Trust the contractor or the engineer?

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Q. My architect’s engineer rejected my new foundation and wants testing done to check the (hand-mix) cement, which will hold work up for a month. I want to trust the engineer’s suspicion that the cement is weak, but the contractor says it’s fine. Also, the engineer didn’t see steel in the cement, and suspects it was done wrong. Whom should I trust? The contractor seems to know what he’s doing and has built a lot of homes around here without problems, but the engineer is telling me he’ll “wash his hands of this whole thing” and write a letter saying he rejects the work. What would you suggest we do?

A. I have two projects that failed testing after the owners heeded my professional advice. Both clients agreed that testing was necessary, and understood that we professionals have no ax to grind, nothing to gain, but are just doing our jobs. In one case, I saw masons mixing cement in a portable mixer as workers shoveled sand from a dump truck. This works for making grout, or “mud,” as some refer to it, to place under tiles, but that method has no structural controlled strength in a foundation.

A certified, documented, company “plant mix” should be stronger, but testing is still recommended by filling paper-reinforced tubes called cylinders. The cylinders are lab-tested at seven and 28 days to confirm the specified strength of 3,000 to 4,000 pounds per square inch. If not, well, we have a problem. The concrete foundation has to be removed, which is very expensive.

Your engineer has no other connection to your job, no other profit to make, with his advice, and you should take it. My clients had testing done and, in both cases, the cylinders failed. There’s not much to say about how reputable a person is when tests determine that the internal strength of the underground structure isn’t going to make it. Both clients are breathing a sigh of relief that they not only don’t have to wonder, but are in good hands. Fortunately, the contractors are cooperating, which isn’t always the case.

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