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Creating the Right Foundation for Your Storage Shed

One of the first things you need to determine before assembling your storage shed is what type of foundation you plan to use for your shed. No matter what foundation you use, it is essential that you pay close attention to the manufacturer's specifications regarding foundation types. Most manufacturers recommend a concrete pad foundation or a wood platform foundation as the best options. There are several reasons why these two choices are the best. A level concrete foundation is best because it creates a solid long-term solution and a very stable base for the structure, ensuring that the building is square and will not encounter any buckling or twisting under its own weight creating potential problems with the structure in general and with things like the doors closing properly. Wood platform foundations can also be a very solid and level solution, but it is important that you use treated wood. There are cases when even treated wood over time can experience problems with rot and need to be replaced. These instances seem to be rare, but the possibility does exist making the concrete foundation a superior choice. Below are a few general guidelines to consider when installing either type of base.

When constructing your foundation it is best to consult a professional and/or follow the specifications of the concrete manufacturer. The following will provide a general guideline when constructing a concrete base for a storage shed.


Concrete Slab Foundation

The slab should be at least 3" to 4" (8-10cm) thick. It must be level and flat to provide good support for the frame.

The following are the recommended materials for your foundation.

  • 1 x 4's (2,5cm x 10cm) (will be removed once the concrete cures)
  • Concrete
  • Sheet of 6 mil plastic
  • We recommend for a proper strength concrete to use a mix of:
    • 1 part cement
    • 3 parts pea sized gravel
    • 2 1/2 parts clean sand
Prepare the Site/Construct a Foundation
  1. Dig a square, 6" (15cm) deep into the ground (remove grass).
  2. Fill up to 4" (10cm) in the square with gravel and tamp firm.
  3. Cover gravel with a sheet of 6 mil plastic.
  4. Construct a wood frame using four planks of 1x4 (2,5cm x 10cm) lumber.
  5. Pour in concrete to fill in the hole and the frame giving a total of 4" (8-10cm) thick concrete. Be sure surface is level.
Allow 3 - 5 hours for construction and a week for concrete curing time.


Wood Platform Foundation (Example is for a 10x12 Shed)

If you decide to build your own foundation, be sure to select the appropriate materials. These are the recommended materials for your foundation:

  • 2 x 4's (5cm x 10cm) Pressure Treated Lumber
  • 5/8" (1,5cm) 4 x 8 (122cm x 244cm) Plywood-exterior grade
  • 10 & 4 penny Galvanized Nails
  • Concrete Blocks (optional)
Wood Foundation Diagram

The platform should be level and flat (free of bumps, ridges etc.) to provide good support for the building. The necessary materials may be obtained from your local lumber yard.

To construct the foundation follow instructions and diagram. Construct frame (using 10 penny galvanized nails) Measure 16"/24" (40,6cm/61cm) sections to construct inside frame (see diagram)

Secure plywood to frame (using 4 penny galvanized nails)

Allow 6 - 7 hours for construction.

Some consumers use patio blocks to create a foundation and this can also be an acceptable choice as long as the foundation is carefully planned out and executed in a manner to create a solid, level base for the shed. We do not have any recommendations at this time for this type of base and recommend consulting a professional.

*This article was written by Storage Sheds Outlet and is a general guideline to follow when creating a foundation. Storage Sheds Outlet gives no guarantee that these guidelines will result in a perfect foundation, free of problems and recommends that consumers consult a professional before planning and building any foundation for a storage shed.