When it comes to choosing roofing and waterproofing materials, the decisions can be crucial. It’s estimated that 60 percent of litigation claims related to buildings involve the roof, and anyone who’s excavated landscaping to address a below-grade waterproofing issue knows how expensive that process can be.

Roofing and waterproofing professionals all rely to some degree on field testing and laboratory testing to make decisions about which product might perform best for a given project. But how can we make sure those tests are relevant and accurate? Everyone’s heard the old adage about comparing apples to apples, but in the real world it’s hard to get performance data that’s set up under the exact same criteria. A roof in Seattle faces different conditions than a roof in Texas or Minnesota. The roof of a warehouse faces different conditions than the roof on top of a manufacturing facility, a restaurant or a condominium.

Which tests are required and how those tests are conducted are important, too. As the article titled “Putting Membranes to the Test” shows, products from different categories can be subjected to different tests. Relatively new products such as single-ply membranes are subjected to longer-term UV and thermal aging to predict performance, while modified bitumen membranes, which have been around longer, generally use black-oven aging to accelerate performance. Differences like this can makes it difficult to differentiate between products. And it’s not just single products that have to be compared, but entire systems.

True apples-to-apples comparisons don’t come around very often, but when they do it’s nice to see someone take advantage of them. When four almost identical buildings at a correctional facility in upstate New York needed re-roofing, they presented a perfect opportunity to compare the performance of four different roof systems. A team of professionals was able to do just that — and install testing equipment to measure performance. For more detail on the research study, check out Jim Kirby’s article titled “Green, Greener, Greenest.

It’s fascinating data. Now all you have to do is figure out how to recreate this study in your neighborhood.

 Chris King