Does it pay to paint steel bin and warehouse roofs white to reflect solar radiation?
Yes. University research tests have documented that even new galvanized steel roofs absorb solar radiation almost as efficiently as black or dark green roofs. Old galvanized roofs absorb slightly more than new galvanized roofs. Painting galvanized bin roofs will lower headspace air temperatures by 15-20F (9-12C), which reduces the temperature of surface grain. All-white storage structures reduce solar gain and heating of sidewall grain, allowing grain temperatures to remain more uniform than in galvanized steel structures. It is good to wait until the oil from new galvanized roofs have oxidized before painting for best paint bonding.
