I'm building a Suncast Sutton storage shed.

I followed the instructions and built the wooden base as described. Based on many tutorials I've read online, I decided to use concrete blocks to level and support the wooden base.

Here are some of my questions:

  1. Am I using the correct concrete blocks? I've seen others use those square piers, will the ones I have work?
  2. Am I using enough blocks? Do I need any in the middle of the shed? As you can see I have a row in the front and in the back.
  3. Any ideas on how I can increase the aesthetics of the foundation? Specifically, those concrete blocks sticking out in the front don't look very good. Can I fill in with dirt?

Shed Base Sizing and Spacing

Shed Base

  • 1
    Your location will partly determine how intense you need to be with the foundation. If this is a permanent structure intended to last more than one winter you need to make sure the foundation goes below the frost line.
    – Hank
    Jul 7, 2014 at 15:51
  • 1
    I just built a foundation for a similarly sized composite shed. I used 9 4"x8"x16" concrete blocks with 2x6 framing around the perimeter and center, with 2x4 joists spanning 3.5' spaced at 12" oc. Your setup is probably OK if you're not planning on parking a riding mower in rhe shed. Otherwise I might consider at least adding a center support.
    – Doresoom
    Jul 8, 2014 at 1:59

2 Answers 2


Personally, I would dig the topsoil out from under the blocks—preferably down to mineral soil so that almost all of the concrete is buried. This makes less of a step up for wheeled equipment and less space for critters and weeds to grow underneath. I put mine very close to the ground on concrete blocks with slots for 2 inch wide lumber and concrete screws through the joist into the block to keep the wind from lifting it up:

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The kind of concrete block you are using is plenty strong, though I don't see anything to keep your shed from moving, for example from strong wind, heavy rain, or leaning livestock.

The strength of the joists is the next weakest link in this design. Some more support in the middle could be overkill, but it is unlikely to be so.


It costs more, but for longevity, I would use pressure treated (PT) lumber. If you want to be OCD about it, you should also treat (soak) all cut ends with wood preservative before assembly.

Not all pressure treated is intended for ground contact so make sure you get the right kind. You can typically find a label stapled on the end of the lumber. For ones touching dirt, it should say something like "ground contact".

I am in CA where termites thrive.

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