Site Prep and Foundation Options for Portable Sheds

Laying the Groundwork for Customer Satisfaction

A portable shed can be a significant investment for a customer. While the quality of materials and construction is very important, the shed setup is just as crucial to ensure its longevity and long-term customer satisfaction. Even the best quality shed will have a dramatically shortened lifespan if it’s installed poorly. To avoid this, a number of factors need to be taken into consideration, including site access, site prep, and choice of foundation. 

Site Access

One of the first steps in the sales process with a customer is to determine the size of the shed needed and where the shed is to be placed. If the customer wants to purchase a prefabricated shed, it needs sufficient access for delivery. If a fence or tree is in the way, for example, the customer will either need to have a plan to temporarily take down and replace the fence, have the trees removed, etc. If that’s not feasible or cost effective, then the customer will need to have the shed built on site.

Shed Placement

Many municipalities, especially in more populated areas, will have codes that state where on a property a shed may be placed, including setback requirements, which is the distance between the shed and street, property lines, other structures, etc. They may also state foundation and anchoring requirements. Even if a shed falls under the size limit for a permit, local zoning ordinances and HoAs may still have restrictions on placement. If electricity or water hookups are needed, the permit will need to allow for that and their proximity to utilities will need to be considered. And of course, the property owner should be sure to call 811 to have the area checked for underground utilities before digging. Not having all required permits in place can result in stop work orders and fines, slowing down or canceling a project along with potentially making it difficult to get approval for future projects, so customers should also have this process completed before purchasing a shed.

Once all necessary permits have been obtained, the customer and delivery company will need to verify that the path from the property access point, such as a driveway or alley, has enough maneuvering space for the shed to be moved into place and that the access path is clear to avoid extra work or delays when delivering the shed. Additionally, when planning the location of a shed, especially in a small yard, the customer will need to plan for adequate space for clearance on all four sides of the shed to allow room for setup. 

Anthony Mitchell, president of Outdoor Options (OutdoorOptions.com) offered these helpful tips to guide customers: “Think about gates, fences, and trees. Also think about overhead obstacles like power lines or low hanging limbs. Tight spots and turns are fine. We can handle hills and slopes but some retaining walls will require additional equipment. Mark any underground obstacles like septic tanks or old stumps and water or electric lines.” He added, “If you are hoping to cover up your dog’s favorite bathroom paradise, then please give it one last clean up before getting your new structure delivered. If you have to do some clearing and brush burning to get your building where you want it, make sure any ash is removed and there are no hot spots left under your new structure. And finally, “If you poured a slab, please take the form boards off so we can get a good tight fit.”

A. Crushed stone, commonly called “gravel,” is relatively inexpensive and simple to install, can be used to level out uneven ground, and provides good drainage. According to Site Prep (siteprep.com), gravel pads are the best choice for most situations. Many shed manufacturers recommend a gravel base and some manufacturer warranties require it.

B. Pavers are relatively inexpensive and easy to place. They don’t require a treated wood frame to hold them in place, and they allow water drainage. They will shift over time, however, reducing shed stability and structural integrity. They’re in direct contact with the shed, which limits air flow underneath, allowing shed base rot to occur faster, and creates easier access to rodents and other animals.

C. Many municipalities, especially in more populated areas, have codes that state where on a property a shed may be placed, including setback requirements, which is the distance between the shed and street, property lines, other structures, etc. They may also state foundation and anchoring requirements. Even if a shed falls under the size limit for a permit, local zoning ordinances and HoAs may still have restrictions on placement. 

Jeannie Kontis of Fox Country Sheds said, “Very often, customers underestimate the role of a proper foundation. We believe it is our job to explain to them the importance of proper site preparation for the long-term durability of their shed. They don’t often have the tools, nor the knowledge to prepare the site themselves, and we often recommend that they use a professional to do the job. We also urge them to check their local regulations, such as zoning and setback requirements, which can easily complicate the site preparation process, especially if customers are unaware of them.

“The biggest challenge is the customer who underestimates the importance of a level and well-prepared site and either does it themselves without the proper tools and knowledge or hires someone (sometimes even a buddy or family member) who is also not professionally trained.  Those customers who cut corners on preparation often find problems later on, such as uneven settling. We try to prevent these issues from arising by providing the service through a reputable excavator whom we trust to do the job well for our customers.  We also offering a site prep instructional diagram to help the customer who feels confident in preparing their shed site themselves.”

Kontis added these tips:

“Education: It’s important to educate the customer early in the process with a detailed explanation of the importance of a properly prepared and level pad. Nobody wants to get a call from the customer who can’t open their doors because the shed has settled so badly.  

Transparency: We find it is important to be upfront about the timeline needed for site prep, including any potential delays due to inclement weather, etc. We explain that the shed construction timeline is separate from the site prep timeline, and they might not be completed at the same time. But of course, the pad will always be done before the shed gets scheduled for delivery.  

Local Regulations: We encourage all customers to check with their local municipality about a shed permit, as well as any HOA restrictions. They certainly don’t want to start a site prep or shed delivery in an area that would cause issues with the regulations.  

