TopNotch is LP’s drainable subflooring line. It features a self-spacing tongue-and-groove profile for easy installation, as well as a notch system that helps protect against moisture absorption and edge swell by draining rainwater away during construction. The line includes one commodity grade and two higher grades; the latter two come with 100- and 200-day no-sand warranties. LP says that it sources wood for the OSB through programs certified under the Sustainable Forestry Initiative. Sheets are priced around $31 apiece.