A long lasting shed will need a sturdy foundation to keep it level and protected from moisture. Follow these steps to build your shed foundation. First check local building codes or homeowners association guidelines regarding permits, frost lines and location specs in your yard. Also call eight one one to check for underground utilities. Pick a spot for your shed that’s close to level and doesn’t collect water. It’s also good to have three feet of clearance around the perimeter from things like fences and structures to ensure you have enough space at your location. Mark the shed area with Mason string and batter boards to square it. Measure three feet along one string and four feet along the adjacent string. The distance between the two points should be five feet. Adjust as needed and check the other corners. You can build your foundation several ways on grade foundations are for areas that don’t freeze.

One option is a concrete slab with sill plates on top. Another option is masonry blocks set on four inches of gravel. The next methods are for Frostproof foundations. The footers are set below the frost line to prevent shifting during freezing temperatures. You’ll need additional strings and batter boards to line up postholes and runners. The first method uses concrete tube forms on gravel with post based brackets on top for our shed. We’re using posts set on concrete footers, dig holes about four feet apart, 12 inches in diameter, and 12 inches below the frost line. Pour about four to six inches of gravel in the hole, compact it. Then add concrete following the manufacturer’s directions. Once the concrete has cured, set a post on top of the footer, making sure the post is plum and holding it straight. Add concrete around the sides and top off with soil. After all the posts are set, determine the height you want for your shed floor and mark one post. Use this as a guide to mark the other posts and cut with a saw. Then attach post based brackets and four by four runners.

Next, build the frame with two by fours and nails according to your sheds. Directions. Set the frame on the four by fours leaving an overhang at the ends and attach one side to each four by four with one screw. Check for square by measuring the diagonals. They should be the same. Make any adjustments and secure the other side of the frame to the four by fours. Then you screws to secure the frame at each point that contacts the four by fours. Next set of floor panel at the corner of the frame flush to the edges nailed down the short edge. Check the frame for square one more time and nail down the rest of the plywood. Attach the other floor panels according to the directions. With the foundation set, you’re ready to build the shed kits. Come with detailed instructions to do it yourself or have it professionally installed. Want more great ideas and how tos go to lowes.com/how to or just click to subscribe. Next. Learn how to install French doors in your shed.

How to Build a Shed Foundation

32 Responses

    1. If you don’t want your shed slowly ripped apart by frost heave, you’ll go below the frost line. The only thing you can do is you don’t want to dig so deep is pour a concrete floating slab. It’ll still move with frost heave but it will move the building with it and not destroy it. Either way you are going to be digging.

  1. I was told yesterday by a lowes representative, when they come to install the shed, they don’t do anything to the floor. What about my foundation. and why is it so expensive for them to paint the shed?

  2. Nice video!
    I built a shed foundation over the weekend and attached the flooring only to find out that it is not square by 2 inches. Is life over?

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