You can't have too many shelves. They are needed in virtually every room for supplies, crafts, souvenirs, keepsakes, toiletries or any number of household items. It's just not convenient to build shelves along each and every wall where and when you need them. Freestanding shelves are the answer. They are movable, simple to build and an effective way to get shelves where you need them, when you need them.
Freestanding shelf materials can be found at any home supply store. They include -- among others -- particleboard for economy, fir plywood for basic shelves, hardwood plywood for dressy shelves, and medium-density-laminate for clinical shelves. Particleboard is fine, but lacks the quality of plywood, and has a greater possibility of sagging with too much weight. Fir plywood is a good choice for sturdiness, and is a bit more costly than particleboard. It's a bit rough and requires sanding and either finishing or painting with a bit more labor included. Hardwood plywood is smooth, strong and attractive. Use it for electronic components, or things you want to put on display. It's the most expensive plywood and should also include stain and lacquer. Medium-density-laminate makes great shelves. It's strong and includes a plastic laminate on both sides to provide a slick, easy-to-clean surface. It costs less than hardwood plywood, and is one of the more commonly used shelf materials. All of these comparisons are based on 12-inch-wide shelves.
Freestanding units, although stable, should always be screwed to a wall for safety purposes due to the possibility that the shelf unit could tip forward. Even one screw keeps it from tipping. Start by cutting four pieces of 3/4-inch plywood of your choice according to your height and width to form the rectangular or square frame for the shelves. At this point you have a choice of either cutting dado channels for the shelves, or using glue blocks or cleats to support the shelves. If you decide on dados -- the recommended method -- install a 3/4-inch dado blade on a table saw and cut corresponding 3/8-inch-deep by 3/4-inch-wide channels perpendicular to the length of the shelf on both of the vertical pieces; this is where the ends of the shelves will slot into. The channel on both sides supports the ends of the shelves far better than screws or nails. If you're unsure about dadoing, or are not comfortable doing it, skip the dado cuts and screw sets of 3/4-by-3/4-inch cleats to the sides, using them to support the shelves.
Add some glue to the contact points, screw the pieces together at the top and bottom or use a nail gun, staple gun or even hammer the nails in by hand. Once the rough frame is complete, measure the distance between the two vertical sides and cut the horizontal shelves to fit. If you've chosen to use glue blocks or cleats, cut two pieces of 3/4-by-3/4-inch lumber for each shelf, and use a pin nailer to nail corresponding glue cleat supports to both vertical sides of the frame to support the shelves. If you've cut dado channels, measure inside the dados to get the shelf length, or add 3/4 inch to each shelf to compensate for the depth of the dado.
Cut the shelves according to your measurements for each type of support. Sand the shelves smooth using 100-grit sandpaper and slip them into the dados, or if you're using cleats, slip them in on top of the glue cleats. Nail the shelves to the cleats from the top, or if you're using dados, nail through the vertical sides into the ends of the shelves. For a stronger unit, it's highly advisable to cut a 1/4-inch plywood back. Add glue and pin nail the back onto the back side of the frame. This type of back adds an incredible amount of strength to the unit and keeps it square. Options other than full backs include partial backs such as a strip of 1/4-inch hardboard across the back to hold screws. Place a screw through the top into the wall, making sure to screw it into a stud for safety. Sand the unit and add stain and lacquer, varnish or paint. Build the units one at a time, or build identical units as needed and screw them together for even more support and strength.