In my fledgling days in the pole building industry, we jumped on board when ASC Pacific began offering “Twice the Life” Zincalume® coated steel roofing panels as an alternative to bare galvanized. Keep in mind, back in the early 1980’s almost every roof was unpainted – so this was huge!

One side benefit of Zincalume® is the aluminum content of the protective coating causes the bare panels to oxidize to a milky white over time, unlike the red rust of galvanization. One prolific Pacific Northwest builder even sold Zincalume® to customers telling them they would eventually have a white roof!

My business had provided a three sided “machine shed” 40 foot deep by 60 feet long and 10 foot eave to a farmer in the state of Washington. Within a year after he had the building up, he called because he had fist sized holes in the roof of his barn!

Well, there was a “Paul Harvey” to his story….he had enclosed the open side of the building, and then used it for raising hogs! The building had absolutely no ventilation provisions, nor was there a vapor barrier installed under the roof steel.

The wastes produced by the hogs contained a very high amount of ammonia, which reacted with the aluminum in the Zincalume®, and literally ate holes in it!

We recently had a client send us the photos seen with this article. Their four year old building had developed a series of rust through holes and the client wanted to know if the steel panels were still under warranty.

Strangely, the holes are all in a straight line, across one panel of steel and just onto the next panel. The line of holes just happens to coincide with the location of a “bookshelf” style wall girt on the inside of the building. Nowhere else on the building is there any sign of rust.

While the ultimate authority will be the steel roll forming company, my suspicion is some corrosive material was placed on the bookshelf girt (which was being used as a shelf), and it leaked or spilled along the girt line.

What came to mind first was an old battery. A frequent poster to internet discussion boards, from Tennessee, had this to say about battery acid and steel:

“I fought the battery acid contamination for years on mine equipment on metal a heck of a lot thicker…” “What I found is no amount of rinsing, or pressure washing will stop the damage from continuing and once the metal is contaminated replacement is about the best solution. The problem with acid is not just having the corrosive substance lying on the surface dissolving the metal, but the fact that once contaminated a chemical reaction is started that is very hard to stop! The acid will “eat” into the metal and cannot be simply rinsed off nor is it easy to neutralize for the same reason.”

Steel roofing and sidings are strong and affordable, however care must be taken to protect them from caustic situation, which may lead to premature failure of the product.