Its not a matter of just dumping gravel on the ground if you want a lasting stable solid base to protect your shed. A well-made gravel foundation can support your shed directly or other foundation styles for your shed.
To build a solid stable gravel shed foundation remove the grass and topsoil and level the ground. Compact the loose soil and cover with a weed barrier. Cover the barrier with gravel and spread it out evenly with a shovel and metal garden rake. Use a gasoline-powered compactor to tamp down the gravel. Do the final grading with a rake, and your foundation is ready for your shed.
In this article, Ill show you how to level and square up your site and what type of gravel or crushed stone makes a stable base. Ill discuss how to build a boxed and unboxed gravel pad, and how to anchor your shed on a gravel foundation.
Hopefully, Ill save you a few steps, a bucket of sweat, some money, and youll learn how to build a gravel shed foundation. Quick NavigationWhat is Gravel Shed Foundation?What Exactly Is Crushed Stone?Planning for Your Shed FoundationGravel Pad MaterialsGathering Materials and ToolsMaterialsFind the Tools That You Will NeedRent Tools That You Will NeedHow to Lay Gravel Shed FoundationWhat are Options for Building Gravel BaseGravel Pad in Box1. Prepare Construction Site2. Digging Out3. Build the Frame for Gravel Pad4. Drainage Tile5. Lay Landscaping Fabric6. Pour and Compact the Gravel7. Check for LevelGravel Pad without Box1. Prepare Construction Site2. Shed Pad Preparation3. Build the Gravel Base4. Grade the areaWhat does it Cost to Install Gravel Pad?Anchoring the ShedNotes and TipsConclusion
A gravel shed foundation, or pad is a non-permanent stable structure on which to place or build a shed. It supports your shed on a solid ground level or near ground level pad similar to a concrete pad.
The size of the shed determines the size of the gravel pad, which also determines to cost of materials. The gravel pad should extend a foot or two beyond the sides of your shed too. Gravel pads are best for flat or near flat locations, but retaining walls can help level almost any location.
Check with your local building department to make sure your project meets local requirements. Also, give your local utilities a call too before you put a shovel in the ground and through your phone or cable line. Better safe than sorry.
The type of soil in your area determines its weight bearing properties. A dense gravel or dense sand and gravel soil can support more than 600 kPa or 12531 psf (pound per square foot). A compacted gravel base will provide similar support and stability if properly constructed and drained.
A gravel pad unboxed, boxed, or with retaining walls is an excellent DIY project. However, if you need to excavate a lot of material and construct large retaining walls, you may want to speak to a professional.
Saving a buck or two on something you feel you can do and have the time to do is great. Heavy equipment rental and retaining wall construction may make the professional a better deal though and often includes a warranty.
Most people refer to crushed stone and gravel as if they were the same; they are not. Gravel is a naturally eroded material and crushed stone is just that, mechanically crushed stone or rock. They even have different uses.
Gravel is rounded smooth stones of different sizes and colors found in riverbeds or ancient glacial deposits. It is often comprised of different types of rock material and comes in sizes ranging from to 2 and up to 20 or more inches.
It is used for decorative garden beds, walkways, landscaping, and drainage projects. The smooth rounded stones permit moisture to pass through the gaps between the stones; which also make it difficult to compact.
When choosing a suitable site for your gravel shed foundation consider the slope, drainage requirements, solar gain, and how firm the ground is. You also need to have enough space for the foundation and to be able to build or place your shed.
The best material to use for a gravel pad is crushed stone mixed with finer crushed material and dust. It compacts well and makes a permeable solid stable base with the finer material filling in any airspace. It is often known as crush and run or crusher-run gravel.
Different gravel companies use different numbers or grades to identify gravel size and composition. One company may call it 21-A while another refers to the same product as #411. Check the companys website or call and ask.
Dont use crushed stone that has been cleaned or washed and sorted or graded so it has no fine materials, it wont pack well. It will shift and move around as you try to compact it. The larger the stone material, the more likely it will sink too.
Weed barrier comes in rolls or folded sheets. It is water permeable to allow water through but stops the weeds from coming up through. Youll need enough to cover the full area covered by the gravel pad.
