A Guide to Setting Up Your Shed Foundation

How to Build a Shed Foundation
Spread the love

Taking on the task of building a shed yourself can be an exciting project, but it can also be daunting if you’re doing it for the first time. Setting up the shed’s foundation is the first step in getting it built, and breaking it down step-by-step can make the rest of the process much easier. Having a good foundation will ensure that the other parts of your shed are safe and secure, making it easier for you to customize it however you want. Here’s how to get your shed foundation down pat:

Setting Four Posts

The first step in building a foundation for a shed is to set four posts. You’ll need the following materials to accomplish this: 

  • 4×4 pressure treated posts (8 ft)
  • Post-hole digger
  • Wood for the outside frame (Rim Joist)
  • Stakes for starting points
  • Cement
  • Level
  • Square
  • Masonry string
  • Spray paint for guidelines

After ensuring you’ve got everything you need to get started, following this step-by-step process can ensure that you set up your foundation correctly. 

Check Regulations

Before taking measurements and digging, double-check the city’s regulations. You must also be sure to clear out any gas, water, and electrical lines. 

Take Measurements

Start by choosing and staking a corner as the starting position, then measure the width of the back according to your shed foundation plans and set the second back corner stake. Continue by measuring the original stake’s depth, followed by the width from the front stake to set the final one in place. Ensure that your postings are even by measuring diagonally. The stakes should be positioned to create a perfectly square perimeter.

Wrap masonry string around the outside of the stakes so that the workspace is clearly defined.

Dig, Set Posts, and Re-Measures

Before you start digging, be aware of the ground height from one post to the other. This will ensure that the depth you dig will level out every post. Using square, plumb posts can make a difference in setting up straight, level walls and creating the foundation for a sound structure. After that, measure for the outside structures, taking into account the framing as you do so.

Pour Cement

Once you’re certain everything has been measured accurately and that every post is in place, mixing the cement is the next step. 

When learning how to square a shed, it’s especially handy to have a level during this stage. Add dry cement to the hole made by posts, which should be properly sitting against the masonry string. Fill it with water, then use the level to ensure everything is in place before adding more cement and water. You should aim to have perfect posts before the cement sets. Repeat the same process for the next post, making sure to double-check the measurements between posts as you go along. 

Ensure Posts Are Square Before Cement Sets

This step should be done continuously as the cement is being poured, but double and triple check after you’re done to ensure not too many adjustments are needed before the cement sets. Once the posts are sitting perfectly, it’ll be much easier to add the middle posts required to have a completed shed foundation. 


Setting up a shed foundation is the most crucial task in building your shed. It requires precision, a meticulous eye for measurements and details, and a penchant for handiwork. Even if you haven’t fully developed all these skills, following this straightforward step-by-step process will allow you to accomplish everything required for a solid foundation for your shed. After that, the rest will be easy-peasy!

Are you looking for the cheapest way to build a shed? At Shed Mechanics, we provide you with extensive guides, tutorials, and tips on saving by creating your own custom-designed sheds. Sign up for our newsletter for the latest tips and tricks today!

Shed Plans photo