Build a Platform for an Outside Storage Shed

Before you start building that storage shed you have been planning, you need to make sure to give proper attention to designing and building a good foundation.

How to Build a Platform for your Outside Storage Shed

Taking your time to design a solid foundation can prevent problems and headaches in the future and will be time well spent. Here are some details on how to build just the right platform for your outside storage shed.

Before you begin building your new shed, you want to find the right location to build on. Make sure the place you have chosen has solid level ground. Avoid any areas that are sandy or uneven. If you have to build in an uneven area, then dig out the area you will be building on to even out the ground. Make sure that you have solid ground to work with before you start.

Set your first two blocks 12 feet apart on the outside edges. Set your second set of blocks the same distance as the first, measuring 8 feet from your first row. Make sure you are measuring from the outside edges. This will give you the four corners of your project. Check for level by placing a 2-by-6-inch stud along the top of the blocks and placing your level on top of the stud. Do this for all four sides as well as checking diagonally.

Once you have the perimeter squared and level, place a pier block 6 feet on center from the outside edge of one of the existing blocks. Do the same for the other row of blocks. This will give you two exterior foundation lines. Place your remaining three blocks in the same layout, measuring 4 feet on center from the outside edge of your blocks. When this is completed, you will have three rows of three foundation blocks with an outside distance of 12 feet by 8 feet. Check all blocks for level and square with your original four blocks.

Place each of the 12-foot-by-4-inch-by-6-inch pressure-treated beams running on top of your piers, creating three foundation rows. Check for square and level, and then nail the beams to the metal straps on top of the concrete piers.

Lay the two 12-foot-by-2-inch-by-6-inch studs out next to each other and using a pencil, mark 13 3/4 inches from the end of each stud. Do the same for the opposite end of the studs. From the mark you just made, measure 1 foot 4 inches and mark that point on both joists. Continue measuring off 1 foot 4 inches from the previous mark and marking each point until you come to the end. These will be your center points for each of the 8-foot-by-2-inch-by-6-inch studs. Laying the studs out on the ground, begin nailing them together, starting with the end joist and two 12-foot rim joists. Be sure to nail the studs so that the rim joists are overlapping the end joist. When completed, you will have the framework for your shed's floor.

Move the framework onto the top of your foundation beams. Once you have it squared, nail the joists to the beams.

Take one of the sheets of 3/4-inch plywood and cut it in half so that you have two 4-by-4-foot pieces. Lay one of the 4-by-4-foot sheets on the corner of the framework across the floor joists. Using a full sheet of plywood, lay it on the end of the 4-by-4-foot piece so that you have covered half of the floor. Lay the other two pieces of plywood out on the studs in the opposite direction so that the 4-by-4-foot sheets are on opposite ends. Once you have done this, go ahead and nail the plywood to the studs.

Things You Will Need

  • 9 - 12-by-12-by12-inch concrete pier blocks with 4-inch metal strap 3 -12-foot-by-4-inch-by-6-inch pressure-treated beams 2 - 12-foot-by-2-inch-by-6-inch studs 10 -8-foot-by-2-inch-by-6-inch studs 3 - 4-foot-by-8-foot-by-3/4-inch plywood sheets Deck nails Hammer Level Square


  • To check for level on the diagonal, clamp a couple of 8-foot studs together to give you enough distance to reach the opposite concrete piers.


  • Always be careful to check for square and level before nailing the beams and studs.

About the Author

Carl Pruit has been a freelance writer since 2005, specializing in service journalism and travel. His work has appeared on various websites. Born and raised in California, Pruit attended Contra Costa Community College in San Pablo, Calif. and received an associate degree in the administration of justice.