A gravel shed foundation can be built within a pressure treated wood frame or box or without a box on flat ground. The boxed pad, or retaining wall pad, can be used on the flat ground or to create a level base on uneven terrain.
A gravel pad in a pressure treated 4x4 or 6x6 frame or box is also known as a retaining wall pad or a timber frame pad. The retaining wall can hold the ground away from the pad, or keep the gravel foundation in place if the ground is sloped underneath it.
The cost of the pressure treated 44 or 66 timbers for the frame will depend on the perimeter of the gravel foundation, and the elevation due to the slope. A 12 foot 44 is about $20, a 12 foot 66 around $50, and a 16 foot 66 is between $60 and $70. Check with your local lumber store for the best prices.
rebar is sold by the foot in some stores and by the length in others. The longer the length the less the cost per foot, a 10-foot length is about $6. Buy longer pieces and cut with hack-saw or cut-off grinder.
The potential cost for an 11ft x 15ft gravel pad for an 8ft x 12ft shed could be 15ft x 11ft = 165 sq ft divided by 100 = 1.65 cubic yards of stone for every 2.5 = 3.96 cubic yards for a 6 inch thick gravel pad x $40 = approximately $160.00
Youve put time, sweat and money into building a stable foundation for your shed; a little bit more to protect your shed wont hurt. The size of your shed will determine how many anchors you need, and what type of anchor system is best.
A gravel shed foundation may be an easy foundation to build, but its a lot of grunt work too. Whether a free form or timber-framed pad, it must be compacted and as close to level as possible. If its not level, it will fail and damage your shed.
This stone is typically used filling in large areas. This stone is typically used for a base indriveways, roadways, parking lots, under sidewalks, patios, sheds.Limestone pieces up to 3" in size, contains fines, compactswell..
We recommend making the gravel base 2 wider and 2 longer than the size of the shed you get giving you 1 on both sides and ends to help prevent dirt from splashing up on the sidewalls of the building. We recommend a 4 to 6 gravel base of either 3/4 stone also called 57s by some or crusher run. If I had a choice I would go with the 6 deep gravel pad. The recessed pad is not necessary but optional. You could place 6 of gravel down and get 6x6 and frame out around the perimeter of the shed. It is important to think about the type of shed foundations available and which one will work best for your property before you make a purchase online. After the order is complete, it is time to start looking for the right foundation for shed construction.
This kind of depends on whether or not the shed you buy will be located in a wet area if so you may want to consider going with the 3/4 blue stone as it will provide additional drainage benefits over the crusher run. One advantage of the crusher is that it tends to really pact while and kind of turns it to concrete so to speak, but if the area holds water again that advantage now turns into a disadvantage. In most cases, when it comes to the foundation for shed construction, the crusher run will be slightly less money which all things being equal if your shed will be resting in a dry location would work fine, but this will kind of depend on your personal preference if moisture isnt a factor. The location of your storage shed foundation makes a difference when it comes time to choose the materials you are going to use.
This is a question we get asked occasionally about the specific storage shed foundation needed on any given property. And yes, there are certain circumstances where you would be better off with a concrete pad but most of the time this would be when youre buying a garage for sale to store a vehicle and not a shed for storage of mowers, garden supplies or household items which would not need to be placed on a concrete pad. A concrete slab is going to be way more expensive than a gravel pad, but this is not why we would say get a gravel pad. Water will just rest on a concrete pad vs. a gravel pad and especially the 3/4 gravel pad which will let water drain right through the foundation helping protect your building. Now all of the Amish built sheds and Amish built garages at Alans Factory Outlet come with a 40 year pressure treated foundation and that is if you get it with a floor or without a floor. With a floor comes with 4x4 pressure treated skids and if you go without a floor it will have pressure treated 6x6 around the outside of the structure. So water in the short run will not be a problem however if the building is sitting in water most of the time I doubt very seriously you will get 40 years youll be lucky if you get 20 years and that may be a little too optimistic depending how often it is resting in water.
Another option to help the gravel pad and this is more so for larger storage buildings would be to add a concrete pier below the frost line which varies from location to location depending on the county codes and then fill it in with gravel between and flush up to the top of the pier. If youre going to place the piers in the ground please contact us and let us know what size shed or garage youre getting so we can let you know the exact location of the pressure treated 4x4 foundation skids.
