Wheeler Lumber, LLC supplies copper naphthenate-treated ties and timbers from our treating facility in the Black Hills of South Dakota. We specialize in bridge timbers and pilings, beveled crossing timbers, timber structure design and timber fabrication including tapering, dapping, planing and drilling. Copper naphthenate (QNAP) is an AREMA-approved oil-borne preservative with proven efficacy. It has cleaner handling characteristics than traditional oil-borne wood preservatives with minimal leaching and drippage. For over a hundred years, Wheeler Lumber has been supplying high quality treated wood products to the railroad and heavy construction industries.