Ask the Architect

How bad is a rusted beam?


Q. We don’t live near the ocean, but a recent engineer’s report, for the people who were going to buy our house, said our support beam was rusted. He didn’t recommend that it be changed, from what we know, but it scared them off. We looked at it, and even though it is rusted, it doesn’t look any different than our next-door neighbor’s, who tells us that everyone’s beams are rusted. So we looked around our neighborhood, and they’re all rusted. Should we be concerned? When is a beam too rusty, and is there anything we can do about it now? Also, if we have to replace it, should a new one be “galvanized,” as the engineer wrote in his report?

A. This question reminds of a commercial laundry I had to investigate. We were converting the building into a retail store, in a very expensive neighborhood. The laundry signs boasted “state-of-the-art” cleaning techniques. Fine silk and leather were cleaned there as well.

The laundry business was still running when I walked between the plastic bags and motorized racks on my way to the back stairs. Out of nowhere, a hand reached out from between the hanging plastic-wrapped clothes, holding a paper mask. I nodded, took the mask and descended into the basement, where the dim exposed light bulbs revealed an almost medieval scene I was not expecting. Thin young men, presumably speaking no English, with cloth rags across their faces, were moving vats of chemicals on broken concrete floors with old wooden dollies in preparation for the business’s closing.

Above me was the beam and floor system I was to examine. The beam was so rusted that when I touched it, the scale not only fell away, but I could stick a finger right through the beam to the other side. I realized right away that the chemicals used in the dry-cleaning operation were so corrosive that the exposed beam had badly corroded, confirmed by research and interviews with laundry experts. The same question you asked was posed in this more extreme circumstance.

That beam was so bad that it could have failed, yet it didn’t, and the building owner refused to replace it unless it could be shown that it was required. The beam was tested with sounding devices and radiological testing, which were expensive, yet less than the replacement would have been, and they determined that the rusted-through beam was “adequate, though recommended to be replaced.”

It never fails to surprise me how indifferent and dismissive people — like your buyers — can be about learning the truth, but in the interest of time and money, they moved on. The engineer’s commentary leads to avoiding responsibility, because testing is expensive. Without further testing, only rust-preventive coatings can be applied, if the beam is sound enough to keep. Next week I’ll discuss what you can do.

© 2017 Monte Leeper. Readers are encouraged to send questions to, with “Herald question” in the subject line, or to Herald Homes, 2 Endo Blvd., Garden City, NY 11530, Attn: Monte Leeper, architect.