If you’re wondering how deep should a gravel base be for a shed you’ve come to the right place.
Before we get straight to answering this question, let’s first answer some common questions about gravel shed pads.
Can You Put a Shed on Gravel?
As long as the construction is performed properly, it is possible to build sheds on gravel. In fact, it is a great alternative shed base because it’s very stable, easy to work with, and more cost-effective than most other base materials.
It’s also not a permanent structure. If for some reason you need to remove it, it’s a lot easier than trying to remove a concrete slab.
Why Put Gravel Under a Shed in the First Place?
All sheds need to be positioned on a solid foundation of some kind to prevent movement and keep them in place. Gravel is one kind of foundation that can be used.
To provide a barrier from moisture
Grass and regular dirt are not suitable for a shed base. They can get wet, which can create movement and leave you with a warped and unstable building. In addition, dampness can rise up into the shed structure, damaging the floor and walls.
A gravel base will prevent any damp ground from coming in contact with the shed components.
To provide stability
For one thing, it provides better stability and support to your shed than foundation blocks. The weight of the shed is distributed extremely evenly so no one spot of the shed will be shouldering all of the burdens. This is very important if you plan on storing heavy machinery, tools, or vehicles in your shed.
To provide better drainage
Another important reason why gravel is a great foundation option is that it drains moisture and water a lot better than other options. The open coarse nature of gravel rock means that during very wet weather, water can flow through freely.
It’s easy to install
Perhaps one of the most popular reasons why gravel shed foundation is great is because it is very easy to install. You don’t need a lot of experience to handle the job yourself, just a few hand tools, power tools, and basic construction equipment that anyone can buy at the store.
It’s a cheaper option
Yet another fantastic reason that makes a gravel pad better than a concrete pad or a plastic shed base is that it is so cheap to buy. You don’t need to break the bank or spend months saving up to get enough gravel for your shed. It’s a relatively simple project that you can started on right away.
What kind of gravel is best for a shed base?
Technically speaking, the gravel that is most suitable for a shed base is crushed stone. Real gravel is a natural rock from the ground or river beds and tends to have a smoother outer surface.
Crushed stone mixtures are made by machinery as they are crushed through a process. This kind of stone is more suitable because it has more jagged edges from crushing that lock together nicely when compacted. The best grade crushed gravel/stone is around 3 to 3/4 inch in diameter.
The rock mixture should then be mixed with a smaller rock to make a solid shed base resistant to movement and settling. This is the type of gravel mix that provides the durability and affordability that gravel pads are known for.
How deep should a gravel base be for a shed?
As discussed previously, building a gravel foundation isn’t too difficult, and part of the reason why is that gravel bases don’t need to be too deep. When it comes to digging up the grass and soil, you don’t need to remove it very much at all.
The general consensus is that 4 to 6 inches are all you need to have a suitable shed gravel base. The reason is that anything less than 4 inches deep will not have enough space for moisture drainage, increasing the chances your shed will suffer from internal moisture damage.
How to Build a Gravel Shed Pad
The first thing when it comes to building a gravel shed pad is to take stock of what materials and tools you will need.
Prepare tools and materials.
Let’s say, for example, you want to build a shed 12 feet by 12 feet. As a rule of thumb, you want about 3 feet of extra length and width for the gravel base foundation.
Crushed stone mixture
It’s important to note that there are different definitions of gravel or crushed stone. you’ll need to talk to your supplier about their products and which one is most suitable for a shed pad.
When in doubt, it is preferable to go with the more jagged crushed stone variant of gravel. You’ll have a stronger foundation base; rounded stones do not lock together as tightly.
Pressurized wood
You’ll also want to get what’s known as pressurized wood. This will act as the frame of the gravel pad itself. As the name implies, pressure-treated or pressurized wood is stable and has a longer lifespan. Despite this, it’s very inexpensive to buy a few dozen feet. These are all the materials you need for building a gravel shed pad.
Tools and equipment
As for tools, you don’t need much, either. A measuring tape, a saw of some sort, a shovel, and a power drill will be all you need. A wheelbarrow is also highly recommended for moving and pouring the gravel or crushed stone mix with ease.
Find the best spot
Next, you need to have a spot on your property selected for where you will build your shed and gravel foundation. It should ideally be on as flat or level ground as possible. If none of the land you have is even, you can find out how to mitigate this in the next FAQ section.
Start digging
Once you’ve selected your spot, you’ll need to dig out the soil and the ground. This will probably be the most laborious part of the process as you’ll need to dig a potentially 15-foot by 15-foot area, depending on the size of your shed that you’ve calculated.
Most importantly, this is where questions like how deep should a gravel base for a shed be come into place. As mentioned, 4 to 6 inches should be enough. If you’re unsure, you can always use a yardstick or a measuring tape to help you out, as this is a very important part of the process.
Be sure to remove any weeds that may be growing on that spot by uprooting them. If your property is prone to weed infestations, you may want to invest in a weed barrier as well.
Place a wood barrier
Once the ground is dug up, then place your pressurized wood barrier. Cut 4 long 2×4, 2×6, or 4×4 boards to size so that they form a long square that will act as the perimeter of your gravel foundation pad. Screw them together at the corners, preferably with an electric drill power tool, so they are tightly secured.
Pour the gravel
Now that you have your hole dug up and your wood barrier in place, it’s time to pour in the gravel itself.
As an optional step, place your weed barrier directly on the ground and under the gravel, preventing any weeds from growing through the gravel.
Once all the gravel is poured, level it out as much as possible, so it is flat and smooth. The gravel should be level with the top of the board perimeter and not go over it, not even by a centimeter. You can use various tools to help smooth out the gravel, like a small rake or a broom if it is heavy enough.
Once the gravel is level with the barrier, you’re all done! That’s all it takes to set up and build a gravel base for your shed.
How to Build a Gravel Shed Base on Uneven Ground
It’s important to build any kind of structure on the ground that is as level as possible, but what happens if your backyard has only uneven ground?
The simple answer is that concrete blocks actually make the best foundation choice when dealing with uneven ground. But there are workarounds with gravel bases if you’re still dedicated to that method.
If the ground is only slightly uneven, you can try to level it out yourself manually by using a shovel and moving around dirt to equalize all the areas.
If the gaps are too big, you can use something called pea gravel to fill them in. This material is strong enough to avoid any future sagging.
How Necessary is Frost-Proofing?
If you live in a cold enough area, you might want to consider frost-proofing your shed and shed base. Some may not realize that foundations need to be frost-proofed as well, including gravel pads.
While frost-proofing can be more intensive, they end up making stronger and longer-lasting shed foundations. You should really only worry about frost-proofing if your shed is especially large and if you live in cold climates that experience major frost several months per year.
Do I Need a Permit for my Shed?
Depending on where you live, it may be against the law to build a shed without a permit, even if on your own private property.
The general rule of thumb is that permit laws, if they apply, refer to the size of the building in terms of square feet. Some cities require you to obtain a permit if your shed is over 100 square feet. If it’s below that then you’re fine, but if it’s larger and you still choose to continue building one without a permit, you can be met with a hefty fine.
One of the reasons these permits exist is that large sheds can interfere with things such as power cables. So when building a taller shed, a permit verifies that you understand that it won’t accidentally touch any airborne wires or cables.
