years and can be re-coated every 10 or so years to restore your existing roof indefinitely. This can save you thousands of dollars by avoiding a traditional roof replacement. Read our article: Life Cycle Cost Analysis Using Roof Coatings for a detailed cost analyses.

If you are interested in more information on roof coatings for flat roofing systems, download our Free Product and Application Brochure, or our Considering Coatings – a Free Guide to Roof Coatings.

For information on coating a specific substrate:

• Asphalt
• Metal
• Single-Ply
• SPF