11 Most Popular Shed Foundations (#3 is My Favorite)

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Ever opened the garage door and can’t find anything, or fit the car in? The yard is cluttered with kids’ bikes and the snow shovels greet visitors at the door in the summer? Where to put it all?

You need a shed! Everyone has a shed! They lean this way or that way, the door sticks, or the floor rots out. Some are wood, others plastic or steel, do-it-yourself or prebuilt. Where to start?

The best place to start is the foundation. A proper base will support the type of shed you build or buy. What kind of foundation do you need? What are their pros and cons of each? What’s on-grade or permanent? Do you need a Building Permit? What will it all cost?

This article about most popular shed foundations will help answer these questions. It’ll help you decide on the best foundation for your shed.

Does My Shed Need a Foundation?

Ever stood in your yard after it rains? Your feet get wet. The same thing happens to your shed. If it sits on the ground, it will get wet from the ground moisture. This will cause wood to rot and metal to rust. It will cause the contents of the shed to be damp.

Additionally, the ground isn’t flat. Uneven ground makes doors stick and affects the stability of your shed. A foundation lifts your shed off the ground. It provides a stable and level base so the doors open, and your shed lasts longer.

Contact Your Local Building Inspector

Before you begin any construction project, you should consult your local Building Inspector. If you don’t you could face fines and/or have to remove what you’ve built.

Some communities have restrictions on the size and style of outbuildings (sheds). The Inspector will know the limits and are often a fountain of information. They will inform you about any setbacks or easements to respect.

They should also be familiar with soil types in their local. If you need a Building Permit, they’ll let you know that too.

On-Grade vs Permanent Foundation

An On-Grade foundation is one that sits on the ground. It can be a skid, gravel, patio stone, block or post, or even plastic construction. In 20 years you could remove your shed.

Take the base out is as easy as putting it in, rake it over, plant grass seed, and it would disappear. A Permanent Foundation is just that, permanent.

It’s a concrete slab, excavated block or poured wall, or concrete pier. In 20 years it will still need a lot of work to remove. The pros and cons of each are below.

 

Popular Types of Foundations Used for Sheds

On-grade Foundations

#1 Concrete Pavers

Pavers for shed foundation

An easy foundation for the beginner and good for prebuilt or a home built sheds. A foundation of pavers sits on leveled exposed ground or a sand base. They provide a solid flat base upon which to build or set a shed and evenly support the floor.

The bigger the paver, the heavier it is, but the fewer you need. Pavers are great on flat ground for smaller sheds of wood, metal, or plastic construction with or without a floor. Using pavers places the entry close to, or on the ground so good for riding lawn mowers or quads.

Complexity: Easy
Once the ground is level, pavers are easy to lay. If placed on the sand there’s an extra step leveling before putting the pavers. Sand does make it easier to level the pavers too.

Construction Cost: $100.00-$200.00
The cost of pavers depends on their size, color and shape. Some large pavers are available with steel mesh inside them but are more expensive. I prefer 24”x24” or 24”x30” (heavier but cover more). Adding a sand layer increases the cost too.

Pro Tips:

  • Throughout the build, check your levels.
  • Use sand to make leveling easier.
  • Garden cloth under the pavers helps reduce weeds coming up in the cracks.
  • Don’t make it larger than the shed base as roof run-off can pool and seep into your shed.

Pros

  • Available in several colors, shapes and sizes
  • Quick and easy install
  • Continuous support of shed floor, or makes a good floor
  • Can secure shed/walls to pavers

Cons

  • Can settle into the soil over time
  • Pavers become uneven to each other
  • Can crack with heavy loads
  • Not suitable for large sheds
Lay Shed Foundation With Paving Slabs

 

#2 Solid Concrete Blocks

solid concrete blocks base

Image courtesy of finehomebuilding.com

A relatively easy foundation for the beginner and a good base for any sized shed. Good for prefab or home built sheds. Concrete blocks are square or rectangular in shape.

Only use solid-concrete blocks. They sit on the ground and need to be level, and level with each other. Shed dimensions and ground slope dictate how many blocks you need.

