How to Build Shed Foundation Piers the Right Way

Building a shed is exciting until you start thinking about the foundation. You want something solid that won’t shift, crack, or sink over time.

I’ve been there too, thinking if the ground will hold or if the frost will ruin all the work. That’s when I learned about shed foundation piers.

They give your shed real stability, even on sloped or soft ground. In this post, I’ll walk you through exactly how to build them, tools, materials, clear steps, and a few tips I wish I had known sooner.

If you’re looking for something strong, lasting, and manageable on your own, you’re in the right place. Let’s get it done right the first time.

Why Shed Fountain Piers are Worth It

Shed foundation piers are vertical concrete supports placed deep in the ground to hold up your shed.

They work by spreading the weight of the shed evenly and keeping it steady, even when the soil shifts during seasonal changes.

Unlike gravel pads or deck blocks that rest near the surface, piers are installed below the frost line to prevent movement caused by freezing and thawing.

This makes them a smart choice for cold climates. You’ll also want to consider piers if your yard isn’t level or if your shed will be used to store heavy equipment.

They’re strong, long-lasting, and reliable for building on uneven or soft ground. They also make it easier to build on slopes without needing to level the entire area first.

Tools and Materials Checklist

Here’s everything you’ll need to build shed foundation piers, from digging the holes to pouring and curing the concrete:

• Post hole digger or auger
• Level
• Tape measure
• String line and stakes
• Circular saw (if trimming forms)
• Wheelbarrow and mixing tools (if not using premixed bags)
• Concrete mix (fast-set or standard)
• Sonotube forms (12”–24” diameter)
• Gravel for base
• Rebar (optional but recommended)
• Post base anchors or brackets
• Marking paint or stakes
• Water (for mixing)

How to Build Shed Foundation Piers (Step-by-Step)

Follow these simple steps to install shed foundation piers correctly. Take your time with each stage to get a strong, level base.

Step 1: Plan and Prepare the Area

The project began by clearing and leveling a section at the back of the garden, creating a flat surface for the base.

Wooden stakes were placed to mark the corners of the 4×3-meter garden room. A string line was stretched between the stakes, and the 3-4-5 triangle method was used to ensure the corners were perfectly square. This setup helped guide the exact placement of the foundation piers.

Step 2: Dig and Compact the Holes

Twelve holes were dug across the marked area—four rows with four holes each. Each hole measured approximately 600mm in width and 500mm in depth.

After digging, the soil at the bottom of each hole was tamped down firmly. Compacting the base in this manner ensures that the concrete blocks won’t settle or shift later.

Step 3: Add Hardcore for Stability

Once the holes were ready, MOT Type 1 hardcore was added to each one. This crushed stone was poured in, then leveled and tamped down. The compacted hardcore layer helps with drainage and gives a solid base for the blocks to sit on.

Step 4: Lay and Level Concrete Blocks

The first concrete block was placed on top of the tamped hardcore. A long plank and a level were used to check that each block matched the height of the others.

Once adjusted, a layer of mortar was added under and between the blocks. A second block was stacked on top of each one, forming the final pier height across the whole base.

Step 5: Finish With Membrane and Limestone

After the piers were complete, a landscaping membrane was laid across the entire foundation area. Openings were cut for each concrete block.

Then a layer of clean limestone gravel was spread over the membrane. This final layer helps prevent weeds and keeps the area neat and stable, ready for the shed subfloor to be built.

Shed Foundation Piers vs Other Options

When deciding how to support your shed, it helps to compare pier foundations with other common base types, such as gravel pads or concrete slabs.

Pier Foundation

Piers are concrete supports placed deep into the ground, usually with cylindrical forms called sonotubes.

These piers are spaced in a grid pattern and extend below the frost line to prevent shifting in cold weather.

You pour concrete into each form and add metal brackets to hold the shed frame in place. This type of foundation keeps the shed off the ground, allowing air to circulate underneath.

Gravel Pad

A gravel pad is a layer of crushed stone built up to create a flat, level surface for your shed. To install one, you dig down a few inches, lay landscape fabric to block weeds, and fill the space with layers of compacted gravel.

The shed either sits directly on the gravel or rests on concrete blocks placed on top. This is the easiest and most budget-friendly foundation option.

It’s ideal for small to mid-size sheds on flat ground, providing good drainage that keeps moisture away from the floor.

Concrete Slab

A concrete slab is a flat, solid base poured directly onto the ground. It involves building a wooden frame, placing rebar or mesh for reinforcement, and pouring in wet concrete until it’s smooth and level.

This is the most substantial and permanent type of foundation. It can handle heavy equipment, significant structures, and long-term use.

Concrete slabs also resist pests and don’t shift easily. However, they’re the most expensive and most complex to build on your own.

Comparison Table: Pier vs Gravel vs Slab

Here’s a quick look at how shed foundation piers compare to gravel pads and concrete slabs in key areas:

Feature	Piers	Gravel Pad	Concrete Slab
Frost Resistant	Yes	No	Yes
DIY Friendly	Moderate	Easy	Hard
Cost	Medium	Low	High
Drainage	Good	Good	Poor
Best For	Cold/slope	Budget sheds	Heavy sheds

Common Mistakes to Avoid

These mistakes can weaken your foundation or lead to problems later. Catch them early to save time and avoid costly fixes.

• Not leveling piers with a string line or laser level
• Building the shed before fixing uneven pier heights
• Digging holes too shallow above the frost line
• Skipping gravel, which leads to poor drainage
• Using clay-heavy or wet soil for backfilling

Important Build Tips

Following these tips will help you build a pier foundation that stays solid and performs well over time.

• Always check your local frost line depth and dig below it
• Add 4–6 inches of gravel at the bottom of each hole
• Use rebar to strengthen piers, especially for large or heavy sheds
• Backfill with gravel or dry soil to prevent shifting or water buildup
• Double-check the pier height before the concrete sets to keep everything level

Conclusion

You’ve just learned how shed foundation piers can take the worry out of building a strong shed base.

From digging deep enough to curing the concrete right, every step matters, and now you know how to do it without second-guessing.

I’ve made a few of these mistakes in the past, and sharing this guide is my way of helping you avoid them.

The key is patience and precision. It really pays off when your shed stays solid through every season.

If you found this helpful, I’ve got more straightforward shed and backyard tips waiting for you.Don’t forget to check them out on the website and keep building with confidence.