Using a utility knife cut the cardboard along the scribe line.
Attach countertop to half wall.
Steel angles with 5 8 in.
If you attach a countertop to the wall with absolutely no cabinets whatsoever then use the same bracing techniques on both sides.
If you re working with bare plywood or particleboard place nails vertically down through the top of the countertop spaced about 4 inches.
Push the strip back tight against the wall using the combination square to verify the overhang depth.
Retape the strip in place.
Slide the end of the countertop over the horizontal stud.
For a tight fit screw the angles to the cabinet first and then draw the top down to meet the steel angle with the second screw.
Attach the vanity to the wall using 3 inch drywall screws.
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.
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.
Check the level again before trimming the shims with a utility knife.
Attach the countertops to the cabinets.
Cut the boards 2 inches shorter than the depth of the countertop with a circular or table saw.
Make a mark 3 feet from the corner on one wall and 4 feet from the corner on the other wall.
Screw the countertop to the cabinet sides using 1 1 2 in.
Seal any gap between the backsplash and the wall or along the edges and the wall with a clear silicone acrylic caulk.
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.