Abstract: A hidden ventilating sill plate is fundamentally a new building product, installed along the top surface of the exterior perimeter foundation. It replaces the existing wood sill plate. The invention has a continuous set of air slot channels of a proscribed size perpendicular to the longitudinal axis, along its base, communicating natural air flow from the exterior to the interior of the crawlspace. The exterior side of the slot channels can open earthwards to allow the venting to be completely hidden from view, when the sill member extends out beyond the exterior face of the foundation and wall. The vent concealment feature also functions as a base to the siding and an integral drip edge. Insect mitigation is achieve by adding a mesh screen over the exterior exposed slotted openings. The preferred material for this invention is a plastic-fiber composite, allowing rot resistance, shear capabilities and, rapid extrusion or molding of the sill profile.