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Block Shed Foundation - Building

How to Build a Block Foundation for a Shed


Block Foundations for Sheds

Here at Byler Barns we have had great success using cinder blocks to build a block foundation for our portable sheds. These block foundations are quick, inexpensive, and far more reliable than simply setting a building on bare dirt.

Block Shed Foundation - Building

Decision time: Is a Block Shed Foundation Right For You?

An above-grade block foundation isn’t right for every building. Let’s take a look at when a block shed foundation works.


  • Building a shed under 14×24 (approximately)
  • Your shed has pressure-treated 4×4 skids underneath the floor, designed to sit on blocks
  • If you are not storing a vehicle or farm tractor
  • Your building site is not wildly sloped


  • Building a large shed (our max building size for block sets is about 250 sq. feet)
  • Storing vehicles or farm implements
  • Building on the side of a hill


Block Shed Foundation - pushing it
This isn’t exactly a hill, but it’s pushing the limits of a block shed foundation. In a case like this, measure the slope before you begin to make sure you don’t end up with a floating (and then collapsing) shed.

Have you decided to try it? Here’s the step-by-step guide to building your own block shed foundation.

1. Choose Your Location

Consider shed use. Choosing the location of your new storage building is key. What will you use your shed for? If it will be used for garden supplies then make sure it’s not too far from your gardens. If you will be accessing it regularly, you might want it closer to the house than if you plan to make a few annual Christmas decorations pilgrimages. Last week I delivered a building for a man that kept the shed at the end of the driveway, about 200 yards from the house. He said he plans to build a chicken pen off one end of the building and hoped to keep the smell far away!

Consider terrain. The terrain will also play a big part for your location. Generally, the flatter the better! Once the blocks are all set and the building is in place it should be sitting perfectly level. If the ground is sloped, one end of your shed will be sitting higher on blocks than the other.

Pro Tip! It’s helpful to envision the appearance of the finished product: one side being high off the ground might not be a deal breaker if it’s the side that isn’t seen from the road or the house.

Pro Tip! It is also good to consider how water will flow in the event of heavy rain. Don’t be like the foolish man who build his house on the sand, when the rain comes down and the floods come up you want your storage shed to stand firm! (Fortunately Byler Barns are built to incredibly high specs and can withstand most of what Mother Nature throws at us, but all the same, the sight of your building floating down stream isn’t something we wish for you to experience.)

Consider a few other things …

  • Overhead Trees. Shingle roofs enjoy the longest life when leaves aren’t collecting to rot.
  • Property Line. Most places in Virginia you should be no less than 5 feet from your property line. Check with you local zoning agency for specifics.
  • Delivery Access. Oh yes, and be sure that if you are getting your shed delivered, the delivery truck can access the place you plan the building to go. Talk to your sales people if you are unsure about this.


2. Get Ready

Before you launch, you will need to round up some tools and materials.


  • Tape measure
  • Writing instrument (Sharpie, pencil, or … a pointed rock)
  • Digging tools. A mattock works very well, and is what our delivery guys primarily use. A shovel may help you as well.
  • Carpentry level. The short, bullet levels work really well. 2 foot levels are good too.


  • 2 long, straight 2×4’s. These need to be at least as long (and wide) as your building is long (and wide).
  • Blocks. Don’t use hollow cement blocks, as these will eventually crumble. Use solid 8″x16″ block instead. Some of our block sizes are a little specialized, so you may need to go to a masonry supply store to find them. We have three different thicknesses:
    • 1-5/8″
    • 2-1/4″
    • 3-5/8″


Block Shed Foundation
Various thicknesses of blocks make it easier to level the block piers.


3. Build Your Grid

Since you already decided where to place the building, you can set your 2x4s on the ground to make an “L” shape in place where the walls of your building will be.

At this point you will need to know some measurements from the skids on your building. If the building is already at your house get out your tape measure and writing utensil and mark off the distance between the skids on your building. Mark these distances on the shorter 2×4. Our 12’ wide cottages all have a standard pattern which is shown in the diagram below.

12x20 Block Shed Foundation diagram
Your diagram doesn’t have to be beautiful to be functional. Here is a rough sketch that we use for our 12×20 sheds. Skids #2 & #4 are not load bearing, so placing block under them is optional.


Pro Tip! Be sure your diagram is 100% accurate for skid spacing.

Pro Tip! As you build your grid of block piers, be sure they are centered under skids for maximum stability.

Once you’ve marked the shorter 2×4, you can start to place your blocks. I usually start with the highest corner on the grid and work everything else around that, using the first block as a cornerstone. We use a mattock to dig a flat spot in the grass (down to the dirt) for each block so that they sit level.

Block Shed Foundation - digging
Be sure to get remove grass, so you can set the block on bare dirt.


When you place the block inside its prepared nest, use a level and make sure that it is level. If it’s not you may need to dig some more and rearrange the dirt until it is.

Block Shed Foundation - leveling the block
Level the first block of each pier. If you’re off a little on the bottom block, you’ll be off a lot at the top.


4. Level It Up

Using your 2×4 with a level sitting on the narrow edge, find the pier that sits the highest. All the other piers need to match this one. Using different sized blocks, stack on top of your base so that they are all sitting perfectly level with each other. In some situations, you may need to replace your original base block with 2 blocks of smaller size to reach the correct height.

Block Shed Foundation - leveling the stacks
Level from the highest corner, and bring each stack of blocks to that height.


Block Foundation for Shed - leveling the stacks
Experiment with the various block thicknesses, and you will quickly find a combination that works.

To watch how this works in real life, here’s a video of another one of our delivery teams building a block foundation for a shed.


DIY block foundation for sheds?

If you’re thinking, “I don’t DIY my block foundation!” — then what? As you can see, our delivery guys do build block foundations for sheds. Every day. They’re pretty good at it!

  • Get this: a block foundation set comes free with a shed (within limits, of course!).
  • And delivery comes free with your shed (within limited mileage of any of our sales lots).

If you’d like help getting a shed into your back yard, contact us. We’d love to help.


Related Articles

Shed Foundation 101–The 5 Most Popular Shed Foundations

7 Tips for a Great Shed Placement

How To Build A Gravel Pad


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