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Remodeling and Home Design
Monroe Closet & Home Storage Designers

Shed Foundations Made Easy

foundation for storage shed

The foundation of a storage shed is the first and most important part of installation process!

Building the right foundation for a storage shed is extremely important. The photo on the left shows a great example of what a poor foundation and time can do to a shed. Regardless of how strong the building construction is, if the shed foundation is poor it will not stand the test of time.

Consult your Local Building Inspector


Before beginning to build any foundation for your shed, consult your local building inspector to determine what type of foundation you will need. The decision will be based on the height and size of your storage shed. Regardless of the size of your shed, a building inspector needs to make sure that the storage building is up to code for your local area.

Click here to learn more about the process of obtaining a building permit for your storage building.

Does my Shed Need a Foundation?


Generally, smaller sheds of up to 8×6 do not need a foundation. Small sheds can be rested on crushed stone with either treated wood foundations or concrete foundation blocks. Large sheds will need to have strong foundations. Considering Backyard Buildings smallest shed size is 8×8, all of our sheds will need a foundation setup prior to the arrival of one of our installers.

*Backyard Buildings Minimum Foundation Requirements:

*Prior to the arrival of the installer, your site must be level within 6″h. * Additional charges may apply if this requirement is not met. *

Tools/ Materials Needed:



tape measure

Tape Measure

measuring chalk

Chalk Reel



concrete block foundation
Concrete blocks

Types of Foundations Used for Sheds

  1. Concrete slab foundations
  2. Wood foundations

Concrete Slab foundations:

concrete foundation for sheds

Concrete foundation shown here

We recommend our customers to use a concrete slab for their shed foundations. In preparation for the arrival of our professional installers, the build site must be properly leveled and should have natural drainage and no standing water. This will insure that your shed will remain strong and stable for many years to come.

Guidelines to Follow when Building Concrete Slabs (Not required, these are our recommendations)

  1. Your concrete slab should be the same width as the storage shed.
  2. The slab can be no greater than 1/4″ out of “square”.
  3. In certain markets that experience frequent hurricanes, 1/2″ x 8″ “J” type anchor bolts should be set in the concrete around the entire perimeter of the slab (except for the doorway) projecting approximately 2 1/2″ above the slab grade and approximately 1 1/2″ in from the edge.
  4. The finished slab surface needs to be at a minimum of 4″ above grade.

Wood Foundations:

Wood Foundation for shed installs

Wood foundations are typically built using solid concrete leveling blocks which are 8” x 16” and no more than 2” high. Each block is arranged in evenly spaced rows by placing one in each corner and at each break. These concrete leveling blocks will support the floor. If you choose not to use concrete leveling blocks, we recommend using pressure treated lumber to support the wooden floor frame.



Backyard Buildings suggested block count by sizes:

6X6 — 8

8X8 — 8

8X6 — 8

8X10 — 10

8X12 — 12

10X10 — 14

10X12 — 16

10X16 — 20

12X12 — 16

12X16 – 22

12X20 — 26

12X24 — 30

16X20 — 50 — *Piers or foundation may be required by state.

16X24 — 55 — *Piers or foundation may be required by state.

Don’t Forget the Frost Line…


Lastly, it’s important to consider the frost line of your region. If frost lines are not considered, your shed may move due to seasonal freeze and thaw changes. This means that the foundation will need to be built to the frost line. Once again, you will need to contact your local building inspector to determine the frost line for your area.

What Shed Foundation is Right for Me?


While there are other methods to building shed foundations, these are the two types we suggest to use. Choosing the right foundation for your storage building will make the entire process of installing a shed much easier and will allow your shed to stand up strong to the test of time! Once you build the foundation, we can do the rest!

If you have any general questions regarding foundations, please contact Backyard Buildings at 855-853-8558.

