If you want to use gravel as the foundation for your shed, it is certainly a cost-effective and easy way to go about it. However, you do need to anchor that shed down. Today we are going to go over that process and what it entails.
Can You Anchor a Shed on a Gravel Ground?
What you will quickly figure out here is that we aren’t actually anchoring a shed into gravel, but building a perimeter for your shed, anchoring that into the ground, and then filling that perimeter with gravel to form the base of your shed. The answer here is that gravel itself cannot be compacted enough to really anchor anything into it. However, gravel does make a good base for a shed.
That said, if you want to really make sure it stays in one place, you should consider anchoring your shed to a concrete slab.
How to Anchor a Shed into Gravel
So, anchoring a shed in gravel is actually quite a lengthy process, more than we have time to cover here today. The first step here would be choosing the type of shed you want to build, what you want it to look like, and what materials you will use.
The next step would be to gather all of your building materials and required tools, such as cutting tools, tools for digging, your drill, screws, stakes, and more. The next step is to choose the right type of gravel for the job, which for anchoring a shed is usually going to be ¾” clean gravel.
Once this has been done, you then need to choose the location for the shed. If building a shed on a slope, make sure that you have the door facing down the hill, just in case water runs towards the shed.
The next step is to outline the perimeter of the shed, particularly where you will be digging for the gravel foundation. This is actually where our step-by-step tutorial is going to start, with digging the hole for the gravel foundation.
Step 1: Dig the Hole for the Foundation
The first step in this process will be to use a shovel, or preferably a mechanized digging tool, to excavate the ground where that gravel foundation will be placed. Assuming that you are working on flat ground, you will need to dig down roughly 6” from the surface of the ground. This provides you with a solid base to rest the shed on.
However, just how deep you dig down into the ground will depend on how large the pieces of wood you are using are. For instance, if you are using 4x6s that are turned on their side, then digging down to roughly 4” will work, as this will allow the first course or the bottom pieces of wood to stay slightly aboveground.
Dig the perimeter first, down to around 4”, and then place the 4x6s on their sides into this perimeter, so that roughly 2” of those wood beams protrude above the ground. Once the perimeter has been dug out and the first course of wooden beams for the frame of the floor have been laid, you can then dig out the center of the shed foundation to the required depth.
Step 2: Add to the Perimeter of the Frame
Once the hole for the gravel has been dug out, and the first course of wooden beams for the frame has been laid, you then want to add the second course, or layer, of wooden beams.
The reason you need to do this is that anchoring the shed into the gravel is best done through at least two courses of beams, if not three.
Therefore, to attach the second course to the first course, use 4” exterior screws every 2’ to 3’ along the perimeter, then use six to eight screws per corner.
Doing so will allow your rebar ground stakes to stay in place as needed. For the best results, you now want to add a third course of wooden beams for added stability and hold.
Step 3: Anchor the Frame Into the Ground Below
Now is the time for you to secure or anchor the shed frame into the ground below. To do this, you will need to use a ½” auger bit to create holes through all three courses of the perimeter every 6”.
With the holes drilled, you will then use a sledgehammer to pound 2’ rebar stakes through those holes and into the ground below.
This will effectively anchor the shed to the ground. If you have used more than three courses of wood for the perimeter of your shed, you may need to use longer rebar stakes.
Step 4: Tamper, Add a Liner, and Add Your Gravel
Before you can add the gravel into your foundation perimeter, you first need to use a tamper to compact the dirt within the frame. Make sure that the dirt is packed down to at least 4” under the top of the perimeter, as you need room for the gravel. Also, make sure that the dirt is totally level once tamped.
Once the soil has been tamped down, you then want to add a layer of weed barrier or construction fabric over top. You need this to be under the gravel. Spread out this layer and fold it up several times along the perimeter to allow for a good hold once you secure it. Use a staple gun or hammer tacker to secure it to the inside of the perimeter.
With that done, you can now pour the gravel into the perimeter of the foundation. You need to use a gravel rake to make it level. Once the gravel is level, use a tamper to pack the gravel down. Now you should have a gravel foundation for your shed, with the perimeter of the foundation securely anchored into the ground.
Mistakes to Avoid, Tips & Tricks
Let’s quickly go over some tricks and tips to make this process easier and more successful.
- Make sure that you use ¾” clean gravel. Anything larger and you won’t be able to compact it as needed.
- Always make sure to tamp the soil and then the gravel on top separately. You need both the soil under the gravel and the gravel itself to be very compact for the shed that will sit on top.
You should now know exactly how to build a foundation for your shed out of gravel, and how to anchor the perimeter into the ground below.