How to build a 12 FT x 12 FT shed

Updated July 20, 2017

If you lack storage space in your home or at work and need a place to store household items, tools, or odds and ends, a great solution for this problem is a simple wood shed. All that is required to build one are a few basic tools, four types of lumber and hardware.

Prepare the ground the shed will be built on. Most importantly, the area must be solid ground so there will be firm support for the base. Also, reasonably level ground is recommended because it is easiest to work with. Level the area using wood or brick support posts if there is a variation in height.

Cut the 6-by-8s for the base of your shed. Leave two pieces at 12 feet long and cut six 8-foot-long pieces.

Cut four 6-foot square pieces from the four sheets of 3/4-inch plywood for the floor.

Pressure treat the eight 6-by-8s and the four 6-foot square pieces of 3/4-inch plywood for the base to prevent rot. Also pressure treat 41 12-foot 2x4s.

Use penny nails and assemble the frame for the floor on top of the levelled area. Nail two of the 11-foot 6x8s between the two 12-foot 6x8s pieces forming a square. Equally space the four remaining 11-foot long pieces inside the frame parallel to the 12-foot pieces for floor support. Attach them to the 11-foot outer sides of the frame with penny nails.

Lay all 41 12-foot 2x4s across the top of the frame perpendicular to the support beams for extra strength under the floor. Drive 2 1/2-inch screws through the 2x4 boards where they come in contact with the frame.

Construct the 12-foot by 12-foot floor by laying the four 6-foot square pieces of 3/4-inch plywood over the 2x4s. Nail them down to the 2x4s.

The walls need to be at least 7 feet tall for head room. Determine which side of the shed you want the door on. Allow for a 3-foot wide by 7-foot high opening for your door and include in your frame plans. Use two 2x4s side by side on both sides and along the top of the door.

Assemble a 12x7 foot rectangle using of 2x4s and nail it together to make a frame for the 12-foot wall. This includes two 12-foot pieces and two 6-foot 9-inch pieces.

Next, cut 6-foot 9-inch pieces of 2x4 for the vertical studs between the top and bottom pieces and space them 8 inches apart. Build the other two 12-foot walls 11-foot 5-inches long to fit between the walls built in Step 9.

Stand all four walls up and nail them together. Nail them to the plywood base every 6 inches and to each other every 4 inches.

The slope of the roof should run perpendicular to the wall the door is on. Nail a 12-foot 2x4 on edge across the top of the shed running in the centre of the two walls. The purpose of this piece is providing slope for the roof.

Build the roof by first cutting appropriate-sized sheets of 1/2-inch plywood to cover each side. Nail them from the frame up to the 2-by-4 forming an A-frame.

Cover the outside of all four shed walls with 1/2" plywood and brush with waterproof sealant. Cover the floor and roof with sealant, too.

Add protection to the roof. Cut pieces of tin to fit and nail to both sides of the roof.

Use lightweight plastic doors cut to fit the doorway or cut your own using plywood. Hang your doors with heavy-duty hinges.


Be cautious when using power tools.

Things You'll Need

  • 8 12-foot-long 6-by-8s
  • 60 to 70 12-foot-long 2-by-4s
  • 4 4-foot by 8-foot sheets of 3/4" durable plywood
  • Measuring tape
  • Circular saw
  • Pressure treatment liquid
  • Hammer
  • Nails
  • 4-foot by 8-foot sheets of 1/2" plywood
  • Water sealant
  • Tin sheets
  • Hinges
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