Expansion gaps are narrow distances that must be provided at the panel joints when fixing the straight-edge OSB boards on supports, in order to avoid dilation stress on the board edges. Expansion gaps allow the boards to expand unrestricted before reaching the equilibrium moisture, which is likely to happen if the panels are not conditioned to the end-use climate before being installed. Please consider the following factors:
- An expansion gap of 2-3mm provided between all adjoining boards when fixing to supports; the gap must be continuous on all 4 edges of each panel
- An expansion gap of 25mm left from the floor when fixing the boards to studwork, for wall sheathing
- A permanently elastic expansion gap of 10mm provided every 10m of continuous sheathing (roof, wall).