Sized for Spacing on an APA Trademark
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.
APA usually recommends a 3mm (1/8-inch) space between panel edge and end joints and indicates this on its trademark by the words ‘Sized for Spacing’.
This tells the customer that the panel has been produced to a size slightly less than the traditional nominal 1220mm (48″) by 2440mm (96″). Standard panels tolerances are + or – 3mm (1/8”).
This is done to facilitate proper panel spacing and not to circumvent manufacturing tolerances. Click here for APA ‘s Technical Topic on the tolerances allowed by each US standard. Also, see examples of APA’s OSB trademarked panels.