DIY Garage Shelves

Garage floors are usually concrete, and concrete can transfer moisture from the ground. Because of this, pressure-treated wood should be used for the parts of the shelf that touch the floor. Untreated wood will be used for the rest.

Moisture and stability are the reasons the bottom shelf on the unit will be just above the floor. 

Space the shelves so that the larger, heavier items can go on the bottom. 

This spacing will decrease as we go up for smaller, lighter items, and the top shelf will be wide open and flat. 

Tip: A thin piece of plastic can also be placed between the foot of the shelf and the floor if you choose not to use pressure treated wood.

Start this project by measuring the space for your custom shelves. This one will be 6 feet tall and 8 feet wide with three upright supports. 

Here are the pieces of cut lumber you will need to build these shelves:
 

• Six 2x4x72” PT
• Eighteen 2x4x24”
• Six 2x4x18”
• Six 2x4x16-3/8”
• Six 2x4x3” PT
• Plywood cut into two pieces, one 27x96” and one 21x96”
• 1x3 braces (these will be measured once in place)

Save the off-cut 2x4 pieces to be used as spacers during the assembly.

Tip: If storing heavy loads, or building longer shelf sections, additional upright supports can be added or the horizontal supports can be turned on edge and shelf slats doubled up.

• Place two of the 72-inch 2x4s on your work surface, on their edge and 24 inches apart.
• Lay four of the 24-inch pieces on edge between them, so it looks like a ladder.
• Start at one end and set the first rung 1 1/2–inches – the thickness of a 2x4 – from the end. 
• Attach it with two screws through the uprights.
• Next, attach two 2x4x3-inch pieces below the first rung, flat and flush with the sides and end of the upright. These will be the feet. Drill pilot holes in these small pieces to avoid splitting the wood.
• On each side, place a spacer above the rung, so it makes a 1 1/2-inch gap between the next pieces. 
• With one end against the spacer, place a 2x4x24” flat against each upright, flush with the edges. 
• Fasten the 2x4x24s” with 4 screws two from the outside and two from the inside.
• Then place the next rung directly on top of the interior supports and secure it with two screws through the uprights and into each end.
• Place the spacer on each rung again and install the next 18-inch interior support.
• Follow this procedure for all three upright supports with the 16-3/8” interior supports, and the top rung should be 1-1/2” from the end of the upright. Repeat this process to build a total of three.

Tip: Nails or screws can be used. Glue isn’t necessary but can be used if it you want. Fasteners should be rated for pressure treated lumber, regular screws or nails will corrode.

• Now, place four 2x4x8 studs on your work surface, with the ends flush. 
• Measure 48 inches to the center and lay a scrap of 2x4 across all four, using a square to make sure it’s straight.
• Stand the center upright up, with the 24-inch opening at the bottom, and place two of the marked 2x4s through it, above the bottom rung with the center marks facing outward.
• The 2x4s will slide into the gaps between the bottom of the internal supports and the top of the rungs.
• Align the centering marks with the outer edges of the upright and clamp them in place.
• Then, stand one of the end uprights at the end of these first 2x4 shelf slats and slide them into the gaps. Make sure they’re flush with the outer edges of the upright and clamp them in place.
• Repeat the process on the other side with the remaining upright and drive a screw through the face of the slat and into the rung at each joint.
• Remove the clamps and repeat the process across the top rung, there won’t be a gap, but the top of the 2x4 slats should be flush with the top ends of the uprights.

• Starting with the bottom shelf, lay three 2x4s across the bottom rung, spaced roughly 1 1/2 inches apart with the spacers on one end. 
• Drive one screw through each slat into the rung.
• On the other end, using the spacers, drive a screw through each slat and into the rung.
• Check for square and make any adjustments if necessary.
• Drive two more screws through all the slats on this end, then add two more screws to each slat at the other end. 
• Repeat this process with each shelf, from the bottom to the top.

Tip: Use a step ladder to work on the top shelf. Do not climb on the shelving unit itself.

• The next step is to add bracing to make this a solid piece of garage furniture.
• Place a 1x3x8 on the back of the unit, with one end on the lower outside corner.  
• Lean the upper end towards the center upright, until it overlaps enough to get two screws through it.
• Clamp the 1x3 in place and mark a line flush with the top shelf.
• Remove the 1x3 and cut it at the line. Clamp the 1x3 back in place and drive two screws at the bottom, into each shelf slat where they intersect, and finish at the top end.
• Repeat this process on the other side to make an “A” shape on the back the shelving unit. 
• The ends of the shelf are braced as well. 
• Clamp a 1x3 at the bottom rear corner and lean it towards the top front corner. 
• Mark and cut the angle at the top and then attach the side braces like the rear braces.

• The final step is to set the 27-inch wide sheet of plywood in place as the top shelf. 
• Align it with the four upright corners and secure it with three  1 1/4-inch screws into each rung.
• Then place the 21-inch wide sheet of plywood on the bottom shelf and fasten it with three screws into each rung.

Tip: Additional plywood sheets can be added to the center shelves, but they’re not needed if you’re storing items in bins or boxes.

If needed, have someone help move the shelves into position. With your new, custom garage shelves you’ll have a lot of storage space and be able to keep everything organized. A place for everything and everything in its place, the shelves will keep your garage looking tidy and help you access your tools and supplies easily, and there might even be enough room for your car.