Outdoor Concrete Ceiling and Pedestal Plate Outdoor Plates are designed to work with the OLC Outdoor Ceiling and Pedestal Mounts. The plates are built to withstand rain, humidity and ocean air, sun exposure and high winds. Having the plate separate from the column makes the system more manageable for lifting into place. The plate is fastened using 2 oversized holes, allowing the remaining holes to be used as a drilling template.