October 1, 2024 Sebastian Lesec

How to Lay a Foundation for a Shed

When building a shed, the most critical first step is knowing how to lay a foundation for a shed that will last. A solid foundation ensures your shed remains stable, level, and protected from moisture and ground movement.

In this guide, we'll cover the different types of shed foundations, from easy on-grade options like skid, timber frame, and concrete blocks, to more permanent solutions such as concrete slabs, piers, and pole-barn foundations.

What this article covers:

How to Lay an On-Grade Shed Foundation
How to Lay v Permanent Shed Foundation
On-Grade vs. Permanent Foundations: What's the Difference?
How to Choose a Shed Foundation
How to Lay a Foundation for a Shed (FAQs)

How to Lay an On-Grade Shed Foundation

An on-grade foundation is perfect for smaller sheds or if you're planning to move your shed in the future. If you're tempted to put your small shed on grass, then we recommend going for one of these foundations instead.

According to our research, these foundations are also easier to install, making them ideal for beginners. Let's take a look at the different types of on-grade foundations you can build.

Skid Foundation

A skid foundation is one of the easiest to build, and after putting it to the test, we found it's also one of the quickest. If you're looking for how to make a shed base without concrete, then skids are one of the best ways to go. Steps for laying a skid foundation:

Prepare the ground: Remove grass and debris from the site.
Place the skids: Lay two or more long, pressure-treated timbers (usually 4x6 or 6x6) parallel on the ground.
Level the skids: Use a level to ensure the skids are even. Adjust by adding or removing soil underneath.
Build the floor frame: Construct the shed's floor frame on top of the skids and fasten it securely.

Tip: Skid foundations work best on flat terrain.

Timber Frame Foundation

A timber frame foundation offers flexibility for different flooring materials, and from our experience, it's a favorite for DIYers who want versatility. Steps for laying a timber frame foundation:

Create a gravel bed: Excavate the area and lay down 2-3 inches of compacted gravel.
Build the frame: Construct a rectangular frame using pressure-treated 4x4s or 6x6s.
Level the frame: Ensure the frame sits evenly on the gravel using a level.
Secure the frame: Fasten the corners with screws or spikes.
Optional floor material: Fill the frame with gravel, concrete, or decking boards.

Tip: Make sure the lumber is rated for ground contact to prevent rot.

Concrete Block Foundation

Concrete blocks are inexpensive and easy to source. According to our research, using concrete blocks for shed foundation provides a solid base without the hassle of digging or pouring concrete. Steps for laying a concrete block foundation:

Clear the site: Remove vegetation and create a level surface.
Lay the blocks: Place concrete blocks in a grid, spaced according to the size of your shed and floor joists.
Ensure level: Use a level to check that all blocks are even.
Place the floor frame: Build your shed's floor frame on top of the blocks.

Tip: Use solid concrete blocks rather than hollow ones, which can crack under heavy loads.

How to Lay a Permanent Shed Foundation

For larger sheds or those in areas prone to frost heave, a permanent foundation is the way to go. After putting these foundations to the test, we've found they provide long-lasting stability.

Concrete Slab

A concrete slab foundation is durable and ideal for heavy-duty sheds. Steps for laying a concrete slab foundation:

Mark the area: Outline the size of your slab.
Excavate: Dig to a depth of about 6 inches for the slab and deeper for the footings.
Create a gravel base: Lay 3-4 inches of gravel and compact it.
Build the form: Construct a wooden frame to hold the concrete.
Pour the concrete: Pour and level the concrete, reinforcing it with wire mesh or rebar.

Tip: A monolithic slab is the preferred option when erecting a shed base for frost-prone areas.

Concrete Piers

Concrete piers provide excellent support, especially for uneven ground. Steps for laying a concrete pier foundation:

Dig the holes: Space the holes in rows and ensure they extend below the frost line.
Place sonotubes: Insert fiber-form tubes into the holes.
Pour concrete: Fill the tubes with concrete and set post anchors before the concrete hardens.
Build the frame: Attach the shed's floor frame to the piers.

Pole-Barn Foundation

Pole-barn foundations are versatile and require less concrete. Steps for laying a pole-barn foundation:

Dig post holes: Space posts around the perimeter and ensure holes extend below the frost line.
Insert posts: Set treated poles in the holes.
Pour concrete footings: Pour concrete into the holes to anchor the posts.
Build the shed: Attach beams and build the walls directly on the posts.

On-Grade vs. Permanent Foundations: What's the Difference?

When it comes to shed foundations, choosing between on-grade and permanent options depends on your shed's size, location, and long-term needs. Let's break down the key differences between the two:

On-Grade Foundations

On-grade foundations rest directly on the ground, making them easy to install and ideal for smaller sheds under 200 square feet.

They're quick to set up and don't require deep digging or concrete pouring, making them great for sheds that might need to be moved later. These types of foundations are perfect for our 8x10 sheds or our 10x10 sheds.

However, they lack the long-term stability of permanent foundations and may shift over time, especially in regions with frost or heavy rainfall.

Permanent Foundations

Permanent foundations involve digging below the frost line and using concrete for added stability, making them better suited for larger sheds and areas with harsh weather.

