What green risk is here to treat untreated wood to be used outside? Wood will be reclaimed from a 100 yr old home and planed...

Wood will be reclaimed from a 100 yr old home and planed down .

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Answers:    in attendance isnt a totally green option
if you use wood that isnt instinctively rot resistant it will of course rot, any preservative or coating worth putting on contains chemicals, insecticides, anti-mold etc agents
most woods that are essentially resistant are tropical
exceptions local oak, good resistance but expensive, elm honourable if kept wet, sporadic
what wood do you have

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Linseed grease?

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