Q.I was wondering what should be done to old reclaimed barnwood before it can be used inside a home. I plan on using it for wainscot in a basement remodel; should it be treated to kill any bugs or mold?
A.Contributing editor Paul Fisette responds: You could apply chemicals that would be toxic to any wood-destroying organisms and mold that might be present, but there are safer alternatives.
To me, the most appealing is to find a local sawmill that has a dry kiln and have the barnboards kiln-dried at 160F for 24 hours to kill any insects that might be living in the wood. This should work well with most barnboards, which are typically only 3/4 inch thick. As for mold, it needs moisture to live; since the kiln will dry the boards, the process will deactivate any mold spores on the boards. If there are obvious blooms of mold on the surface, use a stiff brush and a mixture of detergent and water to remove them, then let the boards dry before installing them. While chlorine bleach is often recommended for killing mold, it shouldn't be used routinely because it's toxic and may dramatically change the color of the boards.
There are other organic mold treatments on the market that claim to be environmentally friendly, but keep in mind that any surface treatment (including bleach) will not necessarily penetrate deeply enough into the porous structure of the wood to reach all fungal growth. If you decide to apply any of these treatments, be sure to experiment with sample pieces to see whether it will change the appearance of the wood. The key is to dry the wood and keep it that way, making sure the basement will be kept at a relative humidity below 60 percent.