The American Plywood Association (APA) recently shared this interesting video concerning the proper spacing of plywood and OSB panels. In the video they demonstrate how much a panel can buckle when there isn’t proper spacing between the panels.
“APA recommends a 1/8-inch space between panel edge and end joints. Plywood and oriented strand board (OSB), like all wood products, will expand or shrink slightly with changes in moisture content. If the wood structural panels are tightly butted, there is no room for expansion and buckling can occur. That can mean costly, time-consuming callbacks.” — from http://www.apawood.org/buildertips/pages/M300.html
In the video they mention that when a panel buckles, the siding materials, roof shingles or floor coverings buckle with it. When we think about this with stucco applications, we can understand why stucco would crack with the slightest seasonal movement when the wood underneath is butted tightly together. “So make sure when you are working with plywood or OSB to space all joints 1/8″.”