A backyard shed is one of the best investments you can make to increase both the value and the usefulness of your property. But before it arrives at your property (or you build it) you obviously want to think about the proper way to do ground preparation for a shed!
Once you’ve determined whether or not you need a foundation for your shed and which of the shed foundations to use, preparing the ground for a shed is not an incredibly complex job. Good tools, quality materials, and proper planning will make the job painless and efficient. (Step-by-step instructions for building a gravel shed foundation can also be useful!)
However, there are some common mistakes you’ll want to avoid as you work on the project. If you’re planning to hire a site preparation contractor to install your shed base, you’ll also want to make sure that they’re qualified for the job and aware of these issues. Here are 7 mistakes not to make:
Table of Contents
1. Placing Your Shed Too Close To Property Lines
While this is technically not part of the actual ground preparation for your shed, it’s important to double-check where your preferred shed location falls relative to your property lines. Most townships and municipalities have specific requirements for building setbacks (distance from property lines) and you’ll want to check them before you start building.
It’s common for local regulations to require a shed to be 5-15 feet from the rear or sides of your property. For instance, Manheim Township in Lancaster County, PA requires a minimum of 5 feet setback from the side/rear property lines.
It’s best to check directly with your local zoning office to see what, if any, requirements affect you. If your property is part of a homeowners’ association, they may have additional requirements and if there are any easements on your property (such as overhead utility lines) you’ll want to take those into account as well. You can read more about choosing the ideal location for a shed here.
2. Preparing A Shed Site On Low-Lying Ground
If there’s anything you don’t want, it’s a flooded shed! If you have a choice, you will definitely want to avoid placing your shed in any swampy or low-lying areas of your property. Look for a high, well-drained spot and do the ground preparation for your shed there.
Building a shed in a wet area can have several negative effects, even if you can keep your shed from flooding. For one, excessive moisture will tend to make your shed deteriorate faster as it promotes rot. In addition, mold and mildew love to grow on buildings in wet areas. Finally, maneuvering any lawn equipment becomes much more difficult when the ground is soft.
3. Not Leveling The Ground Properly Beneath Your Shed
This is probably obvious, but it bears repeating. One of the quickest ways to cause issues in your shed is to simply put it in the backyard without first making sure the spot you’ve chosen is level!
If a shed is off-level, it can put strain on the structure which the framing was not designed for. Also, if the slope is too steep, anything with wheels will find a way to roll around in the shed! You can read more about how to level the ground for your shed here. (Leveling is important for other site preparation projects as well, such as preparing a gravel hot tub base or a gravel area around a fire pit.)
4. Using Only Concrete Blocks For Ground Prep Under Your Shed
There are a lot of people who will suggest placing your shed on concrete blocks, but in the long run this is probably not the best ground preparation for a shed.
One of the biggest reasons to not use concrete blocks under a shed is the fact that the shed will not be supported evenly. Even if you are able to perfectly level all the blocks (which is difficult) when you first place your shed, as the years go by, the blocks will tend to settle at different rates. This can put unnecessary strain on the shed’s framing, causing it to show its age much faster.
Eventually, you might end up with a shed that is listing to one side. Worse, the uneven strain on the shed’s frame can cause windows and doors to bind, preventing easy opening and closing.
In addition, sheds on blocks offer a perfect place for critters to burrow. Once they’re underneath the shed, they’re much more likely to cause damage to the structure from below. We have an entire article about the use of concrete blocks under sheds here.
As an alternative to concrete blocks, a gravel foundation is one of the most economical and durable ways to prepare the ground for a shed. It will support the entire shed evenly, keep the bottom of your shed well drained, and discourage animals from nesting beneath your building. Here are three more pitfalls to avoid when using gravel for you shed base…
5. Not Preparing Enough Extra Space Around Your Shed
If you’re preparing ground for a 10×12 shed, you’ll need a 10×12 foundation, right? Well, not exactly. It’s important to plan your foundation with some extra space around your shed.
Generally speaking, your shed foundation should allow for at least 12” extra on each side of the building itself. So, if your shed will be 10×12, your gravel foundation should be 12×14.
