Arizona State University, Phoenix, and 3M test a 'cool roof' coating at an outdoor shelter to reduce heat for the homeless.

Metal roof pros include durability and a 50-year life span, but they are more expensive than asphalt shingles.

The conical nozzles emit a very soft pattern that doesn’t “blow past” a narrow piece of metal, allowing the charged particles to adhere to the surface. All powder coating guns have electrodes and ...