More in Remodeling
Before getting started, remove the cabinet doors, drawers and all hardware. Also remove the backing, bottom and any shelves from both cabinets.
Cut from the back. Use a circular saw with a finish blade to cut the excess depth from the back of the cabinets. Also cut away the excess depth from the bottom and any shelves.
Slide the bottom and any shelves back into place and re-attach the cabinet backing. Leave the drawers aside until later; they still need to be shortened.
Flip the cabinets upside down and measure the cabinet base. The height extension will consist of a plywood box the same size as the base. Use a circular saw to cut 1/2" birch plywood to the correct dimensions. Also cut slightly smaller pieces of plywood, which will be used to hold the extension in place.
Use wood glue and nails to attach the smaller pieces of plywood around the inside of the back and sides of the cabinet base. These pieces should extend above the base to provide a surface to glue and nail the extension.
Glue and nail the back and sides of the base extension in place, attaching to the plywood added in the previous step.
Remove the front of the original cabinet base and cut a piece of 3/4" plywood to cover the front of the extended base. Trace the desired shape for the drawer opening and make a plunge cut with a circular saw to begin cutting the hole. Complete the cut with a jigsaw.
Use wood glue and nails to attach the extension front. Use small brackets inside the extension to secure the front if needed.
Measure and cut 1" x 6" plywood to build a simple box to serve as a drawer to fit through the extension front. Install using standard drawer slides cut to fit the new drawer. Attach a handle or drawer pull to the front.
Remove the backs, bottoms and drawer slides from the drawers that came with the cabinet. Use a circular saw to cut the sides and bottoms of the drawers to the new size. Reassemble using wood glue and a nail gun. Replace the drawer slides on the drawers and inside the cabinet with shorter slides. Slide the drawers back into place.