How to Build a Base for an Apron Sink

Measure the height of the sink with the tape measure from its base to the top of the sink that sits flush with the countertop. Add 1/2 inch and then mark this adjusted height onto the interior sides of the cabinet with a pencil.

Use the tape measure to measure both sides of the cabinet with the tape measure and cut a two-by-four plank with a circular saw to match the measurements.

Place a bead of construction adhesive on one 4-inch side of each plank and then press the planks onto the side of the cabinet interior, running horizontally from front to back across the width of the cabinet at the level of your penciled height mark. Make certain the boards are level by placing a carpenter’s level across the tops as you install them.

Secure the planks into place by driving a 1 5/8-inch square-drive deck screw through the side of the cabinet and into the plank every 6 inches using a drill with a screw set. The planks will serve as supports beneath the sink.

Measure the length and width of the space within the cabinet and cut a sheet of 1/2-inch plywood to match the measurement. Place the plywood across the two-by-four planks to help support the base of the sink. Check the existing plumbing in your cabinet. If the plumbing all runs to the rear, then shorten the depth of the plywood sheet to allow for placement without it pressing against the plumbing.

Add 5/8 inch to the measured height of the sink and then mark the front of the cabinet with a pencil at adjusted height. This will be the level of the cutout you must make to slide the sink into place. If the cabinet doors are above that level, then remove the hinges and take the doors off. You’ll need to replace them with smaller doors after the sink installation. Adding the additional height makes certain the front of your sink is not resting on the cabinet structure, and that the two-by-four support boards on the sides support the actual sink weight.

Measure the width of the sink, and then make a line matching the width at the marked height line that you made earlier on the front of the cabinet. Use a straightedge and a carpenter’s level to keep the width line level, and make certain the line is placed in the center of the cabinet. Use a carpenter’s square to make vertical lines from the ends of the width line extending straight up to the top of the cabinet, completing the cutting guides for your sink cutout.

Cut along the marked lines in the cabinet front with a jig saw, then remove the cutout piece. Sand the cut opening smooth with a piece of medium-grit sandpaper. With the cutout removed, you can slide the sink in place along the two-by-four planks.