Q: Some of the wood being used by the contractor framing our home addition has black mold on it. He says that this is okay. Do I need to be concerned?

A: It is not uncommon for wood framing lumbers during new construction to have mold discoloration (black or grey) on them. It is usually caused by being exposed to weather during construction. The affected pieces of wood with this discoloration should not be a problem, unless it is continually exposed to moisture for a long period of time. If that occurs then the wood itself may actually begin to deteriorate. If the wood has a chance to dry out before it is covered up by other construction materials, it should not be a problem in the future. However, if there are continued concerns, simply spraying the wood with a disinfectant or Clorox solution can be done, but only on the affected wood pieces.

Rick Anderson, P.E., Manager, EFI Global, Inc. Houston Environmental Office.

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If you have a question for a mold expert, please send it to Brett Lyon, senior editor of construction.com at brett_lyon@mcgraw-hill.com.