The sloped ground may need stacked blocks to form a tower level with other block towers. Support the corners and every 6’ to 8’ on the perimeter (closer if for heavy equipment) and the middle area. An 8’x12’ shed would use 6 blocks, more if you use towers for leveling.

Complexity: Relatively Easy
You are not leveling the ground, only the blocks. The difficult steps are leveling the blocks with each other and squaring the corners. The level of difficulty increases for sloped ground.

Construction Cost: $0.00 – $100.00
The cost of solid-concrete blocks depends on their size and shape. The number required will depend on the dimensions of the shed and the slope of the ground. How high off the ground you want the shed to be is also a factor.

Pro Tips:

  • Suitable for flat yard or slopes with a difference of 24” or less for the run of the shed
  • Always re-check your levels as you build. Great for use with any shed material
  • Use for sheds, cabins and cottages
  • Not ideal for heavy machinery due to structural weight bearing and possible vibration issues
  • The floor isn’t fully supported and vibrations can cause block towers to shift
Pros

  • Available in several shapes and sizes (12”x12”x4”, 4”x 8”x16”, 2”x8”x16”)
  • Quick and easy to install
  • Easy to stack and level
  • Good for small or large sheds

Cons

  • Can sink over time on the wet soil
  • The distance between blocks is not supported
  • Not suitable for slopes of greater than 24”
Build Shed Foundation with Concrete Blocks

 

#3 Deck Blocks

Deck block foundation

An excellent foundation for any size shed. It is also fairly easy for a novice DIYer. Good for prefab or home built sheds. Deck blocks are square based-pyramidal in shape.

They have channels in the top for wooden framing. They sit on the ground and need to be level, and level with each other. Shed dimensions determine the number of blocks you need.

Support each corner and every 6’ to 8’ on the perimeter (closer if for heavy equipment) and through the middle area. An 8’x12’ shed would use 6 deck blocks – 3 per long side. Good for flat lot, not slopes.

Great for use with any shed material. Use for sheds, cabins and cottages. Places the shed closer to the ground; so easy access for lawn mowers or quads.

Not ideal for heavy machinery due to structural weight bearing as the floor isn’t fully supported.

Complexity: Relatively Easy
You are not leveling the ground, only the deck blocks. The difficult steps are leveling the deck blocks to each other and squaring the corners.

Construction Cost: $0.00 – $100.00
Deck blocks and patio stones are similar in price. The number required is less though and depends on the dimensions of the shed.

Pro Tip: Remember to check your levels as you build.
Pros

  • Quick and easy to install
  • Easy to leveled
  • Good for small or large sheds

Cons

  • Can sink over time
  • The distance between blocks is not supported
  • Not good for sloped surface
Build Shed Base with Deck Blocks

 

#4 Gravel Pad and Timber Frame

gravel pad and timber frame foundation

Image courtesy of Classic Buildings

A relatively easy foundation for any size shed and great for ready-made or home built sheds. The size makes this more difficult for the novice DIYer.

The gravel pad and timber frame foundation is good for the flat ground. Use pit-run or 1”-crusher run gravel. It has smaller particles in it and packs into a more stable base.

Compact the gravel using a gas powered compactor; working to keep the gravel level. The pad is on the ground and should be 2’ wider and longer than your shed.

Remove the sod and/or cover it with garden cloth, then spread out and tamp down the gravel. It should be 4”-6” thick and level. Shed dimensions dictate how large an area you need.

Place pressure treated 4”x4” (or 4”x6”, 6”x6”) timbers on the gravel in the same dimensions as the shed.

Use a half-lap joint where the timbers meet. Square the corners and level the lumber with each other. Drill the joints and hammer a length of rebar through into the ground.

Complexity: Relatively Easy
Level the ground or mask slight imperfections under the level gravel layer. Leveling the 4”x4’s to each other and squaring the corners are the difficult steps for this foundation.

Construction Cost: $200.00 – $400.00
The cost of gravel fluctuates with location. Rolls of garden cloth often go on sale. The amount of gravel and the number of 4”x4”s depends on the dimensions of the shed.

