Three recent app releases aim to raise the bar on roof-estimating tools. Two of them are free and modest in function, although one reaches for the stars. The other is pricey and complex by app standards. Photo by Tom Sawyer PITCH PERFECT Pitch Gauge 2.0 has a calculator that converts measurements into estimates of materials. One roofing contractor calls it a must-have. At the modest end of the spectrum is a roof-pitch-measuring app called Pitch Gauge 2.0, which came out this month for Android smart phones. The app, also available for the iPhone, uses the smart phone's gyroscope to read
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.