Drywall Calculator Jeremy Breaux Price: 99¢Platforms: iPhoneThis app makes relatively simple calculations even simpler. To figure out how many sheets of drywall will be necessary for a given room, all the user has to do is input the height and perimeter of the walls and the length and width of the ceiling. The tool can exclude some areas of the room and allow for slope. The app gives total drywall area in square feet and tallies the number of 4-ft-wide by variable-height sections needed. Users must enter fractions as decimal points, which one app reviewer thought preposterous. n9/11 MemorialNational
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.