Pro Tips:

  • A 6” gravel thickness is better than 4”
  • The gravel has to be level
  • If you need to add a second layer of pressure treated lumber use galvanized spikes to join them to the layer below
  • Recommend pre-drilling so it’s easier to nail
Pros

  • Quick and easy to install
  • Easy to leveled
  • Shed is on or close to land level
  • Use with sheds with or without a floor
  • Good for smaller or large sheds

Cons

  • Can sink over time on the wet soil
  • Higher risk of ground contact and rot
  • May need a drainage ditch
  • May need a retaining wall to hold gravel in place
  • Not suitable for sloped yard
Build Gravel Pad for Your Shed

 

#5 Skid Foundations

shed skid base

Image courtesy of Shed to House

A skid foundation is a quick and easy way to support a shed and easy for even the beginner to build. We’re not talking commercial delivery skids. It comprises of 2 or more pressure treated 4”x4”s, 6”x6”s, 8”x8”s or even logs laid parallel to support the length of the building.

The shed sits on and is evenly supported by, the skids. The skids, also called runners, usually sit directly on the ground. This means you want relatively flat terrain.

Historically, the skids meant the shed could be skidded to another location. It is a good idea to dig a trench where the skids will lay, then tamp in gravel ensuring the surface is level and drained.

This will help protect the wood and make leveling easier. The trench should be wider and longer than your skid. I helped move a 10’x30’ cabin built 90+ years ago on log skids. We used ropes and a half to truck; the 100 yard move was easier than expected.

Complexity: Easy
Level the ground or mask slight imperfections under the level gravel layer. The difficult steps are leveling the skids themselves and to each other.

Construction Cost: $0.00 – $100.00
The amount of gravel (if used), plus the dimension and number of skids (determined by the shed size), affect the cost.

Pro Tips:

  • A 6” gravel thickness in the trench is better than 4”
  • The gravel has to be level
  • The bigger the shed, the bigger the skid dimension should be
  • You can use 2”x6” or 2”x8”s nailed together and sitting on the edge
Pros

  • Quick and easy to install
  • Easy to leveled
  • Shed is movable
  • Shed is on or close to land surface
  • Good for smaller or large sheds

Cons

  • Can sink over time on the wet soil
  • Higher risk of ground contact and rot
  • Not suitable for sloped lot
Build Shed Base and Floor on Skids

 

#6 Plastic Foundations (or Plastic Garden Shed Base Grid)

Plastic Foundation

HAWKLOK Plastic Shed Base Kit

A newer type of foundation made from recycled material. It’s easy for the beginner to put together and good for prebuilt or a home built sheds.

It sits directly on the ground, so the flat ground is best. It is similar to concrete paver construction, but much lighter. The ground preparation is easy, ensure it is firm, flat, and fill in any depressions and remove high spots.

Plastic Garden Shed BaseOnce the ground is level, roll out the garden cloth. Place the interlocking grid blocks, connect together, and level. The blocks can even be cut to size with a hand saw.

Once the base is level, fill the open grid with pea gravel. The base should be the same dimensions as your shed, but can be wider.

The grid holds the pea gravel in place and allows moisture to percolate through. The grid also helps keep the base of the shed drier than concrete pavers.

The plastic grid can be used for sheds with or without floors and provides even support for floors.
Ideal for use with riding lawn mowers or other wheeled equipment as it sits on or close to ground level. Available here.

Complexity: Easy
Level the ground or mask slight imperfections a sand layer. The difficult steps are leveling the grids themselves and to each other.

Construction Cost: $150.00 – $300.00
The amount of pea gravel, garden cloth, and number of grids affect the cost of construction.

Pro Tip: Use sand level the ground. Remember to recheck for level as you work.
Pros

  • Quick and easy to install
  • Easy leveled
  • Shed is on or close to the land level
  • Good for smaller or large sheds

Cons

  • May sink over time
  • Not widely available
  • Not good for sloped ground

 

#7 Kit from Manufacturer

Kit from Manufacturer Arrow FDN1014 Storage Shed Base Kit

Some small shed manufacturers offer foundation kits for their sheds. Foundation kits are available in various styles.

