Building a shed can sometimes seem overwhelming, especially when it comes to making the structure level and square. Thankfully there are products you can buy right now at your nearest home reno store that makes leveling a shed base easy.
An adjustable shed base system is a popular option these days amongst shed builders. Relatively cheap and easy to install, these adjustable bases can be moved up or down with the twist of a wrench.
While most must be used in conjunction with a deck block or patio stone, there are also some stand-alone options. Below we’ll go over the most popular options as well as how to build an adjustable shed base.
What Is An Adjustable Shed Base?
An adjustable shed base is a system of threaded rods that have steel plates welded to either end. One plate sits on the ground; usually a deck block or patio stone, and the other plate attaches to the shed base frame such as a skid or floor joist.
There are many different adjustable shed base systems, but they all follow the same general design mentioned above. They allow for the shed to move up or down several inches using a large wrench that turns the nut on the threaded rod. The nut forces the top plate up or allows it to be lowered towards the ground.
Adjustable shed base options can be divided into two different camps: those with shed base spikes and those without. Shed supports with shed base spikes are driven or screwed into the ground and hold the shed up by themselves. The supports without spikes rely on either a deck block, concrete pier, or sonotube to provide a stable base.
Why use adjustable foundation supports? A level shed foundation is difficult to achieve, particularly if you have significant freeze/thaw cycles or clay soil. The adjustable base gives you some breathing room and allows you to build your shed, then make adjustments over time. A non-adjustable base would require jacking, shimming, and other maneuvers, which would take far more time than simply twisting the nut on an adjustable base.
- Level your shed base more quickly
- Adjust shed over time
- Bases are not expensive
- Installation is straightforward
Adjustable Shed Base Options
As I said before, there are lots of options when choosing an adjustable shed base. Below we’ll have a look at the different types and outline where and when you might use it. Remember, many of these must be used with patio stones or deck blocks, so be sure to add those to your potential costs as you plan your shed adjustable base.
1. Adjustable Deck Support
Adjustable deck supports come in two different types: fixed and extendable. Fixed adjustable supports have a top plate that is fixed to hold either floor joists or a beam. Extendable supports have a top plate that adjusts to fit horizontal framing, corner framing, and various widths of lumber from 3” to 7”.
Pylex is one of the big names in the adjustable deck support game, and this adjustable base foundation system is one of their main offerings. It has three main parts: a 4×4 base plate with a steel shaft, a u-bracket welded to a threaded rod that sits in the base plate, and a large nut that allows the top bracket to move up and down on the base.
The manufacturer suggests their product be placed either atop a deck block or a sonotube. The top bracket is designed to fit with either a 4×4 or 6×6 vertical post, depending on the type you buy. Pylex calls them either the “44” or “66”.
While they are meant for vertical post applications, they can also be placed in a pattern to hold horizontal structural components. There are a couple of ways to install a shed base in tandem with these supports. One is to create a series of supports on either deck blocks or sonotubes and run your shed base floor joists through the supports.
If you choose this method, you’ll need to use spacers to make the joists fit snugly in the supports as they are meant for 4x4s. A scrap piece of your joist material and deck board should work.
The other method would be to rest 6×6 or 4×6 skids atop the adjustable supports and then put your shed frame on the skids.
Alternative Installation Option – Advanced
Sheds are heavy. A woodshed can weigh at least a ton – or more. If you have concerns that the narrower shafts of the adjustable supports may not support the load of your shed, then check out this advanced option for using adjustable shed supports.
Using the same deck blocks and Pylex adjustable supports, take the base and turn it upside down. Tape the bottom end of the tube. Twist the base so that its corners sit on the top edges of the deck block. Next, fill the interior and sides of the deck block with concrete.
Once dried, you essentially have a solid concrete block with a perfectly vertical hole in the middle. This gives a significant amount of extra support to the adjustable base. Once dry, you can place your threaded rod with nut right in the hole. The nut will sit on top of the block and can be adjusted just as you would when installing it originally.
2. Adjustable Deck Support – ExtensibleExtensible supports work just like the traditional adjustable supports, but with a key difference.
The top plate of the support is simply a flat plate with four holes in each corner. The u-shaped parts of the support are removable and connect to the top plate with short carriage bolts through the top plate. This allows you to slide the u-brackets closer together if you are using a 4×4, or to slide them outwards if you are using a 6×6.
Additionally, you can also turn the u-brackets, so that they form a right angle. This is especially useful if you want to support your shed at the corners. You can have a bracket holding the outside edge of your shed floor base.
Installing Extendible Supports
Just as you can with the traditional adjustable supports, you can put these supports on deck blocks or sonotubes. The base is reversible, so you can fill your deck blocks with concrete using the technique mentioned in option #1 to provide extra support for these extendable supports.
When connecting the top plates to shed framing, be sure to use 16d galvanized nails or structural screws. If possible, use the four carriage bolts provided by the manufacturer to anchor the bracket to the top plate. For extra-wide stock, this might not be an option, however.
While these supports do have a pretty narrow shaft, they are rated to hold over 2500 pounds. Therefore, if you have a shed base with 8 supports, you are looking at many tons of support underneath your shed structure. Unless you plan to store gold bars in your shed, these supports will provide more than enough stability for your shed.
3. Pier Block Elevated Post Base
Pier block elevated supports are made by Simpson, which is one of the most trusted names in fasteners. It is hard to find other fasteners and brackets other than Simpson at home reno stores. With that being said, this is their version of an adjustable shed base.
Simpson sells their version without a bottom plate. This elevated post base is simply a threaded rod with a u-bracket welded to the top. These post bases come in two versions: one to support 4x4s and the other to support 6×6 posts.
