Simple Solutions to Complex Roofing Problems: Black vs. White Roofing 

In this era of continued rising energy costs and concerns about the environment, choosing the right roofing system is often a complex problem that contractors, architects, building owners and specifiers face. The simple solution to this challenge has somehow evolved to be: “White is always right.” The white roof bandwagon has gained so much steam, that some cities are even saying that slapping white paint on a dark roof will solve problems ranging from saving energy to eliminating the heat islands that are melting the ice caps.

The “white is right” mandate is now getting a long second look.  Now that it has been put to the test in the real world, the empirical data is causing many authoritative roofing experts to say, “Not so fast.” Tom Hutchinson, a nationally recognized consultant on roofing issues, even said, “Attempting to effect change with a single component mandate is a faulty approach.”

Key Questions to Ask Before Deciding What’s Right For Your Property.

Despite the complexity of the challenge, there are key questions that can help building professionals clarify their construction needs and select a suitable roofing system. These questions don’t deal directly with roof color, but they do provide important guidance about whether to use a black or white membrane in specific situations

1.  “Does the climate in the geographic area where I am installing a roofing system demand more heating days or cooling days?”

In other words, “Am I going to spend more money in the winter heating a building with a reflective roof than I am going to save on air conditioning costs in the summer?” This question is especially pertinent in cool Northern climates, where building owners spend up to five times more on heating their buildings than on cooling them. In these situations, common sense tells us that a reflective roof may actually increase energy costs, energy consumption and carbon emissions. Hard science supports the same conclusion: A landmark study from the University of Kansas in 2010 concluded that when white roofs are used in Northern climates, “Global space heating increased more than air conditioning decreased, suggesting that end-use energy costs must be considered in evaluating the benefits…”

2. “What type of insulation will be used, what is the R-value, and how many layers will be installed?”

State-of-the-art research is revealing that insulation levels are equal to or more important than roof color in affecting energy efficiency in a structure. Additionally, appropriate levels of insulation can mitigate the condensation problems that have been associated with white roofs in cooler climates. Mike DuCharme, Director of Product Marketing at Carlisle SynTec Systems, said, “It’s important to look at all of the factors involved when you are choosing a roof. Assess all of your costs – insulation, roof membrane, projected energy use – and then make your decision. For instance, EPDM roofing membranes are available in both black and reflective white. But it’s important for the designer to work with the roof membrane manufacturer to determine the best choice for your specific climate, and the best combination of roof color and insulation R-value.”

3.  “How long will the roof last?”

This very simple question is often overlooked in discussions about sustainability. Common sense tells us that a roofing system that lasts a very long time makes less of a dent on the environment and the budget vs. a roof that has to be replaced frequently. Recent studies have shown that black EPDM will last in the field for more than 30 years, and in laboratory tests for 50 years. “The bottom line is that the durability of EPDM makes it a smart long-term option one can’t afford not to consider,” said Jennifer Ford-Smith, Director of Marketing and Single Ply Product Management at Johns Manville.

Bottom line

“Building owners have more choices than ever.  We know that there is an EPDM roof for every climate. EPDM has a proven track record of performance in all areas of North America and around the globe. A white surfaced roof is not automatically the best choice.  Of course, the most economical approach is to always care for the roof you have and prolong it from being placed in a landfill.”

Posted in NIR Blog.