Designing for year-round longevity and sustainability

By Emma Peterson. 

How Tremco engineers high-performance coating systems that extend life, cut costs and reduce waste. 

In recent years, roof coatings have become one of the popular avenues to not only save a building owner money on their roof, but also to build more sustainably. But a roof coating project is not as simple as painting a roof white. To learn more about the many factors that play into applying coatings to roofs, we sat down with Richard “Rich” Crawford, energy engineer at Tremco. He described his role, saying, “I perform on a national and international level various roof energy, financial/lifecycle, sustainability, dew point and vapor drive analyses to help problem solve and recommend solutions for building envelopes.” 

When Rich was first hired at Tremco in 2008, he was focused on doing energy audits for customers. He explained, “I was hired and trained to perform whole building energy audits looking at the building envelope, lighting, HVAC, ventilation, solar and water. We then bundled the energy cost savings from these various solutions to help customers pay for expensive roof replacements.” 

As the demand for roof restoration coatings increased over the years, this resulted in increased requests for estimated roof energy savings for restorations and comparing them to roof replacements. Back then energy savings were estimated using online calculators.  Because of various limitations, Rich developed a more sophisticated energy model that looks at savings on an hourly basis. He explained, “It's hourly. I can tell you what's going on with the roof every hour of the year. You know, February in the middle of the night, for example. What happens when the sun is on it? What if you change the color?”  

How does this model work? It’s based on three main factors – solar radiation, convection and thermal conductivity and in that order. Rich elaborated, “First, you have the solar radiation component, which is mostly related to roof membrane color.  The darker the roof membrane, the hotter the roof membrane will get, increasing the amount of heat (energy) that could get transferred through the roof assembly.  The second component is convection, which is mostly affected by the wind and serves to cool the roof membrane by carrying heat away as it blows across.  The third and resulting component is thermal conduction which is mostly affected by the amount of thermal insulation or R-value and serves to reduce the amount of heat flowing through the roof assembly, ultimately affecting the energy bill. How do you estimate the energy savings from that?” Other factors that must be included in these calculations include existing and proposed roof construction, roof area and building height, local weather and utility data, HVAC efficiencies, proposed cost of solutions and more. 

Over the years, Tremco has developed high-performance restoration products that extend the longevity of a roof restoration solution from 10 to 12 years to up to 20 years and beyond. In addition to this extended longevity, these coatings also bring sustainability and economic benefits. Rich gave an example, sharing, “With roof restoration solutions that can now go to 20 years or more and with Tremco’s reinforced fluid applied restoration technology, we can give restored roofs new life in the future with just a topcoat... With that method you completely avoid sending the old materials to the landfill and you also get additional embodied energy savings.” These embodied savings refer to the reduction in greenhouse gases in the production of creating a topcoat versus a whole roofing system. For example, when creating an entire system, you need energy to manufacture polyiso insulation, cover boards and membranes from scratch and then transport them to location. With a future topcoat, you make one product that is easily transported to location – using far less energy and therefore emitting fewer greenhouse gases in production. 

And the simplicity of the restoration process in comparison to the reroofing process not only benefits the environment, but it also benefits the building owner’s wallet. Rich gave an example, “Let’s say that restoration costs you $15 per foot, in comparison the cost of replacing would be $25. That’s already 40% of savings right there!” And those savings just grow over time. Rich explained, “Let’s say you installed a Tremco restoration system and saved 40% of costs. Now, 20 years later when you need to work on the roof again, a replacement will have more than doubled in cost due to inflation. But, since you already have a Tremco system on the roof, all you have to do to restore it, is simply topcoat it. The cost of that topcoat by itself is low, probably about half in comparison to the $15 per foot when you first installed it. So, we add inflation, it doubles, you’re still looking at $15 versus $50.” All of this to say, the cost savings in relation to choosing restoration over replacement is exponential over the course of a building’s lifecycle because of factors like inflation. Rich put it best, “Overall, my analysis on these projects usually finds that through cost avoidance they will pay for themselves.”