The most common architectural sheet metal gauge sizes are 18, 20, 22, 24 and 26, according to NorthClad.com in 2012. Vista-Industrial.com lists some gauges for common sheet metal types for steel and aluminum ranging from seven to 28, as of 2016.
NorthClad.com notes that 18, 20, 22, 24 and 26 are the only gauges available in most prefinished materials. Structural components use heavier materials and thinner materials lack the strength for most architectural uses. Vista-Industrial.com lists 13 common steel sheet metal gauges and 11 common aluminum sheet metal gauges. The steel gauges range in thickness from 0.015 inches to 0.1874 inches. The aluminum gauges range from 0.025 inches to 0.190 inches.