Gravel shed foundations are one of the most straightforward, economical, and durable types of shed foundations out there. In addition, they’re also one of the simplest to install on your own.
So, whether you’re a seasoned DIYer or just a homeowner looking to prep the site for your new shed, this guide should give you all the info you need to get the job done. Plus, we’ll throw in some tips and tricks we’ve learned ourselves over the years as professional gravel shed foundation installers.
Why Install A Gravel Shed Foundation?
If you’re reading this article, you’re most likely set on building/installing a gravel shed foundation. If not, here are a few more reasons why it should be your shed foundation of choice. (If you prefer, check out our video guide to installing your gravel shed foundation.)
1. Gravel is the best type of foundation for your shed
There’s nothing quite like a gravel foundation for protecting a shed.
First off, it drains much better than a flat concrete pad. That’ll help protect the runners and joists under your shed from rotting and decaying.
Second, it supports your shed much better than concrete piers or shed foundation blocks. A gravel shed foundation distributes the weight of the shed evenly across all parts of the frame, instead of resting on only a few points with gaps in between. That’s especially important if you plan to store heavy equipment or a vehicle in your shed.
2. Gravel is one of the easiest shed foundations to install
Anyone with at least intermediate construction/tools skills can handle installing a gravel shed pad. Plus, there’s no need to get a concrete truck in your yard to pour this foundation! You can haul all your supplies in with a wheelbarrow and use hand tools to do the work. (We’ll be honest, though, power tools will really speed up the process and save some sweating!)
3. Gravel is one of the most economical types of shed foundation
For a durable foundation that will support your shed adequately, it’s hard to find a better priced option than a gravel pad. Both materials and labor will be less expensive than for a similar foundation built from concrete. If you’d like more info, check out our article on the pros and cons of concrete vs gravel shed foundations.
So, now that you’re (hopefully) convinced that gravel is the way to go, here’s how to install your gravel shed foundation, step by step.
Step 1: Select the site for your gravel shed foundation
There’s a number of factors that go into selecting the best site for your shed and its foundation. There might be one really obvious location on your property, but if not, here are some factors to consider:
The layout of your yard can make or break your shed foundation (and shed for that matter). Ideally, your shed foundation should be at:
a. A site with good drainage
If possible, your shed should be at the highest spot in your yard. That’ll keep water draining away from the shed and everything inside it. If it doesn’t make sense to put your shed at the highest spot in the yard, choose another location where water can drain away. You’ll avoid flooding your shed and discourage rot, mold, and mildew from taking over.
b. A site that’s not too sloped
With drainage in mind, it might be tempting to choose a site on the side of a hill. Don’t do it! (At least if you can help it.) Keep in mind that the steeper the slope you build on, the more you’ll have to dig out/build up to make your shed foundation level. A gentle slope is better; an almost level site is best.
c. A site on undisturbed ground
Keep your shed foundation away from areas where there’s been any digging/excavation in recent years. You don’t want to install your foundation only to have it start settling. This is especially important if your home was recently built; make sure you don’t pick a spot that was excavated during construction and just recently backfilled.
d. A site without obstructions or debris
This one is pretty straightforward. If you have to dig up stumps, remove brush, or otherwise clear the site, you’re in for some extra work and sweat, especially if you’re working with hand tools.
e. A site with good lighting
If your shed will have windows, it doesn’t make sense to put it in a shaded area. Think about where the shadow of your house will fall, as well as the shadows of any trees or woods around your property. Plus, more sunlight reduces the risk of algae or mildew taking up residence in/on your shed.
2. Utility Lines
Here’s a fact: if you stick a shovel into a gas or electric line, your day is going to get a LOT more complicated. When planning where to put you’re shed foundations, make sure you know exactly where your utility lines are. You probably won’t need to dig that deep for a shed foundation, but the stakes that fasten the perimeter lumber could go deep enough to hit something. It’s always better to be safe than sorry!
