Comparison of Siding Materials for Storage Units - Natural wood is considered by many the most attractive siding for storage units. But wood exposed over time to water usually rots. Some woods, however, contain natural resins that make them relatively rot-resistant. Cedar is such a wood and very popular as a siding choice for storage units. But even cedar siding is not maintenance-free. Coat cedar with a UV-inhibiting sealer/preservative every other year to protect it from ultraviolet solar radiation. Apply a clear stain, as well, to help preserve its natural beauty.
Buying an outdoor storage building with a loft greatly increases storage capability, allowing you to store rarely used supplies overhead. For the exterior, build your own lean-to and attach it to the outdoor storage building to form a sheltered area for firewood.