When you measure for your countertop be sure to include the counter overhang which is usually between 3 4 1 inch in front and on open ends.
Attach countertop to half wall.
Cut the boards 2 inches shorter than the depth of the countertop with a circular or table saw.
If you re working with bare plywood or particleboard place nails vertically down through the top of the countertop spaced about 4 inches.
Retape the strip in place.
Using a utility knife cut the cardboard along the scribe line.
If the holes are not completely lining up or you want a more secure install use wall anchors to attach the vanity to the wall.
If you attach a countertop to the wall with absolutely no cabinets whatsoever then use the same bracing techniques on both sides.
Check the level again before trimming the shims with a utility knife.
Make a mark 3 feet from the corner on one wall and 4 feet from the corner on the other wall.
Run the tip of the compass along the wall with the pencil on the cardboard to transfer the contours of the wall to the strip.
Slide the end of the countertop over the horizontal stud.
Screw the countertop to the cabinet sides using 1 1 2 in.
The fascia laminates and backsplash can now be added.
Attach the countertops to the cabinets.
Be sure to place pressure sticks along the back corners where the corner blocks are located to get the countertop down tight.
Attach the vanity to the wall using 3 inch drywall screws.
Push the strip back tight against the wall using the combination square to verify the overhang depth.
The point where two counters meet in a corner must be square.
Attach three 1 inch by 4 inch wood boards to the wall brace board to hold the countertop.
Reinstall the cabinet doors put the drawers back in place and go have a beer.