We want as much wood as possible to come directly from the property. We also want the structure to last a minimum of 200 years. Given those two criteria what do we do for the sill between the Durisol foundation of the house and the wood frame? In older construction this may have been a place for pressure treated lumber but since we could not find any pressure treated trees, the old arsenic treated pressure treatment of lumber was not only unfriendly to the environment, it is no longer made. There are newer products out that serve the function of keeping out the small crawly critters and wood rot. We chose a wood product that is treated with a product called Borate.
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"Borates offer low mammalian toxicity and effective protection against fungi and insects, including Formosan termites. They are colorless and odorless and can be easily infused into wood in aqueous solutions. Borate-treated wood is not corrosive to metal fasteners and accepts paint much better than copper-treated wood. For these reasons, borate treatments have become increasingly popular for uses where wood could be exposed to insects but not water, including sheathing and some dimensional lumber applications. Among the products currently on the market is the Advance Guard(tm) line of pressure-treated lumber and sheathing from Osmose. Unfortunately, borates remain water-soluble, causing treatments to rapidly lose effectiveness in exterior or ground-contact settings."