This is very debatable and for good reason. A shed base needs to be high enough off the ground to have proper airflow to prevent future damage from occurring. Thus we will be looking into the hows and the whys within this article on how to elevate your shed and with which materials.
A Shed does not need to be elevated off the ground by law, however, the base of the shed needs to be sufficiently ventilated to prevent rot. Ventilation helps get rid of all the moisture from under the shed and keeps it as dry as possible to avoid mold and rot from setting in.
Every method has its pros and cons, but here are a few of the most trusted ways to elevate your shed and ensure proper airflow.
Type Of Shed Base Joists
There are a few different types of shed bases, some have small joists, and others have big joists. Then there are sheds consisting only of walls and a roof. Therefore, the shed will be placed directly onto the gravel or concrete pad that was laid for it.
These sheds are normally built with some form of plastic for weathering purposes. But they tend to be very small and you can’t store much more than your garden equipment.
Bigger sheds like lumber or metal sheds should include a shed base, so you’ll need to make sure that the joist sizes match up to the shed base you’re planning on purchasing/building.
Depending on what you’ll store in the shed, make sure the joists of the base are strong enough to support its weight without bending the base over time.
To make sure this does not happen, you will need to get the correct size joists to support the weight you are intending on storing in the shed.
This is very important for ventilation if you are going to elevate the shed base. If the shed base is not properly ventilated, it will start bending because of moisture that is softening the lumber, causing the weight to bend the base.
This will then restrict the airflow even more and lead to rapid moisture build-up, which in the end leads to dangerous molds and wood rot.
Shed Base Ventilation
There is no set rule for how high the shed base should be elevated off the ground. The key here is to have enough airflow to keep the floor dry to prevent any moisture build-up that will cause any problems in the foreseen future. Of course, this is in addition to any wood protection brushed onto the floor.
Some shed bases are framed, which will restrict the airflow underneath and can lead to mold and/or rot. This is treatable, but when the shed base is framed, it is difficult to detect it early before the rot sets in.
Ventilation under your shed is important as it will help keep out the moisture preventing a build-up of mold over time that will at the end of the day lead to a lot of repair work in the future.
In this case, I would suggest installing vents on the side of the shed base. This will allow for sufficient airflow under the base and will keep it dry.
Another type of base that offers a great amount of ventilation is a raised timber frame base. I believe these offer the most efficient ventilation for sheds, especially if you are planning on building the shed on an uneven surface.
Using a raised timber frame base, you will need to use either a quick jack system or a ground screw system. Both these systems make things a lot easier to get the base level and adjust the height up and down if required.
This will help allow sufficient airflow under the base and reduce the chances of any moisture hanging around.
Materials Used to Elevate Your Shed
These are all great materials to elevate the shed base:
- Solid Concrete Blocks
- Deck Blocks
- Skid Foundation
- Plastic foundation
- Timber posts and beams
For uneven ground, I would suggest these two methods, they are easy to install and use.
- Quick Jack System
- Ground Screw System
Landscape and Conditions
This is another important factor to look at if you are going to elevate your shed. If you are in an area where the ground is soft, you will want to factor in that the shed might sink slightly and start leaning over time as it sets into place.
If the area receives a lot of rainfall every year, you might want to elevate the shed a bit more. Not too much, just enough to prepare for any floods that might make their way through the property and cause damage.
Moisture is the biggest enemy of a shed, so when selecting the materials that you’re elevating the shed with, always consider the landscape and conditions where the shed will be built.
This can save you a lot of time in the future when maintenance time comes around, and the chances that you will run into any major damage to the shed are minimal.
How to Fix Your Sinking Shed
This can be a very challenging project, as the shed is already on top of the original foundation. This happens when the ground that the shed was built on is not stable and solid enough to support the weight of the shed. That’s why you need to keep tabs on how much you’re storing in the shed. It adds up quickly. Heavy rainfall is also a large contributing factor to a sinking shed.
Your shed is starting to sink, and you want to fix this problem. The first thing you’ll need to assess is the bottom of the shed. As said, a lack of proper airflow under the shed can lead up to mold and rot.
If there is any mold or rot on the lumber, try to see whether it will be possible to jack up the shed, because you will need some space to work when stabilizing the shed foundation.
If all is well and there is no visible mold or rot on the shed, you will need to have a jack handy, preferably a bottle jack, as you will be jacking the shed up and need space to do the work. Place a paver on top of the jack and on the bottom of the jack for stability.
When you jack the shed up, make sure to not go too quickly or too high. You might do more damage to the shed by twisting the structure as you are jacking it. So jack it up a little on each corner until you’ve reached your desired height.
Now that you are done with the prepping work, it’s a question of what material to use to stabilize the sinking shed.
Gravel works great to drain water that could pool up or erode the ground underneath. It’s not expensive and easy to throw down yourself.
Concrete is another option that you can use to avoid the shed from sinking again. After you have jacked up the shed, all you need to do is dig a square hole at each of the corners of the shed and fill it with concrete or place concrete blocks and make sure they are level before lowering the shed back down on them.
If needed, try to make the concrete squares that you will be pouring slightly higher than the ground. This will make it easier to work on the shed in the future.
As we now know, there is no set height to build your shed base. However, it needs to be properly ventilated to keep the ground as dry as possible and avoid wood rot in your shed.
So I would recommend making the base at least 4 inches high from the ground. This will allow for the proper amount of air to circulate under most sheds.
If the shed base is framed, remember all you need to do is to install vents all around the base to have the correct amount of ventilation.
For an uneven surface, e.g. if your shed is built or being built on a hillside, there will be more than enough airflow to keep the moisture from building up. All that you need to worry about is the end of the base of the shed closest to the ground.