About bdeitsch

Loves to help others find the best solution to their backyard storage needs.
This entry was posted in Greenhouse Sheds, Shed Usage Tips, Sheds. Bookmark the permalink.
  1. Jennifer Haun says:

    Heya i’m for the primary time here. I came across this board and I in finding It really useful & it helped me out much. I hope to provide something back and help others like you helped me.

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  3. A. Piceno says:

    Hello,I plan to have compressed gravel as a foundation for an 8×10 shed. Is this wise?

  4. Paul M. says:

    What is your opinion on “Dek-Blocks”?

    • bdeitsch says:

      Hi Paul,

      I think it might depend on which type of deck blocks you’re talking about. If you’re referencing the deck blocks that you might find at Home Depot, they have one that can be used for 4×4’s. 4×4 fits in the plate. Some of the deck blocks are suited to 2x4s, not the 4×4’s our installers use for the foundations of our sheds. I hope that helps. Have a great day!

  5. Ken says:

    I am going to put a 7 x 7 or 8 x 8′ vinyl shed. The ground is out of level, and I have a TON of extra dirt (dug out a pool)
    Instead of digging to level the ground, can I build up the low spot with the extra dirt I have. (I am trying to get rid of it)

    • bdeitsch says:

      Hi Ken. Yes, that is fine. Besides the obvious, having a level shed foundation is important to prevent an abundant amount of sitting water. For example, if you have large holes underneath your building, puddles of water will form causing many different problems. Go ahead and use up as much dirt as needed… Have a great day!

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  7. Thomas says:

    I live in Florida and have sandy soil. Can I just level the ground for a 4×6 vinyl/resin shed and put the shed directly on the ground, or will I need to put down a bed of crushed shell, gravel, etc.?

    • bdeitsch says:

      It would be best to put gravel underneath the shed. If you place your shed directly on the ground, it may not allow excess moisture to evaporate. Please give us a call at 855.853.8558 if you have any further questions. Have a great day!

  8. Phil says:

    I’m planning to build a 12X20 shed and want to just use AB3 gravel for the floor inside the shed. The frost line here is 36″ and I don’t want to have to pour a concrete foundation. The area is fairly level. I was thinking about doing this:
    1. Set 4 CCA corner posts in concrete down to the frost line.
    2. Dig about an 8-10 inch trench around the perimeter, between the posts.
    3. Put about 6″ of leveled and tamped down AB3 gravel in the trench.
    4. Lay out 6X6 CCA timbers (2 high, between the posts) and drill through with rebar for stability.
    5. Backfill around the timbers with AB3, inside and out.
    6. Build the shed walls on top of the timbers and attach to the corner posts.
    Would this work?

  9. Rose says:


    We are preparing to put together our new 8X6 Resign shed on our concrete slab on the side of the house. The problem we are having is that the slab dips lower towards the center for drainage. How do we go about creating a level foundation? What type of foundation would be best and or easiest? This will be both our first times doing a project like this. Any suggestions will help.

    Thank you

  10. Ron says:

    I have plans for a 12 X 16 shed and plan on using 10inch poured concrete piers for a foundation. How many will I need if I use 2X8 rim joists and floor joists? I have sandy soil and no frost problems. How deep should they be set?

    Thanks for your help.

  11. Brandon says:

    Im going to build a 10 by 12 shed. I have a lot of cinder blocks will that be good enought to build on? If so what should I put over the level soil sand, rock and how deep do i put it on?

    • bdeitsch says:

      We don’t suggest that they use cinder blocks, but, a solid block would be acceptable, or they can use pressure treated 4 x 4’s for the foundation, crushed gravel. Feel free to give us a call if you have any further questions! Thanks.

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  13. Spauld says:

    I am considering purchasing a 16×24 Everest Tall Barn and using it as a workshop/additional living space to include a full bathroom. For this reason, I am planning to run utilities to the building including natural gas, water, sewer, etc. Since there is no way of knowing where the floor joists will be, there is no way to know where to locate the sewer line for proper flow (connection location) through a concrete slab. Therefore, I was hoping to have a standard footer with craw space installed and attached the Everest on top of it (just like a house). This way I could access the utilities by removing sections of the floor so I could run the sewer line (and other utilities) to exact areas of the building. Is it possible to have the building constructed/attached on top of this type of footer system?

