Abstract: The present disclosure relates generally to building surface systems, for example, suitable for forming an internal or external surface of a building. The present disclosure relates more particularly to a building surface product that includes a panel and a first attachment post extending outward from a rear surface of the panel. The first attachment post includes a shaft having a first end that penetrates the rear surface of the panel and second end that is spaced from the panel. The first attachment post also includes a lip extending radially outward from the shaft that is configured to hold the first attachment post in an aperture of a support structure. The disclosure also relates to a building surface system including a plurality of rails configured to panels that include an attachment post.