Though they take more time and effort to install, they provide a sturdy, long-lasting base that resists shifting. This type of foundation is ideal for sheds over 200 square feet or those that store heavy equipment and are built to last in one spot.

Key Differences

Ease Of Installation: On-grade foundations are simpler and quicker to set up. Permanent foundations require more work but offer greater long-term stability.
Cost: On-grade foundations are typically more affordable since they don't involve digging or pouring concrete. Permanent foundations, on the other hand, are more expensive due to the materials and labor involved.
Durability: On-grade foundations may shift over time, especially in harsh weather conditions. Permanent foundations are much sturdier and can withstand extreme temperatures and ground movement.
Portability: On-grade foundations allow flexibility if you ever want to move your shed. Permanent foundations are fixed and not designed to be relocated.

How to Choose a Shed Foundation

Choosing the right foundation for your shed depends on a few key factors. From the size of your shed to the specific conditions of your property, making the right choice will ensure your shed remains stable for years to come.

Let's break down the main considerations you should keep in mind when selecting a shed foundation:

Shed Size

The size of your shed plays a major role in selecting the right foundation. Smaller sheds (under 200 square feet) can usually be supported by an on-grade foundation, such as a skid or concrete block, which is easier and faster to install.

Larger sheds, especially those storing heavy equipment or used as workshops, need a more durable solution like a concrete slab or pier foundation to handle the additional weight and provide long-term stability.

Ground Conditions

Ground conditions, including the slope and type of soil, are critical when choosing a foundation. On-grade foundations work well on flat, stable ground with good drainage.

However, if your land is uneven or prone to moisture retention, a permanent foundation, such as concrete piers, is better suited to provide long-term stability and prevent shifting or sinking over time.

Climate

Your local climate directly impacts your foundation choice. In areas with mild weather, on-grade foundations may suffice. However, if you live in a region with cold winters and frost heave, a permanent foundation like a concrete slab or piers is necessary.

These foundations extend below the frost line, ensuring the shed remains level and protected from ground movement caused by freezing temperatures.

Intended Use Of The Shed

What you plan to store or do in your shed matters. For lighter use, such as garden tool storage, an on-grade foundation can work well.

If your shed will house heavy machinery, vehicles, or be used for significant tasks, a permanent foundation offers the strength and support needed to handle heavier loads without cracking or shifting.

Permanence Of The Shed

If you think you may move the shed in the future, an on-grade foundation is more practical, as it's easier to disassemble and relocate.

However, if the shed is intended to stay in one place permanently, a concrete slab or pier foundation provides a stable, long-lasting base that will ensure the shed's longevity for decades.

Drainage

Proper drainage is essential to prevent water from pooling around or under your shed, which can cause structural damage over time. On-grade foundations like concrete blocks or skids are elevated slightly off the ground, allowing water to flow underneath.

This can be sufficient for areas with good drainage. However, if your site is prone to water retention, a permanent foundation, such as a concrete slab with proper slope and drainage channels, ensures water is diverted away from your shed, protecting it from rot and foundation shifting.

Local Building Codes

Before starting any foundation work, check your local building codes. Some areas have regulations regarding the type of foundation you can use based on the size of your shed or the climate.

For larger sheds or those in frost-prone regions, codes may require a permanent foundation like a concrete slab or piers.

On-grade foundations may not meet code requirements in some areas, so it's important to research your local laws and get all the necessary permits to avoid fines or future issues when selling your property.

Budget

Your budget is a key factor when selecting a shed foundation. On-grade foundations are generally more affordable since they require fewer materials and less labor. Foundations like skids or concrete blocks are cost-effective and can be installed quickly.

However, if you have a larger budget and want a more permanent, durable solution, investing in a concrete slab or pier foundation is worth it.

Although permanent foundations have higher upfront costs, they provide better long-term stability, which can save you money on repairs down the line.

Conclusion

Laying a proper foundation is the most important step in ensuring your shed is stable, durable, and long-lasting.

Whether you opt for an on-grade foundation for smaller sheds or a permanent solution for larger structures, choosing the right foundation based on factors like shed size, ground conditions, climate, and intended use is crucial.

By considering your budget, local building codes, and your skill level, you can confidently build a shed that meets your needs.

Ready to get started? Explore our wide range of high-quality shed kits and materials at Homestead Supplier to turn your shed project into a reality today!

How to Lay a Foundation for a Shed (FAQs)

What is the recommended shed foundation size?

Should a shed base be bigger than shed? Yes, the foundation should extend slightly beyond the shed's footprint by about 6 inches on all sides. According to our research, this provides proper support and protects the shed from water damage.

When should I hire a professional?

If your shed is over 200 square feet or the ground is uneven, hiring a professional might save you from costly mistakes. Also, if you're dealing with frost-proof foundations, it's best to get an expert involved.

Are there any other shed foundation types I should consider?

Yes! You can also consider alternative options like adjustable plastic or metal bases, which are quick to install, or even plastic grid systems for lighter-duty sheds.

If you want to learn more, why not check out these articles below:

Previous article Is a Shed a Permanent Structure?

Next article How to Make a Shed Base Without Concrete

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