Opportunities for extra storage abound in most every basement or garage. The spare is there, ready and waiting to be used, but how you use it can make a world of difference in both capacity and convenience, as this storage bank from the Better Homes and Gardens project series shows.

Capitalizing on every cubic inch of that space under the stairway, it holds almost anything you need to put away. You may need to alter the individual parts to fit the slope of your stair, but our steps tell you how to build the three basic components. Just fit them to the space available.

1. Work from left to right, beginning with the 20-inch-wide triangular piece at bottom of steps. Cut it to fit, and toenail in place.

2. Build the first and then the second of the roll-out, slant-topped bins. Make the front and back 12 inches wide and 1/2-inch shorter than the vertical measurement. Cut the tall side from perforated hardboard and shelves from 3/4-inch plywood, then assemble with butt joints. Recess the lower shelf to allow for the casters you buy. Add a 1x2 rubbing strip to the back of the tall side and the exposed edge of the top shelf so the bins roll easily.

3. Plan the width of the closet unit. Here, it's three feet, but it could be narrower. For the enclosure, cut the sides to the height that will fit under the stair, and add a back of 1/2-inch plywood, cut to fit. Complete the basic box by adding plywood for the "floor" supported with two 1x2s. Install a center divider if closet is more than two feet wide, and attach shelves. Nail a 1x2 to edge of each side to create a frame, cut doors to fit and hang with butt hinges.

4. Build the two vertical roll-outs like giant five-sided boxes. Those shown are 7 inches wide. Recess bottom and install platform casters, then add a 1/2-inch-thick rubbing strip to top and bottom.

MATERIALS: For this project, you'll need five sheets of 3/4-inch plywood, one sheet of 1/2-inch plywood, 12 linear feet of 1x2s, 16 casters, five hinges, and six large, heavy-duty handles.