Allowing 12” on all sides of your shed, accomplishes a couple of things:
First, it reduces rainwater dripping off the roof from splashing up against the sides of your shed. This will keep the sides of your shed cleaner and help them last longer.
Second, extra gravel will help keep grass and weeds from growing along the sides of your shed. Grass can trap moisture around the base of your building, helping it to deteriorate faster. Also, you run the risk of scratching and scuffing the sides of your shed as you trim the grass around it every week. You can read about choosing the correct size of shed foundation here.
6. Doing Ground Preparation For Your Shed Without Landscape Fabric
Gravel alone might not be enough to keep all the grass and weeds away from your shed. It’s a good idea to add landscape fabric as part of the ground prep for your shed. But what exactly is landscape fabric?
Landscape fabric (also known as weed barrier) is a fabric, generally made from polypropylene fibers that is placed under flower beds, gardens, and other landscaping to prevent unwanted plants from sprouting up through the soil.
By placing a fabric weed barrier over the soil before adding the gravel to your shed foundation, you almost completely eliminate the chances of any weeds sprouting up around your building. Additionally, the fabric helps separate the gravel from the soil beneath it, adding extra stability to the finished shed base.
At Site Prep, we use commercial grade landscape fabric in every shed ground prep job we do.
The barrier product we use is actually the same type of heavy duty fabric used in road construction to prevent potholes! It adds a lot of stability and resilience to the gravel foundations we create and we won’t build a shed pad without it.
7. Preparing Ground For A Shed Without Adding A Perimeter
A lot of landscapers or DIYers miss this important step in the shed site prep process. It might be tempting to just clear a spot of grass, lay down some weed barrier, spread a pile of gravel around, and call it good enough. Don’t forget the perimeter, though!
A solid wooden perimeter helps to contain the soil and gravel for your shed foundation, so it won’t be spread around and work its way into the lawn as the years go by. It’s especially important if you’re planning to build your shed on a spot that’s off-level. In that case, your perimeter can also double as a retaining wall.
Choose a high-quality, pressure-treated wood for this job. Make sure the lumber you select is rated GC (ground-contact) since it will be exposed to soil moisture for years to come. In addition to screwing the perimeter together, the corners of the lumber should be drilled through and staked down with rebar to keep it anchored to the ground. At Site Prep, we use 4x6s for most applications (6x6s under some circumstances).
Let’s Do It
And there you have it! Plan ahead, avoid these mistakes, and you’ll be well on your to having a long-lasting shed foundation!
If the project seems a little bigger than something you want to tackle yourself, you always have the option of working with a professional site preparation contractor to do the ground preparation for your shed (we also offer residential and commercial excavation services). Site Prep offers shed pads, garage foundations, and general site prep throughout Pennsylvania, New York, New Jersey, Delaware, Maryland and beyond. Give us details on your shed project and we’ll be glad to provide a free quote for ground prep!
Very helpful. Thanks. What brand or thickness of landscape fabric do you use. It has to be porous so water does not collect , right.
Hi John, we buy commercial-grade stabilization fabric, such as what is used in road construction. Similar to this: https://www.usfabricsinc.com/products/us-200/. You may be able to find something similar at Home Depot, etc.
We actually have a full tutorial article on how to install a shed foundation that gives a full list of materials needed.
Hope that helps!
This article was helpful, thanks!
Glad to hear that, Rich!
Hi. My shed site is uneven with roots from nearby small trees visible on the surface. Shall I raise the level of the base well above the roots using a pressure treated perimeter and fill it with gravel? I’m concerned the roots may cause movement and collapse the gravel – is that a risk or unlikely? The base dimensions is approx. 8′ x 8′. Thanks
Hi Glenn,
We’ve been notching the perimeter lumber out around tree roots in situations where we encounter them. So far, that’s worked well for us. There’s probably more risk of the tree roots moving the lumber than the gravel…just something to consider.
Good luck with your project!
I live by the lake . Water has not been an issue for 30 years
Last shed was 30 years old in on spot. The last 2 years water has been high and we have flooded and water sits in that corner of yard now. If I want to build up before I replace shed do I only use cloth and gravel or should I add more dirt first?
