Q.: We have had bad experience repairing the second floor of an industrial warehouse. We used epoxies to repair extensive spalled and broken areas, but the repair didn't last. Then we patched with concrete, mostly in areas about 1 or 2 feet wide and 2 feet long, though one area was 12 by 20 feet.
We used what we believed to be established, reliable techniques, but the floor is again spalling near a truck entrance where traffic runs over it continually. What should we do next?
A.: We suggest you have a consulting engineer look at this floor.
Note: Subsequently the floor was investigated by a consultant who found that the base, below the patch, was badly cracked, causing excessive deflections when forklift trucks ran over it. The engineer was convinced that the cracking in the base was getting worse. He recommended installing a large, stiff beam under the cracked section of the floor before installing new patches.