These supports are supported by a nut and washer – sold separately. The washer and nut sit directly on the concrete base, with the washer making full contact with the concrete.
Installing the Pier Block Elevated Post Base
You can use a variety of concrete bases with these supports. While the specs mention using pier blocks, you could also embed them in the wet concrete of sonotubes or other deck blocks that you’ve filled with concrete.
Simpson suggests that you drill your own ¾” hole in an existing concrete pier and thread the rod into it. The shaft must be at least 3.5” deep into the concrete. You’ll need a masonry drill bit and a hammer drill to do this job. Once in, you should be able to twist the rod into place, but it should also be snug.
Just as you would with the other supports, use 16d nails or structural screws to attach your shed base framing to the post base bracket.
These are extremely durable, strong adjustable shed supports. They are rated to withstand nearly 2 tons of weight, making them about 1000 pounds stronger than the Pylex adjustable supports. On the other hand, you have to buy the concrete piers, nut, and washer separately.
While installation might require a bit more work for these adjustable supports, they are a great sturdy option for your shed.
4. Adjustable Helical Post
Another Pylex product, adjustable ground spikes for a shed base, actually screw into the ground via a helical plate welded to the bottom of the spike. They come in various sizes, such as 50” and 30”, therefore you can choose a length that will adequately go down further than your frost line.
The benefit of these posts is that they give you the stability of foundational support but are also adjustable. While traditional adjustable shed supports sit on top of the earth on deck blocks, these are sunken into the ground. As mentioned above, regular Pylex adjustable supports can sit in sonotubes, but these helical posts are a much quicker installation option that is using sonotubes.
Of course, all adjustable supports can move up and down, so why bother with the helical version of the Pylex adjustable post? The answer is that while a traditional Pylex adjustable post can move up and down, it is also susceptible to side to side movement, which the support cannot account for. The helical post negates that issue since it is sunken below the frost line and, thus, will not move laterally.
Installing Adjustable Helical Posts
Installing these posts requires a very long lever, such as a 10 or 12’ 2×6 or greater. Anchor one end into the bracket at the top of the helical post and simply twist into the dirt where you want your post to go. Pylex recommends banging in a piece of ½” rebar as a guide for the post.
The best part about these posts is that you can purchase extensions to make them even longer. If you live in a cold area with a deep frost line, a couple of extensions can make your 50” post much, much longer – and stable. A lateral stabilizer, sold separately, also helps keep the post straight as you screw it into the earth.
5. QuickJACK Pro
A European version of the adjustable shed support, the QuickJACK Pro shed base markets itself as needing zero site prep before installing.
Essentially, Quickjack is offering adjustable shed base spikes coupled with a large support plate. While this should raise alarms for those of you in northern climates, it may be a viable option for warmer areas; however the Quickjack Pro is only offered in European markets at the time of this article.
The Quickjack depends on a large, circular plate and a threaded screw pile. The circular plate is attached to a nut that can move up and down, and the bracket on top of the pile is also held up by a nut. In this way, you can adjust where exactly you want your plate and bracket by adjusting either or both.
Quickjack sells their product based on what size and type of shed you are buying. If you go to their website, you can buy a small “kit” that comes with enough supports to hold up a 4×8 shed or any size in the neighborhood of 30 to 50 square feet.
Additionally, the kits offer screw piles with differing brackets that support all areas of your shed base. Corner brackets for the corners, flat cross plates for intersecting joist/blocking in the center, and t-brackets for sill plate and joist connections.
Will these supports stand up over time? Maybe. If you have level ground and live in a climate that experiences very little to no frost, then they will likely work just fine. On the other hand, if you have lots of moisture in the area of your shed, it may alter the effectiveness of these supports.
Also, while the circular plate acts as adjustable foundation pads, the spike underneath is not very long. Shifting earth would easily move a short spike that Quickjack offers, whether it was related to frost or shifting from dry to wet and back to dry soil again.
Installing Quickjack Pro Adjustable Supports
Using Quickjack as a shed base is probably the simplest option on this list, but also the least durable. First, you need to purchase the right kit for your shed base. The kit will provide you with supports for each part of your base: corners, sides, and the center.
Layout your spikes in the manner dictated by the Quickjack kit. Before pounding the spikes into the ground, screw the circular plate up the threaded rod. This will give you room to adjust the base after you put it onto the brackets atop the spikes.
Place your shed base carefully on top of your supports. Check to ensure all supports are centered on the brackets and plumb. Attach the brackets to the shed framing using 16d nails or structural screws. Then push the spikes down, so they meet the earth. You’ll have to either push or use a hammer to pound them down.
Once the plates are firmly on the ground, simply go around to each support and turn the top nut to level the structure. It’s easiest to start with one corner that is elevated and level to where you want it, then work your way down the other sides ending in the opposite corner. In this way, you will ensure your base is level.
These supports are a great option if you have a small shed you want to support and don’t want it resting on the ground. Stay away from these unless you live in an area with no snow, not much rain, and plenty of level ground to work with.
Once you build your shed, going back to re-level or move it can be a huge pain. As the old saying goes, “do it right, do it once”, and when it comes to adjustable deck supports, that couldn’t be more true.
Pylex offers an easy, DIY solution for either screw or surface adjustable supports. Simpson offers the heavier-duty option but with more prep required. Quickjack is a new player and not yet sold in North America, so unless you are a reader in Europe, you cannot buy these locally in North America.
Regardless of the type of support you use, remember to work with a partner and, as always, safety first! Thanks for reading this article – I hope you found it helpful. Leave a comment below to let me know how your adjustable support shed base project worked out.
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