The limestone is a light-colored Indiana limestone. Some of the Manhattan Libraries contain a facade made entirely of this limestone. These libraries are accented with horizontal rustication. Some of the libraries contain bases and steps of marble, limestone or Maine granite. Nearly every Carnegie Library is made in the classical style of Beaux Arts, Classical or Renaissance Revival.
Large windows take up much of the facade and are set back from the face of the stone or brick.
This combined with the ornamentation, columns, pilasters, pediments, keystones, quoins, etc., increase the interest of the front with shadow. Stone trim is found around many doors and windows, the same stone can be found in the common pediments. Most of the libraries also contain a cornice, made of the original stone, or in some instances bent, sheet metal. The roofs were often covered with tar felt with gravel on the flat roofs. A few of the libraries also contained Spanish tile or metal roofing depending on the visibility of the roof and the weather that specific library would endure.