Wall shelves can be installed easily using metal standards and brackets. This hardware is readily available, inexpensive, strong, easy-to-install, and adaptable to a wide range of shelving options. Metal shelving standards and brackets can be used for bookcases, desks and other workspaces, media centers, and closet storage systems.
These systems work by means of metal standards attached vertically to the wall with screws driven into studs. Brackets are then be placed in the standards to extend out horizontally to support the shelves. Several types of standards and brackets are available; some are appropriate for light-duty use and others suitable for very heavy-duty uses. For most applications, the double-slotted, heavy-duty products are the best choice. You can usually find these in different finishes at big-box stores such as Home Depot or Lowe’s, at hardware stores, and from online retailers.
Standards and brackets are available in a wide range of sizes; the widest selection is offered through online suppliers.
Source: The Spruce