If you’re looking to build a storage shed on your property, the type of foundation you choose is essential. The shed foundation will determine how solid and sound your shed floor is and whether or not the shed is portable. In other words, a solid foundation is vital to the integrity and quality of the shed.
There are quite a few different foundation options for your storage shed. You can opt for anything from concrete blocks to concrete piers to skids or even a solid concrete pad. While a concrete pad is a permanent foundation, it’s also the strongest and most sound. However, many people opt for a skid foundation or concrete blocks for versatility and portability.
It’s primarily up to you which foundation you choose for your shed. However, the shed you choose will determine how portable, firm, or elevated your shed is. You’ve come to the right place if you know you want a storage shed but don’t know which foundation to choose. We’ll lay out your different options and how to build them.
Different Shed Base Options
You may be surprised to find that there are more shed base options than you initially thought. We’ll include a list of the best options to choose from in this article. While there are more aside from these, we felt that these are the best options available based on reviews and research.
Skid foundations aren’t frost-proof or necessarily the best shed base option, but they’re one of the most popular. Although skid foundations are one of the most popular base options for sheds, they’re not technically a foundation. The skids are part of the shed itself and consist of a series of timbers or beams that stretch across the bottom of the shed.
This type of foundation is popular because they’re relatively cheap and easy to build, and they allow you to move your shed if you ever want to do so. If you buy a pre-fabricated shed that you didn’t build yourself, there’s an excellent chance it will come with a skid foundation. However, for a long-lasting shed, you should have a second base consisting of gravel, concrete, or blocks to set the skids on rather than putting them directly on the ground.
Gravel pads typically come out on top in terms of both popularity and the best overall option for a shed foundation. While they aren’t frost-proof, Gravel pads are loved because of how easy they are to install, how cheap they are, and because you can put many different bases on top of them. Gravel also offers excellent drainage as long as your foundation is deep enough.
As mentioned above, gravel is the ideal foundation for skids, concrete blocks, and any other type of base that you want to put between your shed and the gravel. Gravel pads allow you to dig a hole in the ground and fill it with gravel or set up a perimeter of beams or timbers and fill the inside with gravel.
If the only thing you’re worried about has a strong foundation, and you don’t mind the extra cost and work, a concrete slab foundation is the best foundation for your shed. Concrete pads will often require a building permit because you have to excavate the building site. They also tend to be overkill for a small shed such as a garden shed but are ideal for larger sheds, garages, barns, or pole buildings.
Concrete also offers the most support for heavy equipment and heavy items such as tractors, large mowers, four-wheelers, and all-terrain vehicles. However, concrete paving slabs are overkill for smaller sheds and are much costlier and more labor-intensive than most other shed bases. They also offer a frost-proof base if you use concrete footers below the slab.
Concrete Blocks or Pavers
Another excellent shed base option is to use solid-concrete blocks or pavers. Along with skid foundations, using blocks or pavers is an extremely popular option because it is affordable and easy to install. This type of foundation is best used when you set the blocks atop gravel or concrete rather than directly on the ground because the ground will shift over time.
Blocks and pavers are ideal if you need to build your shed on uneven ground. Because pavers and blocks come in many different sizes, you can stack and combine them however is necessary to get a level base. However, we don’t recommend blocks and pavers for every type of shed, as some are too large and heavy for the blocks to support.
Post and Beam
A post and beam base is another excellent option for your shed’s solid, permanent support. A post and beam setup features a series of posts driven into or resting on the ground and beams that connect from one post to the next. They’re an excellent alternative to using concrete piers and provide a more cost-efficient and less labor-intensive option.
You can install post and beam bases in several different ways. You can pour a concrete or gravel pad and have the posts resting on top of them. You can set the posts on pavers or concrete deck blocks, with the posts on the bare ground or your posts driven into concrete footers. If you live in an area where you’re worried about having a low frost line, posts driven into concrete footers are among the top frost-proof foundations.
Post and beam bases are perfect for building your shed on sloped terrain or uneven ground. You can cut the posts at whatever length you need if there’s too much slope to manually make the ground level.
For instructions see How to Build a Post & Beam Shed Foundation on a Slope.
If you like the idea of a permanent concrete base that’s frost-proof but don’t want to spend the money for it, concrete piers are an excellent option. Concrete piers are similar to post and beam bases, but you use concrete instead of wood for your posts. Because of how strong concrete is, you also don’t have to go to the trouble of running beams from post to post.
You should make sure to have enough piers to properly support your shed. It’s best to have one at each corner, plus at least one or two in between the corners if the length or width is greater than 10′. While they’re more expensive and more challenging to install than gravel or skid foundations, they’re cheaper and easier than concrete.
Metal Foundation Kit
While metal foundation kits are a fairly popular option, they’re not one of the better ones. Typically, you can’t use metal kits if you build your shed because they are custom-made by shed companies to fit their pre-fabricated sheds. However, if you’re going the route of buying a pre-fab shed, metal foundation kits are a cheap and easy way to support it. They also aren’t frost-proof or durable.