3. Local Ordinances
Many townships and boroughs have specific regulations which govern where outbuildings can be placed on a property and what percentage of the property or yard those buildings may cover. Be sure to research your local ordinances, zoning regulations, and/or building codes to make sure you’re in compliance. Specifically check:
This covers how far your shed foundation must be from primary structures, roads, property lines, and easements, like overhead power lines.
This governs what percentage of your yard or property can be covered by your new shed. Photo: City of Bellevue, WA
c. Frost Proofing
If you live in an area that experiences significant levels of frost during cold months, there may be regulations regarding exactly what type of foundation and/or footings your shed will need. Depending on the type/use of your shed, this may preclude you from installing a gravel shed foundation.
One option (which we’ve done numerous times for past customers) is to install concrete footing piers at each corner of the shed foundation and then build a gravel shed foundation around the piers at the same height. This option offers the stability of concrete footers with the drainage of a gravel foundation.
Some municipalities may require your shed to be anchored through the gravel foundation to increase stability during high winds and storms.
Check first with your township/municipality to see what they require. If you’re buying a prefab shed, check with the shed company to see what anchoring system they offer or recommend that would meet local requirements.
Oftentimes, regulations only apply to buildings over a certain size; if your shed is small enough it may be excluded. It’s always a good idea to check beforehand, though.
Keep in mind that if your property is part of a homeowner’s association (HOA), the HOA may have additional requirements for sheds and gravel shed foundations.
Finally, think about the aesthetics of your property. Where will your new shed look the best? Depending on how much effort is going into the exterior of your shed, you may want to place it where it can enhance the curb appeal of your home…an extra plus if you hope to sell your property sometime in the near future.
Note that some municipalities actually have specific regulations governing what materials may be used on shed exteriors that face public streets. Photo: City of Northglenn, CO
If you’d like more info on selecting a site, we have an entire article dedicated to choosing your storage shed location.
Step 2: Gather supplies for installing your gravel shed foundation
Once you have the site selected, it’s time to collect the supplies for installing your gravel shed foundation.
1. Tools for installing a gravel shed foundation
If you’re a seasoned DIYer, you’ll probably have most of these tools on hand already. While every part of the job can be done with handheld tools, there are a few power tools that will make the job much simpler and faster. If you don’t own them (or have a friend who does), you can rent them by the day at a fairly reasonable rate. Photos: Home Depot
a. Tape measure
This one’s a given for any construction project!
b. Marking paint
For marking straight lines for the edge of your foundation. Alternately, you could use stakes and string lines.
A carpenter’s level (stick level) will be key to the success of your gravel shed foundation installation. It’s ideal to use a level that is at least 48” long.
d. Drill w/ ½” auger bit
This will be for drilling holes to stake down the shed foundation perimeter. The auger bit should be at least 18” long.
For staking down the foundation perimeter.
f. Circular saw
A power saw will speed up cutting the lumber for your perimeter. If you don’t buy precut stakes, you may also want a metal-cutting blade for cutting rebar stakes to anchor the perimeter.
g. Screw gun
Screwing the corners of your perimeter together before staking will keep things much tighter for the life of your gravel shed foundation. You could also use your drill for this.
h. Staple gun/hammer tacker
Used to fasten the stabilization fabric to the foundation perimeter before you add gravel.
Whether you end up doing all the excavation by hand or just use the shovel to clean up the edges, it’ll be your best friend for this project.
For raking gravel of course! This will make it easy to get your gravel level before you compact it. A concrete rake is ideal, but a landscape rake or dirt rake could also work.
This is to compact the gravel and lock it into place.