Shed foundations are an important part of the construction process. The foundation needs to be level for the doors to open and shut properly. We do not level the sheds or garages so you will need to make sure that you either check to see that the garden shed foundation is level with a bubble string level or with a transit level. You will want to make sure it is level from front to back, side to side and from corner to corner. This is probably the most overlooked issue when it comes to garden shed foundation planning as many people will just kind of look it over with the eye and think looks pretty level without checking to see and true some people are really blessed with the gift of having an eye for that kind of stuff and some people have a good feel for seeing that it is level because they have a lot of experience with grading and leveling, but there are some, me included, that eyeball level it and just visit my display lot and you will see firsthand I have a couple of display sheds that I didnt plan on it but I now can first hand use as a bad pad example from the stand point of not being level and when you open or shut them the doors kind of rub either the top or bottom a little.
We do not recommend putting the sheds on blocks due to setting issues and lack of support the full length of the structure on all of the foundation skids. Also we do not carry blocks on the delivery trailer so from that stand point we do not block the sheds. The base for shed construction is an important element of the construction process. However if you insist that you want your shed on blocks and if your shed is 1020 size or smaller and if you provide the blocks and have them laid out prior to our arrival. You will need to request a sketch of the location of the runners depending on the size shed you get. We will place the shed on the blocks however they will need to be placed level so the doors open and shut properly.
It is also worth noting that the storage sheds are built with pressure treated 4x4 runners and then on top of that are 2x4 floor joist upright and on top of that is a 5/8 plywood floor so the top of the floor is over 7 off of the ground which provides plenty of air flow under the shed so there is really no need to place it on blocks especially if you have down 6 of gravel than the floor is technically over 1 off of the water/dirt ground.
So, whether youre 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, well throw in some tips and tricks weve learned ourselves over the years as professional gravel shed foundation installers.
If youre reading this article, youre 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.)
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. Thats especially important if you plan to store heavy equipment or a vehicle in your shed.
Anyone with at least intermediate construction/tools skills can handle installing a gravel shed pad. Plus, theres 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. (Well be honest, though, power tools will really speed up the process and save some sweating!)
For a durable foundation that will support your shed adequately, its 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 youd like more info, check out our article on the pros and cons of concrete vs gravel shed foundations.
Theres 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:
If possible, your shed should be at the highest spot in your yard. Thatll keep water draining away from the shed and everything inside it. If it doesnt make sense to put your shed at the highest spot in the yard, choose another location where water can drain away. Youll avoid flooding your shed and discourage rot, mold, and mildew from taking over.
With drainage in mind, it might be tempting to choose a site on the side of a hill. Dont do it! (At least if you can help it.) Keep in mind that the steeper the slope you build on, the more youll have to dig out/build up to make your shed foundation level. A gentle slope is better; an almost level site is best.
Keep your shed foundation away from areas where theres been any digging/excavation in recent years. You dont want to install your foundation only to have it start settling. This is especially important if your home was recently built; make sure you dont pick a spot that was excavated during construction and just recently backfilled.
If your shed will have windows, it doesnt 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.
Heres 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 youre shed foundations, make sure you know exactly where your utility lines are. You probably wont need to dig that deep for a shed foundation, but the stakes that fasten the perimeter lumber could go deep enough to hit something. Its always better to be safe than sorry!
811 is the nationally designated phone number for requesting utility companies to mark lines on your property. Its a completely free service to you as a homeowner, so by all means, take advantage of it! Someone once said: Call 811 now so you dont have to call 911 later! Photo: Pepco
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 youre in compliance. Specifically check:
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 weve 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.
Check first with your township/municipality to see what they require. If youre buying a prefab shed, check with the shed company to see what anchoring system they offer or recommend that would meet local requirements.
This one is a no-brainer. Think about the primary use for your shed and plan accordingly. If itll be for your garden tools, put it nearthe garden! If its for household items, put it close to the back door. You get the idea
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 homean extra plus if you hope to sell your property sometime in the near future.
