A Custom-Built Vanity

2" x 4" lumber
3/4" particleboard
1" x 4" pine
1" x 6" pine
lag screws
construction adhesive
1-1/4" and 2-1/2" drywall screws
silicone caulk
finish nails
drill with pilot and spade bits
jigsaw

*Note: All measurements are for the featured project (replacing a stand-alone sink in a U-shaped wall area) and may need to be adjusted accordingly.

Steps:

1. Turn off the water, disconnect the plumbing (after the shut-off valves), and removed the old sink. Measure the distance between the walls on either side--this will be the width of the vanity top. Cut two 2x4s to that length for the front and rear frame, cut a 1x4 to that length for the backsplash, and a 1x6 to that length for the front skirt board. Next, cut two 1x4s to 23-1/4 inches for the side splashes and two 2x4s to 21 inches long for the side frame pieces. Draw a level pencil line around the walls at 34-1/2 inches off the floor so the completed height of the counter will be at a comfortable 36 inches when finished. Using a stud finder, mark the locations of the wall studs above the level pencil line.
2. Attach the sidepieces to the rear frame 2x4 using glue and a few 2-1/2" drywall screws. Place the assembly in the wall area, lining the top of the 2x4s with the pencil line drawn earlier. Drill pilot holes in the frame pieces and wallboard for the lag bolts as indicated by the locations of the wall studs. Attach the 2x4s with the lag bolts and tighten. Attach the front frame piece to the sidepieces with glue and 2-1/2" drywall screws. If necessary, have a lumberyard cut the particleboard to the length of the vanity top (the same length as the 2x4s cut earlier), but have them make the width (or depth of the vanity) 24 inches. Set the particleboard in place on the frame and check it for fit before attaching with construction adhesive.
3. Begin to make the top for the vanity by marking the center on the particleboard, and draw a line from the front to the rear. Cut lengths of 1" x 4" pine to 24 inches, and begin placing them on the particleboard, running front to back, until it's covered. Work with the pieces as needed to get them even and to determine how much will have to be cut off on either end to get the width needed. If desired, lightly round the edges over of each 1x4 for an even more rustic look. Be aware that this will make cleaning the vanity much more tedious. Once the size and shape of the 1x4s are determined, sand and stain the tops and sides of each, including the backsplash and side splashes.
4. Place 1x4s back in position on the particleboard. Work with one at a time. Remove a board, drill some pilot holes down through the particleboard (front and back), add a bead of construction adhesive on the particleboard, and then attach the 1x4 to the particleboard by screwing it in from the bottom using 1-1/4" drywall screws. Repeat steps for each piece.
5. Tape the template that came with the sink in place on the top. Drill a sizeable pilot hole, and then slowly and carefully cut the opening using a jigsaw. Check the fit, making any corrections to the vanity top, and remove the sink. Mark and drill two very small pilot holes for the centers of the faucet hardware. Since the stems on the chosen faucet are not long enough to go through both the particleboard and the 1x4 layer, drill up through only the particleboard with a large spade bit, and then drill down through the 1x4 layer with the spade bit called for by the faucet manufacturer.
6. Apply three coats of a water-based polyurethane to the entire surface, including the back and side splash pieces. When cured, run a bead of clear silicone caulk along the back edge of the vanity and set the backsplash into place. Tip it forward, and run a small bead of caulk along the back edge and place it back against the wall. Then apply similar beads of caulk along the sides of the vanity and attach the side splashes to the top and walls.
7. Paint the 1"x6" front skirt to give it a real rustic look with three different colors (a base, mid and top color). Sand through the painted surface in various locations to give the skirt boards a used and weathered look. Place the skirt board into position (even with the top of the vanity), and attach it to the frame with finish nails. Drop the sink into position and attach it according to the manufacturer's instructions. Finally, attach the faucet.

Note: If you choose to build the vanity base, the construction is similar as the vanity top with the exception that the particleboard layer is not needed. The 2"x4" frame members rest on the floor and can be attached to the wall with additional 2-1/2" drywall screws. The 1"x4" deck pieces can be attached to the frame with finish nails after being sanded and stained.