This will make hauling and spreading gravel much easier than using only a shovel.
m. Personal protective equipment
You’ll need hearing and eye protection when using power tools. Work gloves are also strongly recommended.
n. Laser level (optional)
While a typical straight level is useful for leveling in one direction, a laser level can be extremely useful for finding the overall slope of your gravel shed foundation location. If you don’t have your own laser level, you may know a landscaper or contractor who would let you borrow theirs for an hour or two. Just remember to ask nicely!
o. Mini skid steer (optional)
A mini skid steer will speed the job up A LOT. This is especially true is your gravel shed foundation will be installed on a slope. Mini skid steers can be rented for about $200-$250/day or about $700/week.
p. Plate compactor (optional)
To really get your gravel shed foundation compacted well, there’s nothing better than a gas-powered vibrating plate compactor. It will not only save you a lot of time with the hand tamper, it will also pack your gravel much tighter and make a firmer base for your shed. You can usually rent a vibratory plate compactor for about $80-$100/day.
2. Materials for installing a gravel shed foundation
Once you have the tools collected, it’s time to gather (or plan for) the materials you’ll use to actually build your gravel shed foundation. You may want to do steps 3 and 4 first, in order to get a better idea of how many materials you’ll need to buy.
a. Pressure-treated lumber
Pressure-treated lumber is the material of choice for building the perimeter/retaining walls for your gravel shed foundation. In fact, some municipalities may even require that you use pressure-treated lumber.
When purchasing lumber, choose a size at least 4×4 or larger and make sure that it’s not only pressure-treated, but also rated GC (for “ground contact”). Here at Site Preparations LLC, we use 4×6 GC pressure-treated lumber for all the gravel shed foundations we install.
For a shed pad on level ground, you’ll need lumber equal to the total perimeter length; for a pad on a slope, you’ll need to buy extra for each additional level you need to build up. Photo: Home Depot
b. ½” rebar
You’ll use 2’ pieces of rebar to stake the perimeter lumber down into the ground. If your perimeter lumber will be built up more than 2 or 3 layers, you’ll also want some 16” rebar stakes for fastening multiple layers of lumber together.
You can either buy rebar precut at 2’ or buy longer pieces (up to 20’) and cut them to length yourself with the circular saw and metal-cutting blade. Use hearing protection when cutting metal! Photo: Home Depot
c. 4” exterior screws
You’ll use these to fasten together the corners of your perimeter. Make sure the screws you choose are rated for exterior use and contact with pressure-treated lumber. Screws should have hot dip galvanizing or equivalent coating, like polymer. A bugle head design is ideal for countersinking into the wood. At Site Preparations LLC, we use 4” Grip Rite exterior screws. Photo: Home Depot
d. Stabilization fabric/geotextile/weed barrier
There are a couple of reasons to use a stabilization fabric or weed barrier when installing your gravel shed foundation.
For one thing, it helps prevent weeds from sprouting up and taking over your shed pad.
Second, it helps to separate the gravel from the dirt beneath it, adding an extra level of stability to the finished foundation. Keep in mind that the fabric you choose will need to be strong enough to support the weight of the gravel and the shed without puncturing.
At Site Preparations LLC, we use a woven stabilization fabric with a Class 3 rating according to the American Association of State Highway and Transportation Officials (AASHTO) M288-17 standards. A woven Class 3 fabric has a tensile strength of 200lbs and a puncture strength of 90lbs and is designed to be used in road construction. Photo: Home Depot
e. Crushed stone
This is going to be the key ingredient of your shed foundation, so make sure you select the right type. There are a few important things to keep in mind when purchasing gravel for installing your shed foundation.
i. Make sure you use crushed stone, NOT actual gravel
This article is all about “GRAVEL shed foundations”, but it’s important to note that we’re actually referring to CRUSHED STONE. Real gravel (also referred to as river stone) is smooth and rounded on the edges.
DON’T use river stone for your gravel shed foundation. With its rounded corners, it won’t lock together properly when compacted, so it will continue to shift and settle once your shed is in place.
