I am making some slab, live edge outdoor tables and benches out of spruce for my cabin on the ocean in Washington state, i.e rain, rain, rain. I know that spruce rots easily, but I have a lot of it and it is free, so I'm looking for a good wood preservative for it. It's ok if it grays. The slabs are 2 1/2" thick.
I've looked at a product called Eco Wood Treatment, which is an eco-friendly preservative but not a repellant, or CWF, which is both a preservative and repellant.
Any advice?