I was going to fill in than add about 4 to 6 inches of the small compacting/ screening gravel
Will this be okay?
Hi, I am building a shed on an old leech field.
Q1: After I dig out my site, what is recommended depth, 4″, 6″, ?
Q2: It seems to me that it might be useful to slope my digging to one corner, to allow for overflow water to be drained out from under the shed. I live on a lot of clay…
Q3: What is the best way to compact/consolidate the soil after I dig out to prevent excessive settling? The plate compactor and jumping jack compactors seem a little.. wimpy?
Appreciate your time!
Hi Verna,
If you’re building your site up, keep in mind that gravel settles less than dirt. We’ve installed built-up pads with gravel several feet deep! We recommend using “3/4″ clean” gravel as that will allow the best drainage and will lock together to prevent settling. We actually have a full shed foundation installation guide here: https://www.siteprep.com/how-to-install-a-gravel-shed-foundation/
Hope that is helpful!
Hi Fred,
First off, it is a bit risky to build on a drainage field…not something we generally recommend. If that’s your only option, we’d recommend only digging down a few inches (4″ or less)…undisturbed soil will settle the least.
There’s no need to slope the site unless water was pooling in that area previously, in which case you’d want to come up with a drainage plan before you build. The gravel pad is permeable, so water will soak straight through as it would otherwise.
As far as compaction, we try to disturb the soil as little as possible; we also use the weight of our skid steer to compact it before adding gravel.
We have an entire how-to guide here, which you may find helpful: https://www.siteprep.com/how-to-install-a-gravel-shed-foundation/
Good luck!
How does one build the foundation on soft soil, when that is the only location zoning allows?
Hi there- I have dug a shed prep space and it is ready for landscape fabric and gravel, but since we’ve had a lot of rain lately, the dirt is a bit on the looser, muddier side… no puddles, but definitely looser in spots… so I need to wait until the ground dries out more before laying the fabric and gravel, or does the weight of the fabric and gravel help dry it out? Thanks!
Hi VW,
You’ll want to excavate down until you reach firm soil. If necessary, you may need to add concrete footers as well; you can see some examples of that here and here.
Hi Gregory,
It’s ideal to have the ground as firm as possible. To be honest, we usually do the excavation and lay the fabric and stone on the same day to avoid that issue as much as possible. That being said, assuming you’ve removed any loose topsoil it should be fine if the ground is a bit damp. And of course, make sure to tamp the crushed stone well after adding it. Hope that’s helpful!
Putting in my first shed, zero experience/knowledge, found this article during a Google search, I’m pretty sure I would have made several of the “common” mistakes listed (blocks, no extra space, no fabric, no perimeter). Thanks a ton for posting helpful information like this for knuckleheads like me!
You’re welcome, Caleb! We also have a free step-by-step shed foundation installation guide if that’s useful to you. Good luck!
Hi,
I’ve got a 30 yr old shed on sloped ground which wasn’t prepped properly. And you guessed it, the ground has settled, and every time it rains I’ve got two inches of water underneath.
I can’t afford to have it moved and a new pad installed.
The corners have been jacked and leveled and raised with more 8x16x1 blocks.
Still there’s water.
I’m thinking of pulling the floor myself and auging holes and filling them with gravel.
Then spreading more gravel underneath.
Do you think that would work?
Hi Ali,
That may work…it’s a bit different approach than what we usually use, so we can’t vouch for it specifically. You may also want to see if there’s any way you can divert water away from the shed. Good luck with the project!
Wondering if it would be ok to substitute the landscape fabric with a polyethylene tarp?
Hi Joann,
We wouldn’t recommend it due to permeability issues. The stabilization fabric we recommend allows water to drain through the foundation and into the ground. A tarp will trap water in the foundation beneath your shed and will likely shorten the lifespan of the lumber in your shed floor and in the foundation perimeter.
