A.Paul Fisette, director of Building Materials and Wood Technology at the University of Massachusetts Amherst and a JLC contributing editor, responds: While borate-treated lumber isn't rated for continuous exposure in wet conditions, it is fine to use it for framing that eventually will be closed up and protected from the elements.

Where there is direct long-term contact with the soil or water, borates can leach out over time, but SBX lumber that's on a dry concrete foundation and covered by sheathing and siding should remain stable. It won't be significantly affected by exposure to the elements during the construction process, either.

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