DO use crushed stone for your gravel shed foundation. Because it has jagged, uneven edges, it will lock together tightly when compacted and form a firm base for your shed. Photo: Ed’s Landscaping Supply Inc.
ii. Make sure you choose the correct type of crushed stone
Crushed stone comes in a variety of sizes and types. The best type of crushed stone for a gravel shed foundation is ‘¾” clean’, sometimes also referred to as ‘clean stone’, ‘¾” washed’ or ‘#57’, depending on the supplier. ‘¾” clean’ is stone that has been screened through a ¾” square screen and has been washed to remove stone dust and other residues.
It’s important to buy ‘clean’ stone for installing a gravel shed foundation. Some people recommend using a crushed stone mixed with stone dust or ‘fines’ because it packs down harder. (These types of stone are sometimes referred to as ‘crusher run’, ‘#411’, or ‘#21A’, depending on the supplier.)
The problem with using ‘crusher run’ stone for a gravel shed foundation is that the mixture of stone and dust will pack TOO HARD, preventing water from draining through the shed foundation properly and causing puddling and/or runoff. ‘Crusher run’ stone is great for uses where it will be driven on (like a driveway), but ‘¾” clean’ stone is the best for a gravel shed foundation.
iii. Make sure you calculate how many cubic yards of stone to buy
You’ll want a minimum of 4” of stone at every part of your foundation, so figure accordingly. Take the width and length (in feet) of your foundation and multiply it by the average stone depth. Divide that number by 27 and you’ll get the cubic yards needed for your pad. For a more in-depth guide, check out our article on how much gravel is needed for a shed foundation.
Step 3: Mark the corners of your gravel shed foundation
Now it’s time for the fun to start! Grab a couple of stakes or some flags that you can use to mark off the corners of your foundation. (If you already have the 2’ rebar on hand, that can work well.)
It’s important that the outside edges of your gravel foundation be about 3’ longer and wider than the dimensions of your shed. That’s because you should have at least 12” of gravel on each side of your shed, plus another 6” or so for the foundation perimeter.
To get started, stake two corners of your shed foundation. If your shed will be next to a driveway, a fence, or anything else with a straight edge, you’ll probably want to mark the first side of the foundation parallel to that. You can then base the rest of your measurements off that straight line.
With two corners marked, you can measure the other side based off of those marks. Once all four corners are marked, take a quick diagonal measurement in each direction to make sure your corners are square. You can fine tune this later when you install the perimeter, but you want to make sure it’s close before you start digging.
When you’re happy with the placement of your corners, use the marking paint to paint a straight line along each edge of your pad location.
Alternatively, you can use stakes and string to mark the edges. If you do that, it’s a good idea to keep the stakes out a couple feet from the actual corners (as shown in the diagram) so they don’t become loose during digging.
Step 4: Measure the slope where you will install your gravel shed foundation
You’ll need to know what the slope is at your shed pad location so you can determine exactly where you’ll need to excavate and how many materials you’ll need. There are several ways to do this:
1. Laser level
A laser level or laser transit with a receiver is the simplest way to level your site and only requires one person. First, you’ll want to take a reading at the highest corner of your foundation site. Based on that first corner, you can determine the difference in slope at each of the other corners by measuring how far up the transit rod you need to move the laser receiver. If you’re not familiar with using a laser level, you might want to watch a video demo like this one or this one.
2. String level
This is another simple way to check for level. If you have stakes set up at each corner, simply tie a piece of nylon mason’s line (or other non-stretchy string) between the stake at the highest corner and the corner you want to measure. Attach a string level to the line and make sure it’s level. Then, simply measure down from the string at each corner to find the difference in height between those two points.
3. Straightedge and level
This method works well if your shed foundation will be relatively small. Find a very straight piece of lumber (a 2×4 or 2×6 works well) the length of one edge of your pad location. Lay your level on top of the lumber straightedge to effectively create a much longer level. Place one end at the highest corner of your site. Hold the other end of the straightedge level at the next corner and measure down to the ground to find the height difference between those two corners.