They can be used for the manufactured shed, or to support other small sheds of the same size. It’s easy for the beginner to put together.

It sits on the ground which means you need a flat area. The foundation pieces may also be lighter weight for moving around.

The ground preparation is easy too. Ensure it is firm, flat, and fill in any depressions and remove high spots.

Prepare the ground. Place the foundation pieces (following the Manufacturer’s instructions), connect together, and level. The base should be the same dimensions as your shed.

You may have to purchase other required materials to complete some manufactured foundations.

Complexity: Easy
Leveling the ground and manufactured foundation are the difficult steps for this foundation. Reading and interpreting the instructions can be difficult too.

Construction Cost: $50.00 – $100.00
The cost of the kit, garden cloth, plus any required materials, set the cost (see today's price here).

Pro Tips:

  • Use sand to level the ground and place garden cloth down before putting the foundation down
  • Remember to recheck for level as you work
  • Tighten all bolts/screws before they disappear under other structural materials.
Pros

  • Quick and easy to install
  • Easy to level
  • Shed is on or close to ground level for easy access
  • Good for smaller sheds

Cons

  • May sink over time
  • Higher risk of ground contact and rot/rusting
  • Not good for sloped ground
  • Often requires other materials be purchased

 

Permanent Foundations

Always check with the Building Inspector before beginning any permanent foundation.

#8 Concrete Piers and Beams

Concrete Piers foundation

Image courtesy of Green Button Homes, LLC

An excellent foundation for any shed size, but more difficult to build. Good for home built sheds and some prefab.

The piers are concrete poured into holes dug or drilled into the ground to the frost line (or bedrock).

The holes should have 6”s of gravel in the bottom for drainage. There are plastic pier forms which can be set into an excavation dug to the frost line. They are then buried and filled with concrete (after being plumbed and leveled).

The most common though are cardboard tubes. They are placed into the holes, plumbed level and secured in place. Backfill the space around the tube, then fill with concrete.

All the tubes/forms need to be in aligned in their exact location on the string line. The piers need to line up with the framing they will attach to and support.

Each pier should extend at least 6” above ground level, but can extend higher if desired. The top of the piers should be level with each other.

Pressure treated 4”x4” (6”x6”, 8”x8”) posts can sit on top of the piers to provide a level surface for the pressure treated beams.

Before the concrete hardens in the piers, set pier or post ties and align in place. Shed dimensions determine the number of piers you need. An 8’x12’ shed would use 6 piers – 3 per long side.

Once the piers have cured, beams can be set in place on the piers (or pier and post) and leveled with shims.

Suitable for flat ground or slopes.
Great for use with any shed material.
Use for sheds, cabins and cottages.

Complexity: Difficult
You are not leveling the ground, only how far the piers extend above the ground. Making the piers level vertically and horizontally increases the level of difficulty.

Construction Cost: $200.00 – $800.00
The concrete, number of tubes/forms, pier or post ties, plus dimension lumber for beams all affect the cost. The number piers required will depend on the dimensions of the shed. The distance to the frost line and the slope of the ground are also factors that affect the cost.

Pro Tips::

  • Re-check your horizontal and vertical levels
  • Triple check that the 4 corner posts remain square
  • Set the 4 corners first, it makes it easier to square and level the other piers
  • Good helpers are an asset.
Pros

  • Great for most soil conditions
  • Exceptional for areas that experience frost
  • Provide a permanent level base
  • Good for small or large sheds

Cons

  • Little forgiveness for errors.
  • The distance between piers is not directly supported
  • Difficult for the beginner
Build Pier Shed Foundation

 

#9 Concrete Slab – Best Shed Foundation

building concrete slab shed foundation

A great foundation for any size shed: ready-made or home-built, a garage, or even a 2 story house. The different steps are what make this more difficult for the novice DIYer, and it’s a more difficult foundation to build.

Shed dimensions dictate how large an area you need. The finished slab is strong enough to support vehicles and sits on the ground so it’s easy to drive in to. Ensure you have access to the concrete truck, or you may need a pumper truck or crane at added expense.