We’re having our first ever backyard shed delivered late September. It will be 12′ X 16′ and have a little cottage look but, it’s specifically to hold pool equipment. Our pool currently has all of the equipment visible and we don’t like that look. The floor of the shed is wood and the joists are wood too. I’ve hired a landscape company near me to prep the location but they did not suggest the wooden perimeter around the gravel. The area has a very slight slope and is heavily wooded. Over 100 trees were removed to create space for the in-ground pool and concrete sun deck surround. I want the shed to sit back into the trees. Based on my description do you have any suggestions? I have approximately one month to do what you suggest.
Is it advisable to use wood chips as a foundation for a shed?
Hi Richard,
We often install these foundations in wooded areas; the only downside is the pain of occasionally dealing with roots/stumps during installation. We recommend the perimeter, especially on a slope, as the gravel will tend to wash or drift away over time, causing your shed to sink or list to one side. Our recommendation would be to invest in a perimeter for your shed foundation in order to protect the longevity of your shed. Good luck with the project!
Hi Dale,
Wood chips won’t pack tight enough to support a shed properly. Plus, they will settle and eventually disappear as they decompose, and it will be hard to replace them under your building. Hope that’s helpful!
Hi,
Very good information, thank you! We recently had a shed installed by a local company who prepared the area with gravel that was just dumped on the existing grass on our lawn. Even though it’s pretty deep I’m concerned about future weeds etc. I asked about the matting and they assured me nothing would grow through….. this conversation took place as we were standing there watching the shed move across our lawn. Not only that but they put our shed on concrete blocks! Our shed was high enough on the 10 inch rock bed they dumped now it’s even higher and trying to drive a lawn tractor in and out on the ramp is now risky.
We were told our town required the blocks…..we’re going to remove them and let it sit on the stone and just hope for the best. The shed cost us 7,000. ( cedar) when all said and done. Is it me or does this whole set up seem ridiculous. Thank you and Looking forward to your response 🙂
Hi Valentina,
Sorry to hear about your sub-par experience! We definitely recommend against using concrete blocks for a shed foundation. Municipalities often have requirements for shed anchoring and frost-proofing, but concrete blocks alone don’t meet either of those requirements. We always excavate for our shed foundations so that the height difference is as small as possible.
It might be a little late now, but we do have this guide to installing a gravel shed foundation if it’s helpful at all. Good luck!
Hi Guys and Gals,
if town code says shed height cannot exceed 10ft. do we have to take into consideration the site prep area in that calculation>
Thanks
Faze
Does anyone have experience with the fabric floating or being disturbed by hooves or other and becoming a nightmare to remove? I am a landscaper and find this commonly the problem even under 4 inches of rock.
Hi Faisal,
We would assume not, but it would be best to check with your local inspector or code compliance department to see how they typically interpret their own laws. Good luck with the project!
Hi Jaceymae,
That’s not something we’ve experienced. Typically a shed is pretty stationary :), so it would seem to be more durable here than in a high traffic area. We’d be interested to hear feedback from others, though.
Do you service Northern California?
If not, do you know a company that does? I’m planning on building an large art studio in the spring. In Mount Shasta, where I reside, I get all 4 seasons.
Hi Connie,
Unfortunately, we only work on the east coast as of now. We don’t know any specific companies doing shed foundations out there, but some landscaping companies can do this kind of work. We have a complete guide to building a gravel shed foundation which you can follow to do the project yourself or show to a contractor to give them an idea of what you want to have done. Best wishes!
Hello,
We did a crushed stone base for our shed and the shed is level but the pad ended up not being completely flat. The gravel supports the perimeter skids but the skids stop touching the ground once you get towards the middle of the shed. Therefore the shed is not supported evenly, mostly just the outsides. Will this be a problem in the future? Should I Jack up a corner and add more loose crushed stone, although I won’t be able to compact it. Shed is 10×20
Thanks
Hi Alex,
Ideally, as you know, you’d want all parts of the shed supported evenly. At this point, you can either jack the shed up now and add some stone, or just wait and see if the shed sags at all. If you start to notice issues with doors or windows binding, you can always jack the shed up at that point and re-level the pad to correct the issue. Hope that makes sense!
