If you want to build a shed in your backyard, you have to start with a shed floor. Building a shed floor is a job that can be done within a day or two. From beginning to end, it is a way to save money on your shed project. Making sure you have the right materials, instructions, and a friend to help if needed, you can have it done in no time! 

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Step 1: Check Town’s Construction Codes

Checking construction codes is an important step to do before beginning your shed floor. This will tell you what kind of anchoring your shed will need. You can anchor your shed in a couple of different ways. Those are by using cable tie-downs anchored to the ground or by fastening your floor to concrete posts that are put into holes dug in the ground. This choice could be dependent on things like the area weather or the size of your shed. 

Step 2: Prepare All Materials

You want to make sure you have everything you need ahead of time. Your shed floor materials include:

  • Pressure-treated lumber
  • Pressure-treated plywood
  • Joist hangers
  • Fasteners (framing nails and exterior grade screws)
  • Wood screws

Recommended tools to have on hand are: 

  • Level
  • Chalk line
  • Tape measure
  • Speed square
  • Circular saw
  • Nail gun
  • Palm nailer
  • Safety gloves
  • Safety glasses
  • Miter saw
  • Jigsaw 
  • Carpentry pencil

Step 3: Lay Out Deck Blocks

deck blocks layout for shed floor
Lay out deck blocks and level the area
  • Place your deck blocks down so they are equally distant apart from each other. There should be one about every 4 to 6 feet. This will help stabilize the whole floor. 
  • Lay 2x6s in the grooves of the deck blocks.
  • Tamp down and dig the ground. This will help make the ground level and give the floor frame good support. 

Step 4: Mark the Two-Band Boards

cut the joists for shed floor
Cut the necessary amount of joists

The amount of lumber you will need is determined by the size of your shed floor.

  • Prepare two joists and two rim joists according to the length and width of your shed. Pay attention that if the length of the rim joists is equal to the length of the shed, in order to calculate the length of the joists, you need to subtract the thickness of the front and rear rim joists from the shed width value.
  • Using a speed square, mark where your cuts need to be.
  • Cut your lumber according to your measurements using a miter saw, chop saw or circular saw if needed.
  • Make sure you seal the grain cut ends with a wood preservative. 

Double-check your measurements before you cut. This will save you from potentially making wrong cuts later, saving you time and money. 

Step 5: Put the Outer Frame Together

assembling the outer frame of shed floor
Assemble the outer frame joists and fasten them by using 3 nails

After you have finished your cuts for the shed floor, it’s time to put the outer frame together.

  • Nail the frame together by using 3” 16d framing nails.
  • Join every board together: one on the top, in the middle, and on the bottom for each.

When you are finished with these four, you should have formed a box. 

Step 6: Square the Floor Frame

square shed floor frame
Square shed floor frame by equal distances
  • Measure diagonally from one corner to another using a tape measure.
  • Do this for both sets of corners.
  • Make sure the measurements are equal. If it isn’t, hammer the longer corner a bit. Sometimes, a shift deck block may be necessary.
  • Keep adjusting until the measurements square up. 

Step 7: Anchor Floor Frame

shed floor anchoring
Anchor your shed on concrete piers

After you have determined the location of all the blocks, you need to prepare the foundation for fixing the frame. It is probably best to anchor your shed with concrete piers.

  • With spray paint, mark under each corner where you want your anchors to be. Depending on the size of your shed, you should only need one in each of the corners.
  • Dig holes on your 4 marks.
  • Install the fiber-form tubes into the hole so that the top edge is 4 inches above the ground.
  • Level this off and then fill each hole with concrete.
  • When the concrete is cured, install a bracket on the inside of the frame and fix it with an anchor to the foundation.
  • Repeat the procedure for all prepared foundations.

shed floor anchoring diagram

Step 8: Add Rim Joists

install rim joists to shed floor frame
Place the rim joists inside the floor frame
  • Cut these joists the same as above using the speed square. This is where having a square frame is particularly helpful.
  • After all of these are cut, place them inside the frame. They should all sit 12”-16” in the center.
  • Calculate the step between the rim joists as a multiple of the sheet width and, if necessary, move them under the joint of the sheets.
  • Mark the increments along the length of the frame on both sides. Where the center of each joist will go is what needs to be marked. 
  • Attach joist hangers using Simpson screws to the frame. You have to make sure the joists are flush with the top of the frame. 
  • Put the joists into the hangers. If it’s a little tough, use a hammer to tap them down.
  • Use 3” nails to attach the hangers to the joists. These nails should go in on an angle so they can go through the joist and the frame. For larger sheds, it’s a good idea to have a middle support beam that runs perpendicular to your joists.
  • Cut 2×6 blocks and insert them at 4’ and 8’ distances from the outside of your frame to prevent them from twisting. This will also provide extra support for the edge of your plywood for your shed floor. 

Step 9: Lay Out the Sheeting

plywood layout for the floor
Lay out the plywood on the shed floor frame
  • Cut your plywood to the length and width you need for your shed floor frame.
  • Lay it down and make sure it’s even before you start screwing it down. It will help if you snap a chalk line where the joists are. This will make it easier when you need to screw into the joists. 
  • For uniformity and stability, place the screws about 8” apart. Where two pieces of the wood meet, use two screws on each piece of plywood. These won’t back out of the wood. They also help keep the floor from squeaking and getting bumps.


Making your shed floor can be a fun and fairly simple way for you to save some money. Make sure you are double-checking yourself (especially measurements) so you don’t have to go back and correct something down the road. A well-built shed floor will last for a long time and now it’s time to learn everything about wall framing. It’s not that difficult and it won’t be long and you’ll have a beautiful shed that fits your needs.


Joseph TruiniJoseph Truini is a host on the Today’s Homeowner TV show and co-hosts the weekly Today’s Homeowner Radio Show. He has written three best-selling shed-building books and lives in Roxbury, Connecticut.