    • bdeitsch says:

      Hi James,

      Thank you for visiting our blog. Can you tell me what city and state you live in? Based on that, I can give you the number for your closest servicing branch. One of our representatives may have to visit your build site for more background information. Feel free to give us a call at 855.853.8558 as well! Have a great day!

  14. Von says:

    I was going to have a 12×24 shed installer however the area is unlevel . The front would be on the ground but as you go back it would be in the air. Was wondering if I dig holes and intall post, would that work. If so how many and how big any other suggestions would help. Thanks so much.

    • bdeitsch says:

      Good Afternoon Von,

      Thank you for visiting our blog. Feel free to give us a call at 855.853.8558 and we can help you with this. Have a great day!


      Brennan Deitsch
      Online Customer Service

  15. Jill says:

    We plan to build an 8×10 resin shed on a foundation of small packed stone with a 2×4 boarder. Would this be ok?

    • bdeitsch says:

      Hi Jill,

      Thank you for visiting our blog. Yes, that should be fine. However, we do not work with resin sheds often, so I would recommend contacting the manufacturer as well. Good luck!
      Online Customer Service

  16. David says:

    I’m having a 10×12 garden shed delivered, it will sit on 4×4 Runners. I want a flat foundation underneath to keep rodents and animals from digging under . What’s the best and cheapest route to take for that. The shed will back up against a hill would that be a problem with drainage.? Thank you.

  17. Laurie says:

    My current shed has rotting seal plates that need replacing. I want to move the shed and place it on a foundation, what would be the best method.

    • bdeitsch says:

      Good Morning Laurie,

      Thank you for visiting our blog. You can start by reading our blog that covers this subject. . If you need any further assistance, feel free to give us a call at 855.853.8558. Have a great day!


      Brennan Deitsch
      Online Marketing Manager

  18. David says:


    I am planning to build a 20 X 16 shed in my yard in Brandon, FL. I want to be able to pull my truck in to work on it at times. I will be putting it on a Wood deck platform. What it the best ideas for weight support for the 5K Lb. truck? IE: 2X6s, 2X8s what type f spacing is best and which direction should the joists be going in reference to the roll up door? And help would be appreciated.

    • bdeitsch says:

      Good Morning David,

      Thank you for visiting our blog. Since we do not build sheds of that dimension and designed for that purpose, we unfortunately do not have any information to help you. Good luck with your build! Have a great day!


      Brennan Deitsch
      Online Marketing Manager

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  20. matt says:

    so, i used crushed stone as a base for my foundation. and although i had it tamped down and leveled, i am still having an incredibly hard time getting my 4×4 PT ties level. there is always a few rocks jutting up and making things difficult. and that is just one. next i’ll have to level the others with the first. any suggestions?

    also, for a 12×12 shed, lying on PT 2x4s (which will be on top of the PT railroad ties) how many 4×4’s would you suggest.

    • bdeitsch says:

      Hi Matt,
      Thanks for visiting our blog. You could get away with two 4×4’s, but we would suggest three. One for each side plus one support down the center.

      Our best suggestion for the leveling would be to use shims to help level it out. I added a link to our shed leveling document that shows this procedure. Hopefully this helps.

      Have a great day!


      Brennan Deitsch
      Online Marketing Manager
      Backyard Products

  21. matt says:

    thanks for the advice, however i can’t see the link.

  22. Romeo Paleracio says:

    I will have a wooden shed 8 x 8 installed in my backyard. I am planning to use
    4 x 4 treated lumbers as my foundation. Do you think 5 pcs of 4x4x8 will be enough to do the job?