Hi. Can i use a dry stack stone retaining wall up to 2 feet high (on the down slope side) as the border instead of 4x6s?
Thanks
Hi Greg,
We don’t use stone retaining walls, so we can’t give you a definite recommendation that way. You will want to keep in mind any necessary bracing to protect the integrity of the pad over time. Best wishes with your project!
Hi, thanks so much for this helpful article. I am building a shed and want to place it over a french drain and water line. I will use gravel as a base, and place the skids so they are no over either line but running parallel to them. Do you think that will be an issue?
Hi Doug,
If you have any options for placing your shed somewhere besides over your drain, it might not be a bad idea to consider. However, if the water line and drain are both installed and covered properly, it shouldn’t matter if the shed skids are running parallel or perpendicular to them. Be sure to check out our shed foundation installation guide for more specific recommendations on that part of the project. Best wishes!
Hello, I have an 8 x 12 shed with dirt under it sitting on blocks. I am rehabbing it from termite damage. the problem is the back of the shed sits about 3′ from my wood fence and slopes down. so apparently the dirt and leaves built up behind and under the shed, contacted the wood and that is how the termites got in. Should I put gravel under my shed? I can put gravel as a perimeter around the 3 sides but I dont know what to do about the back. It only sits about 3 inches from the ground. Should I put a treated 2×4 across the back? Thanks you for your help. your site is great and I have learned a lot reading the comments.
Greetings. Very helpful site, thank you! I notice that gravel bed construction always involves creation of a perimeter using wood (usually anchored, etc). Can a concrete (rebar-enforced) perimeter be used as well, or does the porous nature make concrete a bad material choice for the foundation perimeter?
Hi Sandy,
It would be ideal to have at least 4″ of gravel under the shed. If possible, you may want to jack up the end of the foundation so you can add crushed stone beneath it.
You can see our recommended shed foundation installation steps here. You may be able to use parts of this process to update the foundation under your existing shed. Best wishes with the project!
Hi James,
Concrete could be used as well. It’s just more expensive and time-consuming to install a reinforced concrete perimeter, which is why most folks opt for treated lumber.
Apologies for the second post; please disregard the first. Corrected version:
Hello! Thank you so very much for all of the useful information on your site! I wish we could hire you here in the Pacific Northwest! We are building a shed gravel base to hold a 7×7′ resin shed on a sloped side yard. We’re looking to use retaining wall blocks to raise up the lower sides about 12″ and then edge the whole perimeter with additional blocks (all leveled to match the height of the retaining wall). We’ll then fill the interior space with 6-12″ of crushed rock. Are there any issues to be concerned about or aware of with using retaining wall blocks instead of a wooden perimeter? Thank you for your insight!
Hi Kate,
Glad you found the site helpful!
The main things we’d consider:
1. Make sure the retaining wall is strong enough to support the weight of the gravel and shed pushing out on it. At 12″, it shouldn’t be a problem, but do be aware of it when building the wall.
2. Make sure the wall is tight enough to keep your gravel contained. (Not sure what type of retaining wall blocks you’re planning to use…)
Otherwise, you should be fine. Good luck!
Hello Site Prep! Wowsers! what a FANTASTIC resource 🙂 Thank you so much..
while i’m quite handy and the construction of the skid is not a problem, if i might ask a few questions to learn from the masters id be very much obliged! As we know, time spent on reconnaissance is seldom wasted 😉
i’m trying to essentially ‘do the best with what i’m working with’ and would like to know the following if you would indulge my curiosity.
A/ due to space constructions (putting between two swamp maples) the ideal 1′ perimeter each side is not feasible and the max i can get is 6″. i’m planning on a 10×10 (garden equip/mancave), so skid would be 11×11. whilst not ideal, is it acceptable?
B/ due to financial restrictions, again whilst not ideal, can you get away with 3″ of gravel? i need to buy it by the pallet so as to transport to site easily in bags. i think 1 pallet would give me 30cubic feet so pretty on the money, if i buy 2 pallets i have ALOT left over! 😉
C/ and finally…(jeepers, im sorry!) if i build on the swamp maples roots which are pretty much covering the whole garden, is that an automatic no no? they are about 90 years old and were here before the house. do you have experience with that?
