A. Bill Palmer, president of Complete Construction Consultants in Lyons, Colo., responds: It’s best not to use forming lumber and plywood for anything but forming. Even though the IRC doesn’t prohibit it, reusing form boards for other purposes — except perhaps in noncritical locations, such as for blocking — isn’t a good idea. Many of the reactions that degrade lumber naturally occur more quickly when it’s exposed to concrete. Adding to the problem, many of today’s concrete mixes have a very high pH and alkalinity that will burn off the surface layer of any wood they are poured against.
Simply cleaning the lumber isn’t a reliable solution, either, because you may not remove enough of these corrosive chemicals to prevent long-term deterioration — and the act of stripping the wood form may cause damage that isn’t apparent until the wood is put under load. For example, if 2x12s used to form a slab are later used in load situations...
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