If youre a seasoned DIYer, youll 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 dont own them (or have a friend who does), you can rent them by the day at a fairly reasonable rate. Photos: Home Depot
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 dont 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!
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.
To really get your gravel shed foundation compacted well, theres 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.
Once you have the tools collected, its time to gather (or plan for) the materials youll 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 youll need to buy.
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 44 or larger and make sure that its not only pressure-treated, but also rated GC (for ground contact). Here at Site Preparations LLC, we use 46 GC pressure-treated lumber for all the gravel shed foundations we install.
Youll 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, youll 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
Youll 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
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
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.
This article is all about GRAVEL shed foundations, but its important to note that were actually referring to CRUSHED STONE. Real gravel (also referred to as river stone) is smooth and rounded on the edges.
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: Eds Landscaping Supply Inc.
Crushed stone comes in a variety of sizes and types. The best type of crushed stone for a gravel shed foundation is clean, sometimes also referred to as clean stone, washed or #57, depending on the supplier. clean is stone that has been screened through a square screen and has been washed to remove stone dust and other residues.
Its 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 clean stone is the best for a gravel shed foundation.
Youll 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 youll 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.
Its important that the outside edges of your gravel foundation be about 2 longer and wider than the dimensions of your shed. Thats because you should have at least 12 of extra space on each side of your shed to allow for water to drain off properly and protect the bottom of your shed.
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, youll 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 its close before you start digging.
Alternatively, you can use stakes and string to mark the edges. If you do that, its a good idea to keep the stakes out a couple feet from the actual corners (as shown in the diagram) so they dont become loose during digging.
A laser level or laser transit with a receiver is the simplest way to level your site and only requires one person. First, youll 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 youre not familiar with using a laser level, you might want to watch a video demo like this one or this one.
This is another simple way to check for level. If you have stakes set up at each corner, simply tie a piece of nylon masons 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 its level. Then, simply measure down from the string at each corner to find the difference in height between those two points.
This method works well if your shed foundation will be relatively small. Find a very straight piece of lumber (a 24 or 26 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.
Often, steps 5 and 6 will take place simultaneously. Once you have the site marked off, its 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. Its 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 downhill side, youll 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, youll 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 youre 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.
Youll 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 its level. If its 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.
If youre 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 youll start the third course).
If youre 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, youll 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. Its 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.
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. (Dont ask us where the name came from!) In this design, the deadman (deadmen if theres 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, theyre 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.
Pound 2 rebar stakes through the perimeter and into the ground. If you didnt 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.
Now that the perimeter is in place, you can finish removing the topsoil and excavate any remaining high spots inside the foundation. Its 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 youre using 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 wont sink over time. Use a tamper if necessary. If youre using heavy equipment, like a mini skid steer, you can use its weight to help pack the dirt.
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.
Pull the construction fabric tight over the dirt as you work your way around the perimeter of the shed foundation. If you added bracing inside your foundation you may need to slit the fabric to fit around it.
Finally, its 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, its 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 24 or 26 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.
Weve 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 whats already tamped in the center.
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.
Hi Herbert, Thanks for your comment! Its important that you get pressure-treated lumber thats rated for ground contact. That being said, it wont rot any faster than a fence, deck, or other structure with posts in the ground.
Hi Matt, Most prefab sheds that include electric have the conduit running out the side above ground, so it often doesnt need to go through the foundation at all. In cases where the conduit does go through the shed foundation, we use an L-shaped piece of conduit with the ends taped off, long enough that the end extends at least 5 above the completed pad. After excavation, we place the conduit so one end is at the proper location relative to the shed and the other exits beneath the lumber perimeter. You can see a photo of a completed pad with conduit here: https://www.siteprep.com/wp-content/uploads/Unorganized/20190404_132334.jpg Hope thats helpful!
This is the best info Ive been able to find online. Thank you. Ive placed the 4x6s. My grade is on a slight slope. If I place the gravel now, one side will be 5 deep and the lower side will be 10 deep. Will that be a problem or should dig out the high side and place the fill on the lower side to produce a constant depth of approximately 7.5?
Hi Robert, its fine the way you have it, as long as theres at least 4 across the entire pad. 3/4 clean stone packs tightly, even when 12-24 deep. Its better to leave the soil undisturbed, as backfill will have a greater chance of settling than the stone itself.
