Does Linseed Oil Help Preserve Wood?
Linseed oil has several drawbacks, one of which is its slow drying time. It will remain tacky for days, possibly even months, depending on the weather and humidity. Another drawback is that it provides no ultraviolet light resistance, so decks will eventually turn gray. Furthermore, since it's a natural product, it will eventually biodegrade. You must recoat yearly — especially on wood in contact with the ground. Because of these drawbacks, modern wood preservatives are made with complex chemicals that eliminate the drawbacks but still keep the positive attributes of linseed oil.