Thank you so so much for any insight and advice. very best, Johnny
Hi Johnny,
Sorry for the delayed reply here! To answer your questions in order:
a. 6″ is definitely better than nothing, if you’re not able to do a full 12″ on each side.
b. 3″ is better than nothing, although we typically shoot for 4″ as a MINIMUM, meaning we do go deeper on some projects. Of course, you have to consider your wallet in the equation. 🙂
c. We try to avoid tree roots whenever possible since it can be a long-term liability to the stability of the shed pad. You have to work within the constraints you have, though.
Hope that’s at least somewhat helpful! 😀
Hello,
I have to remove an old cracked concrete slab and want a crushed stone pad for a new shed. What can I use as a border. I do have fruit vines, grapes and peach trees with veggie garden near by and was told not to use pt wood for it would leach into the soil. Any ideas for a safe border around veggies and fruits , many thanks Tina
Hi Tina,
If you’re able to find them, railroad ties are another option. Some folks also build a stone retaining wall, though that’s a bit more tricky.
We’ve actually used pressure-treated lumber to build some raised garden beds at the request of some customers. The newer ACQ-treated lumbers used nowadays don’t have the same health risks as the CCA-treated lumber sold 20+ years ago. Here’s some info from the University of Oregon on the topic. Of course, you’ll need to make the final decision based on what you’re comfortable with. Good luck!
I want to install a resin 6 x 5 shed 1 foot from my house. on a gravel base. There is a 6″ corrugated plastic gutter drain under that site about 6 inches down. Is it OK to build on top of that drain pipe or do I need to remove the drain pipe?
Hi Jeff,
It that’s the only location that works for your shed, it would probably be best to move the drain pipe. If the drain runs under the shed, there’s a risk of it destabilizing the site over time. Good luck with your project!
Hi there, I wish you were in Florida, I would hire you in a second to build the gravel pad for my shed. Alas, some questions.
1. Would recycled plastic lumber work instead of treated wood for the perimeter? It’s very heavy, strong, and durable, but I wonder about warping in the sun/heat.
2. Should the shed sit directly on the gravel? or can it be put on concrete blocks on top of the gravel? ( The shed I’m thinking about is delivered on top of a treated lumber skid that I believe stays with the shed. They usually put the whole thing (shed and skid) on top of concrete blocks. But the soil here is very sandy and I think a gravel pad is necessary.)
Thanks much for any info you can offer.
Jane
Hi Jane!
1. It’s hard for us to comment on plastic lumber without knowing exactly what type of product it is. It does seem like it should work, especially if it’s the same type of recycled poly material that’s used for decks and other outdoor applications.
2. No, concrete blocks aren’t needed. In fact, we don’t recommend them. The gravel foundation is designed for the shed to sit on directly and will support the entire shed more evenly than blocks. You can see a photo of shed skids directly on a gravel pad at the top of this article.
Hope that helps!
Firstly thank you for all this excellent info! Quick question: I’m planning a shed (for an outdoor sauna) that’s about 8×6 feet on a slight incline. We’re in a cold climate with 40 inch frost lines, I’m wondering if a 4inch deep gravel perimeter is enough to compensate for heave? Or is 6 better? We’re on very hard packed clay. It’s a pretty small structure that’ll be empty most of the time so I figure I can get away with not doing a big old concrete pad? Thanks again!
A 4 in. gravel perimeter should be fine. If you’re still a bit concerned about compensating for frost heave here are 2 options: (1) check local codes for foundation depths/footing depths (2) read these 2 articles to learn about foundation footers and foundation piers, respectively: https://www.siteprep.com/shed-footings-complete-guide/ & https://www.siteprep.com/shed-foundation-piers/.
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It really helped when you described how we’d prepare our land before installing a shed. Next month, my brother wants to add a shed to his house since his garage is running out of available space, so I think your tips will improve his project. Thanks for explaining the importance of leveling the ground when preparing your land.
We’re happy you found the information helpful!