Hi Mike, we tie our corners together with screws and put our first rebar stake in about 12-24 from the corner. It probably wouldnt hurt to add one in the corner, but not really necessary. In fact, you wont get quite the same strength with a hole drilled that close to the end of the lumberits prone to weaken as the lumber ages over the years.
When you start at the lowest point w the timber,and stack each post, do you follow through With each post (on both sides)all the way to the highest point in the ground, or do you cut sections, stacking to the highest point only going as far as the ground allows to the highest point?
Hi Allan, Im not 100% sure what youre asking, but Ill do my best to answer! If you are building the foundation up to level (if the shed door will be at the highest point in the ground) and the first course of lumber moves below ground level as you work toward the highest point, you can simply begin a new course of lumber. If you are digging the foundation out to level (if the shed door will be at the lowest point in the ground) you will need to continue the first course of lumber around the entire foundation. Hope that makes sense!
Hi Murray, we often dig down 2-4 on a level site. That a) leaves a lower step-up to get into your shed and b) eliminates that top layer of topsoil that might be more likely to settle over time. That being said, you may be fine going right over the buzzed lawn if you have a high-quality geotextile. Make sure youre able to get the crushed stone at least 4 deep inside the foundation!
Great video and very well done! Is it fine to notch the timber ends instead of using butt joints? Also, is it ever wise to put gravel or a stone block under the timbers for leveling and drainage or is solid dirt is all you need?
Hi Warren, butt joints on the corners of the shed foundation are fine, but notching them shouldnt hurt if you have the time and expertise to do it! Solid dirt is really all you need under the timber, assuming you remove the top few inches of topsoil.
Terrific vlog. Question: 18 months ago we stripped the topsoil and had a DG (decomposed granite) landscape installed. They dug out 4-5 of soil, installed 2 of 2-2.5 gravel, 2 of 3/8 clean gravel, and topped with DG. Now Id love to have a wooden shed installed. Hubby says if installed directly on top, itll sink. I think that its weight distribution over the gravel/DG substrate will support it just fine. Were in SoCal, and get very little rain. Thoughts?
Hi JJ, We dont really work with DG, plus were on the east coast where the climate is quite a bit different, so its hard for us to give a definitive answer. That being said, we really dont like putting sheds on bases with stone smaller than 1/2 as it doesnt lock together as tightly and can be more prone to shifting over time. If you want a compromise to firm your landscaping up a bit, you could think about removing just the DG and 3/8 stone and adding several inches of 3/4 clean over the larger gravel base. As you mentioned, it is a different climate, so we cant say for sureand we definitely arent trying to take sides between you and the husband! ;D Hope these ideas are helpful in your discussions. Good luck!
Hi, I live near salt lake city, Utah where frost heave could be an issue, but would rather do a gravel base for a 1010 shed if its possible. Any thoughts? There are basically no requirements to make things up to code when I checked locally since they dont regulate anything less than 200 sq ft. Just dont want my shed to get too lopsided and not be able to open the door
Hi Trent, we build many/most of our shed foundations in frost-prone areas (PA, NJ, NY, MD, etc) and have found this foundation style to quite durable in both hot and cold conditions. In our opinion, it should not be an issue!
Site Prep crew Exceptional content with fantastic detail. Cant thank you enough for sharing your expertise with all us desperate DIYers these days! Im curious about a couple of things. I have a somewhat gradual sloping grade.. Thinking roughly 8-12 total that I intend to excavate maybe no more than a 3rd or so and take the combination approach, where I build up a little and dig out. The reason for this is because I would prefer not to be dependent on the current grade and surrounding swell in any way, thus I figured it most beneficial to be off grade and off slope. If I can better explain what Im envisioning, an example you previously posted is the closest Ive seen to what I have in mind > [Link deleted] All that aside- I have a novice question of joining your butts to extend and reach length for a single-side of your perimeter, I dont see where you speak to this in your guide and photos would suggest youre literally just butting the two timber ends and presumably using your 4 screws drilled at an angle to attach and extend (as if one solid length in lumber) Is this accurate? Would you had any thoughts on whether to also affix using something like the Simpson Strong Tie HRS416Z Straps? Next question, in your example photo I relinked above, it looks like you installed a few inward facing deadmen braces in the front despite being such a short wall, am I seeing that right and if so, is it because its exposed and theres no outward facing reinforcement behind? Curious if I should consider doing the same.. As a final two questions, any thoughts on lining the 2-4 trench for the first course with the stabilization fabric? Curious if it could improve longevity and increase age against rot. Lastly, I just wanted to confirm you would not stack these courses in the traditional way of a retaining wall, in other words there is no need to stagger or offset each course beyond the last as you build up? Thanks again!