Step 5: Excavate the site for installing your gravel shed foundation
Often, steps 5 and 6 will take place simultaneously. Once you have the site marked off, it’s time to start digging. How you excavate depends on whether you plan to build up or dig down to make your shed foundation level.
The key consideration is where your door will be placed. It’s ideal to get your door as close to ground level as possible. That will allow easy access for people, equipment, and whatever else needs to go in and out of your shed.
If the door will be on the uphill side of your shed, you’ll want to build up the downhill end of your gravel shed foundation to make it level.
If the door will be on the downhill side, you’ll want to cut away into the slope to create a level area for your shed. This style is best for slight slopes or foundations that meet the edge of a driveway; for steeper slopes, use the combination
In some cases, such as on a very steep slope, you may build up one end of your shed foundation and dig out the other end. Dirt excavated from the uphill side can be spread in front of the foundation on the downhill side to create a dirt ramp up to the door.
Regardless of what type of excavation your shed foundation requires, you’ll want to start at the lowest side of the site. Move along your marked line and dig away about 2”-4” of topsoil in a strip wide enough to lay down your first piece of perimeter lumber.
If you’re using 4x6s turned on edge to build the perimeter, digging down 2”-4” will allow the first course to stay several inches above ground level. Dirt excavated from the inside of the perimeter can be used later as fill on the outside to bring the lawn up to level with the edge of the foundation.
Once the first piece of lumber is in place and leveled, you’ll continue around the perimeter of your shed foundation, digging out the soil to make a level space for each piece of lumber.
Step 6: Build the perimeter for your gravel shed foundation
It’s extremely important to get your perimeter exactly level! A level perimeter will be the easiest way to level the gravel when you add it inside the foundation.
Continuing from the lowest side, dig out a strip of topsoil and add 4x6s (with the 4″ side turned down) the whole way around the perimeter or until the first course is below ground level.
You’ll add each piece of lumber as you excavate and level the spot for it. As you place each piece of lumber in the first course of the perimeter, check to make sure it’s level. If it’s slightly off level, you can use your sledgehammer to tap on the high end or add a little dirt back under the low end to correct it.
When there is at least one layer of lumber around the whole foundation, double-check your diagonal measurements to make sure your perimeter is square.
Once the first course of lumber moves a couple of inches below ground level (if your shed foundation is on a slope), you’ll want to start the second course.
If you’re building up to level, start at the low end again, overlapping the corners of your lumber with the course below (like a log cabin corner). Continue the second course the rest of the way around the perimeter or until it too moves below ground level (at that point you’ll start the third course).
If you’re digging down to level, start the second course stepped back from the first to the point where one end is completely above ground level. Continue the second course the rest of the way around the perimeter or until it too moves below ground level (at which point, you’ll start the third course). You can cut a 45-degree dog ear on the exposed end of each course of lumber to create a more finished look.
As you add each piece of lumber to the perimeter, use the 4” exterior screws to fasten it to the pieces next to and/or below it. It’s especially important to focus on screwing the corners together to keep them tight. Use 6-8 screws per piece of lumber per corner. Additionally, screw each piece of lumber to the course below it with two screws approximately every 2’-3’. This will assist the rebar stakes in keeping the perimeter from shifting.
Step 7: Add any necessary bracing to your gravel shed foundation
If the slope at the site requires one end of your gravel shed foundation to be built up, you may need to add bracing inside to help support it. At Site Preparations LLC, we typically brace shed foundation walls that are 16”-20” or higher. The longer the built-up wall is, the more important bracing is.
We use and recommend a style of bracing called a “deadman”. (Don’t ask us where the name came from!) In this design, the “deadman” (“deadmen” if there’s more than one) are pieces of lumber which are attached perpendicularly to the braced wall. On a built-up foundation, the “deadmen” are on the inside; on a dug-out foundation, they’re on the outside.