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Hi! My husband and I bought a house that has a “mother in law shed” It seems it was just placed there. We need to do everything as if the shed was just bought, we don’t want it to get ruined by the weather because it wasn’t probably maintained by previous owners. We don’t want a falling apart shed in our backyard. My husband and I want to landscape our backyard it’s all dirt, weeds do grow around the shed. How would we go about laying down the fabric and gravel, would we have to move the entire shed? Thanks!
Yes, you would probably have to move the shed to lay down the fabric and gravel. Here’s an article that details the steps a bit more: https://www.siteprep.com/how-to-install-a-gravel-shed-foundation/
Great article! I’ve been wanting to build a shed for a while now, but I’m not sure where to start. This article has given me some great tips to follow.
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Great article! I’ve been wanting to build a shed for a while now, but I’m not sure where to start. This article has given me some great tips to follow.
Thank you! Glad to hear it’s helped you!
Hi ya.ive just had a summerhouse built and 3 sides have loads of room for me to treat it layer on in life but the 4th side is about an inch from the wall so I can’t treat it.how can I protect the side from bad weather.the wall is about 2 foot high.
Our specialty is foundations, not housing construction. We would say talk to your local contractor.
Hi, I have been using your site as a resource for my shed build. Many thanks! I am using crushed stone for my base. My plan is to lay the five 4 x 4 x 16 GC lumber on top of the stone (5″ depth – ground is solid, level and high point of my yard) and build up from there. I will have a perimeter of 4 x 4 GC lumber that will be 2′ larger than the shed all the way around (16′ x 20′ for my 12′ x 16′ shed). I have a neighbor that insists I should lay in concrete squares in the gravel under the 4 x 4 x 16 GC lumber. He suggests the 1 1/2 x 16 x 16 precast from Home Depot. I am in the south, just below Savannah and would love to hear your thoughts on this. Best wishes, Tim
I love your site as it has been very key to my project. I am building a 12 x 16 shed on a #57 stone base. The location is the highest point of my yard, firm, level and drains well. I am going to extend the stone 2 feet all the way around (16 x 20). The stone will be 5″ deep and compacted with a plate compactor. The shed will rest on five 4 x 4 x 16 GC runners. I have a neighbor that has suggested I place 1 1/2′ x 16″ x 16″ pre cast blocks under the 4 x 4 x 16’s. What are your thoughts on this?
Can you share some advice regarding a foundation for a blow molded plastic shed (similar to Rubbermaid)? The shed is 8’x10′ and includes a floor. We had a 9’x11.5′ concrete pad poured last month, but it’s neither flat nor level and we must now remediate. The elevation difference is ~5″ front to back. There is an existing 8’x10′ plastic shed on an adjoining concrete pad.
1. Can the final pad slope back at 2%? This roughly matches overall grade and minimizes fill. A level pad would sit above grade (the adjacent concrete pad) at the back of the shed.
The material cost for a Quikrete overlay is ~$500 (on top of the cost of the original pad), so we’re considering a gravel pad to save money. (Gravel is $30 a yard)
2.a. What’s the minimum recommended pad size and thickness? Entire 9’x11.5′ existing pad, 4″ thick? Even at the front where required fill is minimal?
2.b. How should the gravel be confined? Would a wood frame anchored to the concrete be appropriate?
2.c. Can the gravel be placed at 2%?
2.d. Can the gravel be hand tamped?
3. Is there a better alternative that we should consider?
Hi Aurora, please feel free to reach out to us using the provided link so that we can assist you better. Thank you.https://www.siteprep.com/get-quote/
Hi, Tim, we would fill the whole thing up with the end, we don’t typically use block underneath stone at all. Thank you.
Hi Tim, typically we lay our wood right on top of the dirt, and never had any issues, I don’t see any value in adding concrete blocks underneath the border, we’re using ground contact pressure treated lumber, which is meant to sit on the ground.
Im getting a 12×28 garage put in on a gravel foundation from you. I was wondering should i place a wire mesh or something on top of it before they place garage on top so rodents dont dig holes thru gravel?
It’s up to you. The tamped gravel will be difficult to dig into.