Building a garage workbench against the wall will save space and maximize your floor area. You have to find the rules in the wall to attach. Build your workbench top from 3/4 inch cabinet plywood and add a 2-by-4-inch frame to support even the heaviest workloads. Locate your bench under a wall outlet for access to electricity. Paint or color your bench for a more beautiful look or leave it raw to save time and money.
Locate studs in your wall with a control detector. Place the locators flat against the wall and press the buttons on each side. Move locations along the wall. As it passes a stud, it will light up and peep. Select the location. Select all the studs where the free workbench plans will be placed. Cut 48 inches front, back and a support cleat, 21 inches for gables and between the braces and two oblique braces cut at 45 degrees at each end with the miters angled towards each other, with the long side of 30 inches. Cut a bench from 3/4 inch plywood to 24 by 48 inches.
Create a 24-by-48-inch rectangle from two 48-inches and two 21-inch 2-of-4s. Set two long two-by-4s parallel to each other 21 inches apart, standing on edge. Set a 21-inch 2-of-4 between and at even height with the ends of the parallel boards. Screw through the surfaces of the long pieces to the ends of the short pieces. Use two 3-inch treated tire screws in each joint. Place the remaining 21-inch piece in the center of the frame running parallel to the two 21-inch ends. It should be centered 24 inches from either end. Screw through 48-inch pieces at either end of 21-inch piece. Set the simple workbench top on the top of the frame and flush all four edges up. Screw through the top at the edges of 2-of-4 ram. Use 1 5/8 inch screws every 6 to 8 inches around the edge. This is your countertop.
Select a horizontal line between two studs 48 inches apart, 30 inches above the floor. There will be two studs between them. Use a level as a straight edge to mark the line. Place the remaining 48-inch 2-of-4 under this line and fasten with 3-inch screws in the guides along the line. This is your support barely. Place your worktop on top of the support button. Center it and drive screws into the two mitt studs through the back 2-of-4 on the frame countertop. Use two 3-inch treated tire screws in each stud. Drill holes through long slant support 2-of-4s. Drill two holes at each end, a 1-inch from the end and centered at the edge of the support, a 2 inches from the end.