On lower applications, the “deadmen” may be fastened with screws to another piece of lumber running parallel to the braced wall. On higher walls, the “deadmen” are actually built into the wall. Either way, use plenty of 4” screws to fasten the ends of the bracing into the wall of the perimeter.
Once the foundation is backfilled and the gravel is added, this “deadman” brace will help to tie everything together and keep the perimeter wall from pushing outward (or inward) over time.
Step 8: Anchor your gravel shed foundation with stakes
Once your perimeter is completed or you have 3 layers of lumber in place, use your drill and ½” auger bit to drill holes through the perimeter every 6’-8’.
Pound 2’ rebar stakes through the perimeter and into the ground. If you didn’t buy rebar precut into 2’ stakes, you can cut it yourself with your circular saw and a metal-cutting blade. You could also use a reciprocating saw or a grinder. Always wear ear, eye, and hand protection when cutting rebar!
If your foundation perimeter is more than 3 courses high at any point, drill again at every other course of lumber (starting at the 2nd course) and use 16” rebar stakes to fasten higher courses of lumber to the lumber below.
Step 9: Level and backfill the dirt inside your gravel shed foundation
Now that the perimeter is in place, you can finish removing the topsoil and excavate any remaining high spots inside the foundation. It’s important that the dirt inside your shed foundation is at least 4” below the top of the lumber perimeter to allow room for the gravel.
If the site is sloped, some people recommend adding perforated drainage pipe at this point to drain water from inside the downhill end of your foundation into the lawn. However, if you’re using ¾” clean stone as recommended, additional drainage is completely unnecessary since water will drain straight through your foundation and into the ground below. The only time we add drainage is uphill on the outside of a dig-out foundation to channel water around the foundation instead of onto it, but even that scenario is very rare.
Use extra topsoil to fill any gaps between the lawn and the outside of the foundation. If your site is nearly flat, you can use the extra dirt to slope the lawn up to the top of the perimeter. That will make a nice, tight line between your lawn and the edge of the shed foundation. If your site is sloped, use extra dirt to even the grade, especially on the side toward the door.
Make sure all the dirt inside your shed foundation is well-packed so it won’t sink over time. Use a tamper if necessary. If you’re using heavy equipment, like a mini skid steer, you can use its weight to help pack the dirt.
Step 10: Add construction fabric to your gravel shed foundation
Once the dirt is level, spread the construction fabric/weed barrier out over the inside of your shed foundation. Fold a few inches of the fabric up the side of the perimeter and use a staple gun or hammer tacker to fasten it.
Step 11: Add gravel to your shed foundation
Finally, it’s time for the gravel! Dump the crushed stone inside the completed perimeter and spread it around with a concrete rake. To properly support your shed, it’s important that there is a minimum of 4” of gravel at every part of your shed foundation.
In addition to a gravel rake, you could also use a straight piece of lumber like a 2×4 or 2×6 to create a screed board for leveling the gravel. Simply drag the screed board across surface of the foundation to push gravel from high spots down into low spots.
Step 12: Tamp your gravel shed foundation
This step is crucial. Tamping the gravel is what will lock it in place and create a strong foundation for your shed for the coming years.
We’ve found it best practice to start about 12” in from the perimeter and work inwards. Use a circular/spiral pattern rather than going back and forth. That will keep everything packed evenly across the entire foundation rather than pushing the gravel to one side.
Once the center is tamped tight, go back to those outside 12” and tamp them as well. This keeps the gravel at the edge packed tight and level between the perimeter and what’s already tamped in the center.
‘¾” clean’ stone is already 90%-95% compacted when it comes from the supplier, so you should only need to go over it once with the compactor.
Congratulations, your gravel shed foundation is installed!
Of course, if you decide that installing a gravel shed foundation is more than you want to tackle yourself, you can always hire a gravel shed foundation expert to install it for you. Just make sure the company you choose is familiar with gravel shed foundations specifically.
If you’re in the northeastern United States, we’d be glad to give you a free estimate ourselves.