Building a Shed Foundation (2024)

By Amanda Lutz Updated May 13, 2024

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Adding a storage shed to your property or performing a backyard shed renovation can add value to your home and increase storage space. Our guide will help you decide the best shed foundation type for you, how to build a shed, and when to hire a professional.


Preparing for the Project

Building a shed foundation requires intensive planning, especially for larger sheds. Most local municipalities require that homeowners file for a building permit before they begin this home improvement project.

Once you secure a permit, determine where you want to put your shed and what size of shed you can fit in the space available. Consult building codes and any homeowner associations for guidelines, and get in touch with your local utility company by calling 811. The utility company will help you identify underground utilities so you don’t damage them during construction.


Shed Foundation Types and How to Choose

Shed foundation options include on-grade and frost-proof types. You can construct an on-grade foundation more quickly, cheaply, and easily, but if you’re looking for a larger or more permanent shed, you may want to consider a frost-proof foundation. Frost-proof foundations support more weight because their footings are below the frost line, preventing shifting during temperature fluctuations and the onset of frost heaves.

Before building a frost-proof foundation, determine where your property falls on a frost-line penetration map. You must place foundation footings below the frost line during installation. The further north you live and the colder the climate, the deeper you’ll need to dig foundation footings.

We’ve listed 12 types of shed foundation types, their benefits and drawbacks, and their frost-proof ratings below. Note that you’ll only be able to construct certain types of sheds on inclines or slopes.

TypeCostSloped SitesFrost-ProofBenefitsDrawbacks

Concrete blocks

$50–$100

Small only

No

Easy to install; inexpensive

Can’t anchor shed properly; doesn’t support structure evenly; may void shed warranties

Deck blocks

$50–$200

Small only

No

Easy to install; inexpensive; more supportive than concrete blocks

Can’t anchor shed properly; can’t use with pre-built sheds; doesn’t support structure evenly

Skid

$50–$200

No

No

Easy to install; inexpensive

Can sink or rot; requires extra materials

Gravel pad

$100–$400

Yes

Yes

Costs less than concrete; good drainage; supports structure evenly

May require extra footers to make frost-proof in some regions; more expensive than pavers

Metal jacks

$100–$400

Yes

No

Easy to install; good for small spaces

Can’t use for spaces six inches off level; won’t fit large sheds

Plastic grid

$100–$400

No

No

Easy to install; good drainage; supports entire structure

Made from plastic; gravel must be purchased separately

Metal foundation kit

$100–$800

No

No

Inexpensive

Can sink; not durable; only compatible with certain sheds

Pavers

$200–$1,000

No

No

Easy to install; inexpensive; supports entire structure

Can sink into ground over time; not as durable as other options

Concrete slab (floating)

$250–$3,000

Yes

Yes

Durable; simplifies shed anchoring; supports entire structure evenly

Expensive; more labor-intensive installation process

Pier and beam

$350–$2,000

Yes

Yes

Not as expensive as full concrete; can anchor easily to foundation

Beams may deteriorate over time; may raise structure to an awkward height; may void shed warranties

Concrete slab foundation

$800–$5,000

Yes

Yes

More durable; supports large structures

Expensive

Screw piles

$1,000–$4,000

Yes

Yes

Easy to install; can anchor easily to piles

Doesn’t support structures evenly; may raise structure to an awkward height; may void shed warranties; need power equipment to install

*Cost data in this article was sourced from Angi and HomeAdvisor.


How to Build a Shed Foundation

A post-and-beam foundation is a popular choice among the DIY crowd, no matter the shed size. Below is a step-by-step guide for how to build one.

Step 1: Lay Out the Area

You don’t want to build a shed on uneven ground. Find a location that’s close to level and doesn’t collect water. Mark the dimensions for your shed base with mason string and batter boards, which are temporary frames that contractors use to map excavation sites.

Step 2: Square

Square the area to ensure the foundation corners are at right angles. When you square your structure’s foundation, its floor joists and beams will fit together properly to ensure the building is structurally sound.

Square the corner by measuring three feet on one side and four feet on the adjacent side. Measure the distance between the two points. The distance will be five feet if squared correctly. Adjust the strings as necessary and repeat the process on all corners.

Step 3: Install Posts

Posts should be four feet apart. Measure for each post and mark them with more mason string and batter boards. Square the corner where you plan to plant the post using the same method listed in Step 2. Dig holes 12 inches round in diameter and 12 inches below your frost line with a post hole digger.

Pour approximately six inches of gravel into the hole, and compact it using a tamper. Once you’ve mixed the concrete according to the package’s instructions, pour it into the hole. Set the post into the hole, and make sure it’s level. Hold it straight as you pour concrete around the post’s sides, and top the concrete with soil.

Step 4: Cut the Posts

Once you’ve installed the posts around your foundation’s perimeter, determine how high you want to construct your shed floor and mark it on the post. Measure and cut posts with a saw until they’re all at the same height. Attach brackets and the beams you’ve chosen as your runners. Then you can begin building your shed’s floor frame.


Hiring a Professional

Labor costs for professional installation of your shed foundation fall between 40% and 60% of the total cost of the project. Taking the DIY approach to building a shed foundation may be more cost-efficient, but it requires some carpentry skills. We recommend hiring a professional if you don’t have home improvement experience, especially if you’re building a frost-proof foundation. Foundation repair is pricey—building a shed foundation yourself may lead to errors and damage down the line, even if you’re only constructing a small shed.


Our Recommendation

We recommend hiring a contractor to construct your shed foundation if you want a frost-proof foundation and don’t have any home improvement DIY experience. It’s more expensive to hire a professional up-front, but you’ll ensure the job is done properly and save on repair costs down the line.

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Shed Foundation FAQ

What is the best foundation for a shed?

The best foundation for a shed depends on your property and needs. A gravel pad foundation made with crushed stone is an excellent overall choice because it is inexpensive, stable, and easy to build.

Does a 10×12-foot shed need a foundation?

Yes, a 10×12-foot shed needs a foundation. Smaller sheds may not require a foundation, but a 10×12 shed requires a foundation to stabilize your structure.

What is the difference between a shed and a garage?

The difference between a shed and a garage centers on differences in size. If your structure can fit at least one vehicle, it’s a garage. A shed can have many different foundation types, while a u003ca href=u0022https://www.architecturaldigest.com/story/garage-renovation-ideas-that-boost-the-value-of-your-homeu0022 target=u0022_blanku0022 rel=u0022noreferrer noopeneru0022u003egarageu003c/au003e has concrete footings.

What tools are needed to build a shed foundation?

The tools you need to build a shed foundation include a tape measure, mason string, batter boards, a post hole digger, levels, and a saw, which you can pick up at hardware stores such as Lowe’s or The Home Depot. You’ll need protective gear and foundation materials, such as lumber and concrete. Building a shed foundation doesn’t typically require heavy equipment.

Do you need to pour concrete for a shed foundation?

You need to pour concrete for a shed foundation if your shed is 10×12 feet or larger. Shed installers recommend concrete foundations if the homeowner plans to store vehicles, heavy tools, or machinery.