This is NOT a step-by-step for making a concrete slab. It identifies many of the steps you need to become knowledgeable about.

Set the 4 corner stakes, ensuring the corners are square. Use a string line and level to determine ground slopes. The more slope, the more material to move. If built on solid, well-drained soil your slab will last longer.

Remove the sod and top 4” – 6” of soil creating a level base. Using 2”x12”s to form the perimeter; stake the corners and adjust so they are square and level. The thickness of concrete and gravel determines how high the forms need to be.

4”-6” of concrete on 6”-8”s gravel places your forms several inches off the ground. If placing rigid foam under the concrete pad you’ll need to raise the forms higher. If you want a 4” or 6” thick concrete pad, then the tamped gravel needs to level out 4” or 6”s below the top of the forms.

Once the forms are in place, they should be vertically braced and the top diagonally braced every 2 feet. Spread the 6” – 8” of gravel to fill the pad (You may need engineered gravel). Compact the gravel using a gas powered compactor; working to keep the gravel level.

The perimeter of your gravel pad should slope downward to 2”s thick of gravel for the outside 12”s of the perimeter. This makes a footing which helps support the walls of your building.

Cover the pad with 6 mil plastic (poly) sheet to help keep moisture out of your concrete pad once it sets. Use ½” rebar in the perimeter and lay a 4’ grid of rebar on the gravel pad. Bend it at the perimeter to connect with the perimeter rebar.

You can use 6”x6” steel mesh instead of the rebar grid. Use blocks or rebar rests to lift the rebar off the poly. You’re now ready to pour, screed, vibrate the perimeter, and finish the pad surface as desired – smooth, glossy, or brushed.

If attaching a sill plate, place anchor bolts every 4 feet around the perimeter before the concrete hardens (not in doorways). You may need expansion grooves cut in too depending on the size of the concrete pad.

If it looks like rain, cover with plastic to protect the surface. Once the concrete is cured (24 hours), remove the forms. Before you backfill you may want to address any drainage issues.

Complexity: Difficult
There are many steps to this type of foundation. It is a permanent foundation, so mistakes are permanent.

Construction Cost: $2500.00 – $4000.00 (for a 300sqft pad)
The cost of materials will vary with location. Equipment rentals/hires and Building Code requirements also add to the cost.

Pro Tips::

  • Hire an excavator to remove the soil and level the site
  • Use a laser level to set the levels
  • Use deck screws instead of nails to hold the forms; easier to make adjustments and to dismantle at the end of the project
  • The forms can be used in the construction of your building, reducing cost and waste
Pros

  • A permanent foundation
  • Will support heavy loads
  • Shed is on or close to the surface of the land for easy access
  • Use for sheds with or without a floor
  • Great for smaller or large sheds

Cons

  • Needs to be above freezing for pouring
  • Can crack over time if ground slumps or shifts
  • Risk of ground contact and rot if the ground slope is wrong
  • May need a drainage ditch
  • May require a retaining wall to hold slopes in place
  • Not suitable for sloped site
Build Concrete Slab Shed Base

 

#10 Post and Beams

Post and Beams Foundation

Image courtesy of StorageBuildingsUnlimited

This is a good foundation for any size shed; home built or prefab. It is similar to the concrete pier construction but more forgiving.

It uses 6”x6” or 8”x8” pressure treated posts placed in holes dug or drilled into the ground to the frost line (or bedrock). Only dig down as far as you need, the posts should sit on undisturbed soil. The holes should have gravel in the bottom for drainage.

You can mix and pour a bag of concrete into each hole too. The posts are placed into the holes, plumbed level and secured in place, then backfilled and tamped. Leave the packed soil mounded around the post.

All the posts need to be in the exact location to line up with the framing they will attach to and support. Each post can extend several feet above ground level. The top of the posts can be leveled with each other after they are all set. They provide a level surface for the pressure treated beams to sit on.

Cut the posts level with each other, then notch for the beams (make sure to notch the correct side of each post).

Shed dimensions determine the number of posts you need. An 8’x12’ shed would use 6 posts – 3 per long side. Once the posts are notched, place the beam in place, drill holes for carriage bolts, and bolt into place.

