ACM/Alupanel Install
Alupanel is a very common material in the sign business. It has nearly replaced aluminum sheet metal due to its affordability and light weight. It is easy to install but must be installed correctly or wind may rip it down.
Metal Building Installs
When installing to an average corrugated metal building, rule of thumb is to have a screw every 2 feet or evenly spaced to the ribs of the building. We must screw to the high points or ribs, not the low flat points in between (See pics below)

When overall size is larger than one sheet will allow, we will use multiple sheets. Same rules apply, but with the addition that the seams must land on a rib and each corner of each piece must be screwed down. (See pic below)
Flat Building Installs (Brick or Wood)
When Installing to a flat building, where it is harder for wind to get behind the sign, less screws are required. As seen in the image below, each corner must be fastened as well as the center top and bottom of any sign over 4 feet. I would also suggest the center of each side for any size sign over 4 feet in height as well.