Support: Offer a list of reputable local excavators for a proper site preparation if the customer wants to shop around. Or, provide a quote for our in-house excavator to do the work, which we will warrant is done correctly.

By being proactive with information, we can minimize surprises for our customers and assure the longevity of their shed foundation.”

Foundation Options

There are a number of commonly used shed foundations, each with pros and cons. An important factor to consider is to ensure that the foundation type used doesn’t void the manufacturer’s warranty and that it meets local zoning and permit requirements. Regardless of foundation choice, the site should be properly prepped by removing tree roots, rocks, and vegetation, which can interfere with creating a flat, consistent, and solidly packed foundation. 

Gravel With a Pressure-Treated Wooden Frame 

Pros: Crushed stone, commonly referred to as “gravel,” is relatively inexpensive and simple to install, can be used to level out uneven ground, and provides good drainage.

Cons: Gravel may shift over time, which can reduce the stability and structural integrity of the shed. It may not be stable enough for heavier sheds, and the pressure-treated wood frame may eventually rot. The gravel is in direct contact with the shed, which limits air flow underneath, allowing shed base rot to occur faster, and creating easier access to rodents and other animals.

According to Site Prep (siteprep.com), a company specializing in preparing sites for shed installation, gravel pads are the best choice for most situations. The site says, “Crushed stone (or ‘gravel’) shed foundations are the best all-around shed foundation option. While various shed foundation types are available, crushed stone foundations provide the best combination of affordability, durability, and ease of construction. In fact, many shed manufacturers now recommend or require a crushed stone base for their buildings, with some shed companies even making their warranties contingent upon it.”

Site Prep also explains why the term “gravel” isn’t really accurate. “Gravel actually refers to round river stone, which is not suitable for a foundation. Our shed foundations are built with crushed stone. Crushed stone is ideal for a shed foundation because its uneven shape allows it to be tightly compacted into a firm base, while still allowing water to drain away from the shed.” The site recommends “3/4” clean stone,” which is what the company uses for all its shed foundations. 

Site Prep recommends that a crushed stone foundation be a foot larger than the shed all the way around it. “A gravel shed foundation should extend 12” past your shed in each direction. For example, a 10’x12’ shed would require a 12’x14’ gravel shed foundation. The situation is different for a concrete foundation, however. “If you’re going with a concrete pad and your shed doesn’t have a floor, the foundation should be the same dimensions as your shed.” 

While crushed stone is one of the most widely used and recommended options, others include the following:

Pavers

Pros: Pavers are relatively inexpensive and easy to place. They don’t require a treated wood frame to hold them in place, and they allow water drainage. 

Cons: They will shift over time, reducing shed stability and structural integrity. They’re in direct contact with the shed, which limits air flow underneath, allowing shed base rot to occur faster, and creates easier access to rodents and other animals.

Plastic Grid Base Filled with Gravel or Sand

Pros: Plastic grid bases are relatively inexpensive and easy to install. They allow good water drainage. 

Cons: Plastic grid bases are not well suited for heavy sheds and need careful installation to ensure they’re level and stable. In addition, they’re in direct contact with the shed, which limits air flow underneath, allowing shed base rot to occur faster, and creates easier access to rodents and other animals.

Concrete Blocks

Pros: Concrete blocks are affordable and keep the shed off the ground to allow airflow underneath, reducing access to animals and slowing rot. 

Cons: It can take some skill to install blocks square and level. Blocks can shift over time and reduce the shed’s structural stability, especially in areas with unstable soil or in colder climates susceptible to significant frost heave. They’re not well suited for large or heavy sheds, as their narrow footprint makes them susceptible to sinking into the ground. 

Pier and Beam 

Pros: A pier and beam foundation is cheaper and easier to install than a concrete slab, while still offering stability. It’s a good solution for installing sheds on a slope. It keeps the shed elevated, which allows air flow beneath to slow rot and helps keep pests from entering the shed. 

Cons: A pier and beam foundation will require a professional to install properly, so it will be a more expensive option. If the piers aren’t installed deep enough, they’ll be susceptible to frost heave. While a pier and beam foundation is sturdy, it can’t handle the weight capacity of a concrete slab. 

Concrete Slab

Pros: A concrete slab is very stable and can bear heavy weight, so it’s the best option for large, heavy sheds. In addition, the solid slab helps prevent pests from entering the shed.

Cons: A concrete slab will typically require a permit and is more expensive than other options. In warmer climates, floating concrete slabs, which are slabs without footers, may be permitted, but in colder climates, where frost heave occurs, building codes may require footers, which will increase the cost. While a concrete slab is more permanent, that also means more labor and expense to remove it if the owner wants to use that space for something else. 

Conclusion

Potential shed customers need to know best practices for site preparation and for foundation options for their unique needs. While crushed stone foundations are widely regarded as an affordable and durable option, other foundation choices, such as pavers, concrete blocks, pier and beam, and concrete slabs, may better suit specific circumstances. Assisting customers with this background information will help them get the most from their shed and create long-term satisfaction with their purchase. GSCB