Diagonal braces should be attached between the posts to beam for lateral support. Good for flat ground or slopes. Great for use with any shed material. Use for sheds, cabins and cottages.

Complexity: Slightly Difficult
You are not leveling the ground, only how far the posts extend above the ground. Making the posts level vertically and horizontally increases the level of difficulty.

Construction Cost: $200.00 – $800.00
Gravel, concrete, number and dimensions of posts, and beams all affect the cost. The number posts required will depend on the dimensions of the shed. The distance to the frost line and the slope of the ground are also factors that affect the cost. How high off the ground you want the shed to be must also be considered.

Pro Tips::

  • Re-check your horizontal and vertical levels
  • Triple check that the 4 corner posts remain square
  • Set the 4 corners first, it makes it easier to square and level the other posts
  • Good helpers are an asset

Pros

  • Suitable for most soil conditions
  • Excellent for areas that experience frost
  • Provide a permanent level base
  • Good for small or large sheds

Cons

  • A lot of planning for placement and leveling involved.
  • The distance between posts is not directly supported
  • Can be difficult for the beginner

 

#11 Screw Piles

screw piles shed foundation

Image courtesy technometalpost.com

This is a good foundation for any size shed or house; home built or prefab. Great for any soil type too.

It is similar to concrete pier and post and beam construction. The screw piles are galvanized steel posts with a screw end. They come in a choice of lengths and diameters. Some need a small excavator with a special attachment to screw them into the ground to the frost line.

Other types use a special handheld powered screwdriver – hope you have strong wrists. The screw helps to prevent vertical frost lift. There is also minimal settling since the soil is undisturbed by digging.

Once in place, attach the beams and joists and build on. Suitable for flat ground or slopes. Great for use with any type material.

Complexity: Slightly Difficult
You are not leveling the ground, only how far the posts extend above the ground. Making the piles level vertically and horizontally increases the level of difficulty. This becomes Easy if you hire a certified installer and get a guarantee.

Construction Cost: $500.00 – $1000.00
The screw piles, a method of installation, and the lumber for the beams affect the cost. The number piles required will depend on the dimensions of the building. The distance to the frost line and the slope of the ground are also factors that affect the cost.

Pro Tip: Hire an experienced certified installer with a guarantee.
Pros

  • Suitable for any soil conditions
  • Excellent for areas that experience frost
  • Provide a permanent level base
  • Good for small or large sheds
  • A quick installation

Cons

  • requires specialized equipment or hired specialists.
  • The distance between piles is not directly supported

 

How to Choose the Right Foundation for My Shed?

Your choice of foundation is an important decision. It helps keep your shed level and dry, and provides a stable base for it. All extend the life of your shed.

Most on-grade foundations are easier to build and don’t need a lot of special tools or expertise. Select the one that fits the type of shed you want it to support, and the location you want it to in. Your Building Inspector can answer many of your questions too.

Permanent foundations tend to be more complicated and may need more ability. This doesn’t mean you can’t do it; it means you need to become more knowledgeable about your choice of foundation. Always involve the Building Inspector with all permanent foundations.

Base your choice on the size and type of shed you want to build. What you’re going to store in it, what the location requires, and your budget also affects your decision. A small shed has different requirements than a large one. The open bottom or built-in floor, sloped or flat ground, all affect your choice.

Hopefully, this article has provided you with information to make your decision easier.

Your comments are appreciated. If you know someone who is thinking about building a shed, share with them if you liked it.

3 thoughts on “11 Most Popular Shed Foundations (#3 is My Favorite)

  1. What would you recommend that’s next to a new house? I’m expecting that there will be some settling and I have to make sure there is good drainage so the water of the shed and house doesn’t push the water next to my house foundation. Shed is 8’x10′ and the created a pad @ 2% away from the house.

    • How close you want to build your shed to the house?
      I would suggest to build a foundation with deck blocks and make shed freestanding (not attached to the house)
      Currently, I’m working on a post about how to build Lean To shed. Please come back in a couple of weeks and check it out. It will include a lot of details on how to build this type of sheds.

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