Hi Jimmy, Glad you found the content helpful! Those are several good questions; well take them one by one. (By the way, it seems the link you shared was removed somehow, so we werent able to see which job you were referring to.) 1. Lumber butt joints Youre correct, we usually use 4 galvanized screws at an angle to join the ends of the lumber together. Plus, the rebar stakes also help to keep them in place. The Simpson strong-ties you refer to might be overkill but certainly wont hurt if you do decide to add them. 2. Bracing We usually add bracing on any walls over 16. With a deadman brace, you always add it to the inside of the exposed wall. The exact bracing scheme varies with each site; you can see examples of different bracing layouts here and here. 3. Adding fabric under the perimeter The stabilization fabric we use is porous, so it wont do much to protect the lumber from moisture. Again, its probably overkill but wont hurt if you decide to add it under the lumber. 4. Offset courses of lumber We actually do offset each course of lumber, though only by a fraction of an inch on each course. If you offset them by too much, it will cause issues when you go to drill and stake the perimeter. Heres one example where its a bit easier to see the combined offset on a higher wall. Hope those answers are helpful! You may find it helpful to look through our job portfolio to see examples of a lot of different site/foundation configurations.
Hello, what a great post!!! I have had a Shed for 17 years and all I did was level the area, and put down pea gravel. The shed is 1210 with 44 treated posts attached to the bottom of the shed. I am assuming the shed floor is connected to the 44. I have had no problem with it. Did I get lucky? I am planning on getting my shed moved closer to the house and wondering if I should build the foundation. What is your opinion? Thank you
Hi Mark, Lucky might be a strong word, but you definitely faired better than some folks do! A good foundation makes the biggest difference as sheds become older. With your shed being 17 years old now, you may want to put a more durable foundation under it when you move it. Hope the shed moving project goes well!
Hi there, Great article! Thank you for posting. I wish I would have stumbled across this sooner but I had not originally planned on doing just a gravel base to begin with. I was considering adding a concrete top layer to it. But, Ive already constructed what I hope is a sturdy gravel base but just wanted some reassurance, if possible. As after reading your article, I think it will do just fine. I used concrete blocks for the perimeter (laid them down on a bed of gravel as well to help with leveling and prevent any shifting) and dug the interior to a 4 inch depth and filled it with the gravel you mentioned. I also used rebar along the perimeter and concreted it in. However, I had not laid any landscape fabric/material beforehand as the area where the base is being built was almost all dirt (and roots) to begin with. All of that was removed while digging. Will this be sturdy enough and provide the same level of support you mention in your post? I started this last fall and I let it settle over the winter and it has held up quite well. I appreciate any feedback you can provide. Thank you!
Hi Zach, From your description, it sounds like you should be fine! The landscaping fabric gives an extra level of stability, so we include it as a standard part of all shed foundations we install (as of the past several years). However, there are plenty of good pads out there that dont include it. Best wishes!
Hi Layne, we dont specialize in house foundations, so its hard for us to give a specific recommendation. Do keep in mind that if the lean-to is attached to the house, you want to make sure its foundation wont move separately from the foundation of the house. This foundation would be fine for a free-standing lean-to shed (assuming it includes a pre-built wooden floor). Sorry that we cant give more specific advice on your scenario!
Very useful information. I have a quick question. You say add the rebar once your perimeter is complete or 3 high. I want it to sit flush with the ground, can I just add one 46 post and call it good, or do I need to have it at least 3 post high?
