Particle board and plywood are composed of pieces of wood products that have been pressed and glued together. Although they are popular siding materials for storage units, they are not most people's first choice in regions where it rains a lot. For if water does work its way into these products (a possibility enhanced by their composite nature), then you're lost.
Before Installing Storage Units: Building Codes and the Like - Become acquainted with zoning ordinances, deed restrictions and building codes. Depending on your area, you may need a building permit. Building codes may determine how far storage units must set back from property lines and what materials are acceptable for siding.