Will the Attic Frame Support Storage?
If you’re thinking about using attic space for storage, it is rarely necessary to upgrade or reinforce the wood frame in order to make the attic suitable for storage. The ceiling for the highest floor level is framed with joists that are two inches by six inches minimum, and which are typically 16 inches on center. This is usually sufficient to support the loads imposed by the weight of the stored items.
Adding Attic Flooring
Not all attics have plywood decking installed onto the top of the ceiling joists. This will be necessary if the attic is to be used for storage. If full sheets of plywood will not fit easily through the attic access door, cut them into smaller, straight pieces. The sheets do not have to be nailed in completely—use just enough nails to keep them from sliding horizontally. Use plywood at least one half inch thick and be sure to nail through the plywood into the joists. The plywood decking will allow you to move around comfortably in the attic.