Abstract: A building-construction panel includes a tongue on one edge and a groove on an opposite edge that receives the tongue of an adjacent panel. A shoulder on the tongue-side edge defines an abutted surface that is contacted by an abutting surface on the groove-side edge to limit panel travel during installation and maintain a gap between upper edge portions of the adjacent panels. A bottom transition is formed on the groove-side edge so that the groove-side abutting surface is smaller than the tongue-side shoulder abutted surface. In this way, the relatively smaller groove-side abutting surface structurally maintains the gap but also minimizes frictional interpanel contact area to minimize squeaking. And the relatively larger tongue-side shoulder abutted surface helps keep the shoulder from being collapsed into the groove from overdriving the panels together during installation. In typical embodiments, the panel is a high-performance structural wood subflooring panel.