You can purchase a metal foundation kit from Lifetime.
Plastic Shed Base
Although the name makes this type of base sound flimsy and weak, plastic shed bases are surprisingly strong and durable. They typically get made out of recycled materials, making them one of the most eco-friendly options. Plastic grid foundations are easy to install and snap together, similar to puzzle pieces.
They’re also very affordable, but their best use is with smaller sheds, plastic sheds, or tool sheds. You should also set the plastic grid atop a gravel pad to ensure stability and proper drainage.
What is the Best Base for a Shed?
The overall best base and foundation for a shed depend on its floor and how big it is. If your shed is pre-built or has a wood floor and you want it to be portable, a gravel foundation is a good idea. However, if you have no intention of ever moving your shed and building it yourself, a concrete pad is the best base for the shed.
How to Build a Base for a Shed
A solid shed floor base is critical to extending the life of your shed. The better your base and foundation are, the more structurally sound your shed will be and the more of a beating it can take. Here’s what you need to know about building a shed floor base.
Determine the Type of Base and the Frostline
- The first step of any construction project is to check your local building codes and ensure you don’t need a permit. Building codes will also stipulate how big your shed can be and the different foundation types that are acceptable in your area.
- Once you have all the information you need, the type of foundation you want, and the location of your shed, you’re ready to get to work.
- If you live where frost will play a factor, choose a shed base that you can install on top of concrete footers below the frost line.
- To do this, determine where the frost line is, dig deep holes to get below it, and pour concrete piers periodically around the perimeter of where your shed will sit. Holes should be roughly four feet apart from each other.
- However, if you live in tropical or mild areas, you don’t have to worry about the frost line and can choose a base of your liking.
- You can proceed with the foundation after your holes get dug, and the concrete is poured and has time to cure.
Install the Posts
Your holes should be a minimum of one foot deep after you’ve poured the concrete footers for the frost line. Pour around 4″ of gravel into the hole and pound it solid. Next, take 4×4 wooden timbers and drop them into the holes, making sure they’re square and plumb. Pour concrete around the perimeter of the poles to ensure they don’t move. Cover it with soil after the concrete is solid, and proceed to your next steps.
Cut the Posts and Install Brackets
Determine how high you want your shed to be off the ground. Take a circular saw and a level, and cut each of the posts to form a level base for the shed floor. Next, attach base brackets to the top of each foundation post using wooden screws and a drill. Take 4″ x4″ pressure-treated runners and attach them to each base, forming a wooden frame perimeter.
Proceed to the Shed Base and Floor
Your next step should be to gather all the remaining tools and lumber you’ll need to construct your base and floor. These include everything for the rim joists, the floor joists, the wood frame, and the top plate. All of the wood you use for the floor and base should be pressure treated, durable, and strong. You should use 2x4s for the wood frame and either 2x4s or 2x6s for the floor joists depending on how high and strong you want the floor to be.
Once you have what you need, you can proceed to build the floor frame and set it on top of the runners in the post brackets. You want the frame square with a three or four-inch overhang beyond the runners. Once again, use wood screws to attach the frame to the runners and make sure it’s square.
With the wood frame installed, all left of the foundation is to use ¾” or 1″ plywood and create your floor. Use wood screws and make sure that the floor is square with the wood frame and the runners.
How Many Concrete Blocks for a Shed Foundation?
If you don’t have a frost-line to worry about and want to use the most cost-efficient and easiest-to-install foundation, concrete blocks are the way to go. To determine how many blocks you’ll need, you first must know how big your shed is.
- Start by figuring for one block at every corner of the shed.
- You’ll have to add a block every two to four feet along the front and back of your shed.
- Add an extra block every four to six feet along the sides of your shed.
- Next, multiply the number of block rows you need by the number of blocks in each row to get the total number of blocks necessary.
- Smaller sheds need as few as 4 to 8 blocks, while larger sheds use up to 60.
Are concrete pads frost-proof foundations?
Concrete pads are only frost-proof when you build them on top of concrete footers that start below the frost line and extend to the bottom of the concrete pad.
What’s the best frost-proof foundation?
The best foundation to ensure that frost won’t shift your shed’s base and damage it is concrete piers of wood posts on top of concrete footers.
What’s the best foundation if I get a lot of rain?
If you live in an area that gets tons of rainfall, it’s best to have a gravel pad for your base accompanied by plastic trim pieces, concrete blocks, a skid, or another type of foundation. It’s best not to place your shed directly on the gravel.
As you can see, there are many different types of bases you can use beneath your shed. To choose the right base for you, it’s important to consider the size and type of shed, whether or not you plan to move it, and how long you want it to last. Once you determine these factors, you can choose the right base for your shed and ensure it has a solid foundation to sit upon.