    • bdeitsch says:

      Good Morning Romeo,

      Please give our customer service helpline a call at 855-853-8558. We can help answer your questions better over the phone. Have a great day!


      Brennan Deitsch
      Online Marketing Manager
      Backyard Buildings

  23. Ernie Valerio says:

    Im going to build a 10’x20′ foundation,would 3 pt 4x4s do the trick.
    Would I have to put them on 6″x8″x3″ solid blocks,with a gravel base? I’ve already checked with my building I don’t need a permit or anything else.

    • bdeitsch says:

      Hi Ernie,

      Thank you for visiting our blog. When we install we put them on 4×4 treated runners. You can put pavers under the runners if you choose. For more information on leveling and installing with the runners and pavers, please visit this link . As far as the gravel goes that is your preference on whether to put them down or not. Sounds like you have a good foundation! Feel free to give us a call if you have any other questions.

      Have a great day!


      Brennan Deitsch
      Online Marketing Manager

  24. Garrett Cox says:

    Good Afternoon,
    I’m planning to build a 10′ deep,12′ wide, and 14′ high barn style shed. about 5′ of the width is a porch. I’m concerned about underground power and gas lines, so concrete anchors are worrying me. Would 4×4 runners on dek-blocks be sufficient as a foundation?

    • bdeitsch says:

      Good Morning Garrett,

      This could work. Assuming your dek-blocks look like this. This could be accomplished by using 4 rows (on the 12’ side) of 3 (on the 10’ side). You would want to make sure that one of the rows is where the shed turns into the porch (almost treating them as separate entities/structures) for proper support. Forgive the crude drawing. Click here to see it
      Please let us know if you have any other questions. Have a great day!

  25. jeff says:

    I am building a 12×16 shed and i get alot of run in my area so i dont want to put it on a slab, what could work to build it on 4x4s?

    • bdeitsch says:

      Good Afternoon Jeff,

      Thank you for visiting our blog. Using a 4×4 foundation is our standard operating procedure, so this would not need any customization. If you have any other questions, feel free to give us a call at 855-853-8558. Have a great day!


      Brennan Deitsch
      Online Marketing Manager

  26. Ted says:

    We’re thinking of buying a vinyl/plastic shed and placing it on a pre-existing concrete boat pad next to our house. Any suggestions about this idea or pros/cons? Thanks for the very informative site.

  27. Steve Merritt says:

    I have small resin shed (3’x5′). Would a
    foundation of about 3-4 inches of pea
    gravel be sufficient? Thanks

  28. David says:

    I’m building a 10 X 12 gable shed and plan to use PT 2X8’s instead of PT 2X6’s for the floor along with either solid concrete blocks or deck blocks. Is the spacing of the blocks the same with both size joist? I would rather avoid using 4X4’s if possible.


  29. Dylan Miller says:

    im planning on buying a steel shed 12×24 and i need a foundation for it. we leveled the ground, and i was wondering if using just solid blocks would be ok

  30. NEIL says:


  31. Joe says:

    I am planning on putting a 10×10 shed directly on my wood deck. The deck is solid and there are no concerns about holding the weight. My question is, can I use the deck as the foundation, or do I need to lift it off the deck to allow for air flow? There are no spaces in deck. Thanks.

    • bdeitsch says:

      Good Morning Joe,

      Thank you for visiting our blog. We always recommend finding some way to allow air to flow under the shed. Especially if you live in an area that is humid and receives a lot of rainfall. Without air flow, water will often just sit there and soak into the wood. That is our suggestion. Feel free to give us a call if you have any other questions at 855.853.8558. Have a great day!

  32. Dolores says:

    Hello, i will purchase an 8’x10′ shed and use it as a play house for my two girls. However, we have built and elevated platform 5′ above ground. Is there anything a should pay particular attention to?

    • bdeitsch says:

      Good Morning Dolores,

      Just make sure there is enough air flow flowing under the platform. Want to keep away moisture and standing water. Good luck!

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