Although shelves are often the result of upcycling larger pieces of furniture and scrap materials, sometimes it's the shelves themselves that need a new life. Wooden shelves are the most versatile to repurpose, especially if you have carpentry skills good enough to build benches, end tables or picture frames, but even wire shelves and large built-in units can be reconfigured.
Free-standing Shelf Units
A typical bookshelf is a sturdy piece of furniture no matter which way you turn it. Place a large shelf unit face down on the floor to support a mattress for an instant platform bed or futon base. A wide-enough bookshelf can also serve as a headboard. Simply push the mattress in front and continue to use the exposed shelves, or turn the bookshelf to face the wall and paint or upholster the solid back of the unit.
A more creative option is to turn a wide, deep shelving unit on its side to create narrow spaces that can be used as personal lockers for kids. Add legs to raise the unit to the necessary height, paint the interiors with brightly colored enamels and add a coat hook at the top of each space and a basket at the bottom.
Bracket-Supported Shelves
Probably the simplest way to repurpose single shelves is to reuse the boards for other wood projects, while using the shelf brackets as anchors for hanging plants. However, you can also upholster a shelf placed below a windowsill to make a comfortable basking area for an indoor cat. Or you can cut large holes in a shelf, paint it with exterior enamel and rehang it outside the window to hold potted plants.
Built-in Shelves
When shelves are part of the home architecture, repurposing is necessarily on a larger scale. Removing the shelves to leave only the recessed area makes that space available for conversion to any number of hide-away options. Build in a pull-down bed for extra sleeping space for guests; use it to build in a sewing center with a fold-away ironing board and sewing machine table; or make a built-in hobby or entertainment center in much the same way. Hang folding or sliding doors in front to hide the contents when they're not in use. Use repurposed shelves to build in a low window seat below wall-mounted lamps for a cozy reading nook as another possibility.
Wire Shelves
Wire shelves can become junk when you get rid of the things once organized. Fasten a small wire shelf unit flat against a ceiling to make a hanger for pots and pans or tools -- use “S” hooks to hang items from the unit. Fit small individual shelves with short legs to serve as countertop cooling racks for baked goods; dismantle larger units with wire cutters and use the sections to make tiny pet ladders, tie or necklace hangers, small plant trellises or ribbon and trim holders in the craft room.