I really like your detailed project info on the gravel shed foundation. I could not find 4 in. x 6 in. x 8 ft. #2 Ground pressure treated wood in my area; so, can I used 44 or what other size would you recommend? Is it also mandatory to clear the grass instead of just laying the landscape fabric and putting the 3/4 gravel on it? Im just setting up an 810 shed.
Hi Ray, we usually upgrade to 66 lumber rather than downgrading to 44. Youll want to have at least 4 of gravel, so 4x4s will be cutting it a little tight in that regard. The top few inches of soil and grass are the most prone to settling after the shed is in place, so wed recommend removing them if at all possible.
Great article and video! I have a question regarding the combination of concrete piers and gravel. I assume the perimeter is built and then the holes are dug for the piers. I assume you all have to use sonotubes to get the piers to the final height that the gravel will be, correct? Does rebar get staked into the ground of the pier holes prior to pouring? What diameter of pier hole?
Hey thanks for the awesome article and video. If my gravel pad is on decently flat ground, do I need to be concerned about drainage? Well the ground fabric allow for any water that accumulates to drain into the ground? Thanks for the help!
Hi Caleb, We recommend using a permeable stabilization fabric. So unless water is already puddling in that location, the 3/4 clean stone and permeable fabric will allow water to drain straight through the shed foundation as it would on regular soil. Hope that helps!
Hi Donnie, Youre correct that Sonotubes are the way to go for pouring concrete shed footer piers. We recommend piers that are 12 or 16 in diameter for most sheds (larger piers for larger sheds). As far as reinforcement in the pier, its not generally necessary; if a specific township requires it, we will install rebar cages before pouring the concrete. Hope that helps!
Great information Got a question. My new shed is a post and beam type which is supported by a two 6X6 skids mounted 16 inches in from the out side perimeter of the sides of the shed. My question is, do I have to cover the entire area of the shed with stone beneath the shed? Or can I place, say two stone trenches of stone, say 30 inches wide beneath each skid for the foundation? The floor of the shed is 2X6 with 3/4 plywood. The shed is 14X20.
Hi George, Thats not exactly how we install our shed foundations, so its hard to make a definite recommendation. Do make sure that every part of the shed thats in direct contact with the ground has a firm, level, and well-drained base to rest on! If you do try two stone trenches, let us know how they turn out
Hi, this is easily one of the best resources that Ive come across and my wife and I have found it very useful, thanks! Given that milled and treated lumber has trebled in price in the past six months, Im curious about alternatives to wood for the perimeter. Is a row of standard cinderblocks, staked with rebar, a viable alternative to ground contact 4x6s? If so, would it make sense to add concrete mix below and around the cinderblocks to minimize risk of outward movement? For my project, cinderblocks, concrete and extra rebar would cost ~$110, while PT GC lumber option would run ~$600. Id hate to be penny wise and pound foolish though. Thanks again!
Hi Chris, It mainly depends on the slope of your site. If youre dealing with an area thats less than 8-10 off level, you should be fine with blocks. Just make sure to stake them well and not leave any large gaps where the stone can escape. If its a more sloped area, youll need to be concerned with reinforcing any built-up walls; with lumber perimeters, we recommend deadman bracing. Youll need to find a comparable alternative if youre using block. Hope that helps!
I am using your How to Build a Gravel Foundation for a 10 x 12 Shed. A few quick questions: 1) Can only find 2.5 x 100 stabilization fabric in my area. Do I need to tape the the stripes together before adding the gravel? 2) What is the best bit size for drilling holes for the 1/2 rebar, 1/2 or 5/8? 3) My lowest corner is 10 inches from level. Using two courses of 4 x 6s, I will not meet the 2-4 dig out requirement . Do I need a third course? If so, what size course would be recommended. Appreciate your help. You have a great site. WELL DONE!
Hi Michael, 1. You shouldnt need to tape the strips togetherif possible, you may want to overlap them slightly before adding the gravel. 2. As mentioned in the article, we recommend a 1/2 auger bit, at least 18 long. That will keep the stakes nice and tight when you pound them in. 3. If you need to add a third course, it may only need to extend partway around the pad. You can see examples here and here, as well as in our portfolio of completed foundation projects.
