Although the Warehouse type has been around since the mid-19th century, major innovations were not made until the first decade of the 20th century. These large, multiple-story structures typically feature a ground-level office area that usually occupies only a portion of the floor, with the rest of the building being open floor space devoted to storage and manufacturing.
The buildings are primarily utilitarian in design and might have basic stylistic embellishment on the street level or just at the main entrance. Early examples featured heavy timber framing as the primary structural support. The thick timbers allowed for a slower burn time in case of fire, to which these buildings were prone.
In the early 20th century, iron, steel, and reinforced concrete replaced timber as the main structural components. There are usually several large windows located around the exterior of the warehouse along with rooftop light monitors to allow as much light as possible inside the open spaces.
Water towers for fire suppression systems and elevator and stair towers that project above the roofline are other common features. On the main level, usually at the rear or sides, are located loading docks and bays for trucks and freight trains (for those located on railroad spurs).
Warehouses are usually, but not always, grouped in industrial areas on the outskirts of cities where the rail lines or roadways provided easy accessibility.