aspect of the invention a layer of resilient deformable material 40 is positioned under the sheet 16 along at least a portion of the edge surfaces 22 and 24 the material is preferably secured to the core by a conventional adhesive and partially compressed by the sheet 16 which is wrapped over it the partial compression is best achieved by pulling the sheet 16 under tension as described below prior to securing the extreme edges 30 material 40 is preferably a compressible foamed plastic or elastomer such as polyvinyl chloride polyester polyurethane polyether polyethylene polychlorobutadiene polyacrylate natural rubber styrene butadiene copolymers and ethylene propylene copolymers in addition it may also be formed from non foamed elastomers or even a felt or corrugated paper in any event the panel edge prior to assembly with other panels into a wall must have a residual compressibility or resiliency permitting the edge to be compressed at least about 10 mils in a direction perpendicular to edge surface 22 and 24 when a pressure of at least about 0 01 lbs per lineal inch is applied such further compressibility permits two panels to be abutted readily edge to edge so that the sheets 16 thereof are in contiguous and intimate contact along the entire edge portions of the panels leaving.