Hi, I dont think Ive ever posted a comment for anything on the internet, but I felt compelled to write and thank you for the very detailed instruction to build a shed foundation. I followed it step by step and couldnt be happier with the outcome. Im very grateful for the help, thank you!
Hi Jason, It depends on how sloped your site is. If the ground is fairly level, you may only need one course of lumber. You can see examples of a lot of different foundations in our site preparation project portfolio.
Hi, Site Prep folks! Thanks for the detailed, comprehensive instructions on building a gravel foundation. This undoubtedly saved me a lot of future headaches! I have a specific materials question for you: For the crushed stone, is the 3/4 size critical, or would 1-1/2 (clean) work equally or nearly as well? For some reason, Im having a very hard time finding 3/4 clean here in western Oregon, but 1-1/2 is easy to come by.
Hi , I am looking forward to building a foundation for a small 20 ft container home and wondering if your gravel foundation will be better than concrete one. Thank you for the great content it helps me to figure out the slope and drainage!
This was so helpful and Ive watched the video so many times and shared with others. I have a few questions Ive been struggling with. 1. My carpenter suggested we use 2 inch of Road Bond place the 46 on the Road Bond compacted. Then place the 6 inch of the 3/4 stone ( the local guy has 3/4 lime stone) is that what I want? and give me your thoughts of the Road bond compacted or should i just go with the 3/4 lime stone 2 inches then 46 and then 6 of lime stone?
2. I went to our Menards and they had 3 options and I dont know which one to choose for fabric ( Geotexile fabric) DuraWeb nonwoven and Duraweave woven and lastly Ultra poly web. ([Link deleted]([Link deleted]
Hi Inka, You will obviously want to check any applicable local codes related to foundation requirements for your planned container home. From our perspective, though, a compacted gravel pad should work quite well, assuming the container has a built-in floor. Good luck with your project!
Hi Chris, Glad you found this helpful! To answer your questions: 1. Adding Road Bond (or crusher run stone) under the perimeter isnt really necessary. However, it wont hurt anything if you choose to do it, though you may want to dig down a bit further so it doesnt lift your perimeter up too high. 2. The DuraWeb is probably your best option there. 3. Not 100% sure what type of shed youre getting, but it sounds like its being built on-site. Most of the shed foundations we build are for prefab sheds, which typically include 44 or 46 pressure-treated runners below the floor joists as a standard part of their construction. If thats what your carpenter is referring to, wed definitely recommend that. Do make sure the runners are fastened to the joists, though. Hope that helps! If it does and you have a minute to spare, feel free to leave us a Google review here.
We are moving our current shed that is all rotted on the bottom and moving it to the pad. We are going to rebuild the base and joist and then move it to the pad. We are going to bury the 46 runners into the 3/4 stone and leave just a inch or too exposed so the joist can rest on that 46 runner instead of the stone. I hope that is the right way or a good way of doing it. Thank you so much seriously wish you guys were close so i could use you to do our base. Have a great day and look forward to all the feedback. Wish I could leave 10 google reviews.
Hi Chris, Sorry we missed the question on stone type. 3/4 washed limestone is what we use. The reason we used washed stone is for better drainage; Road Bond/crusher run/#57 stone that still has the dust with it tends to pack extremely tight and can slow water from draining away from your building, which is one of the main reasons to choose a stone pad in the first place. Duraweb and Duraweave are both commercial-grade stabilization fabrics. We recommended the DuraWeb since its near the Duraweave in terms of strength, with greater permeability (from what we can tell without seeing it in person). The Ultra Polyweb is a much thinner fabric and we dont think its durable enough for this use. Hopefully that answers the additional questions!
We have subterranean termites in our area any wood that touches the dirt is eventually eaten away. Will Ground Contact lumber prevent that or do I need to go with composite decking-type material or metal?
Hi Nolene, Pressure-treated woodis infused with chemical preservatives to help protect the material against rotting and insects. In general, termites wont touch ground contact pressure-treated wood. So while ground contact pressure-treated wood is not technically termite-proof, it is considered termite-resistant. We have not seen termite issues in shed foundations using ground contact pressure-treated wood. Hope thats helpful!Get in Touch with Mechanic