If you are planning to build or add a garden shed to your backyard, the most important step is to build a firm foundation for it to sit on.
A good paver shed foundation is the perfect base for your shed and not as hard to build as you might think.
Since building a paver shed foundation involves a certain amount of hard labor, it is always good to know just how much work you are going to be involved in.
The good news is that unless you are building a massive shed that is more like a barn than a shed, you should be able to complete this project in a weekend, leaving you with a little time at the end of each day for an ice-cold beer or two. On top of this, once your foundation is complete, it will be immediately ready for use, unlike concrete that needs time to cure before it can be used.
Before you start building your garden shed or laying the paver shed foundation, you need to take a good look at the ground in the area you plan to install your new shed. There are a few things to be taken into consideration before you choose your final location.
If at all possible choose an area that is already reasonably level. Not only will this make building a level paver shed foundation much easier, it will take fewer materials and less time to build.
You should never build any type of foundation on ground that does not drain well. Ground that is continuously wet or subjected to flowing water is only likely to erode potentially causing significant problems further down the line.
No matter how you plan to install the pavers, try to avoid ground that is simply too hard to dig in or has a lot of rocks just below the surface. All you will be doing is creating more work for yourself or putting yourself in an almost impossible position.
It should go without saying that you should not pick an area of your yard or garden where the ground constantly remains wet and soft. At least if you don't want to see your paver shed foundation and shed to tilt into the ground.
The next good thing on our list is that pavers are very simple to find and come in an incredible array of sizes, shapes, and colors. You can go for the basic square concrete colored paver or step up to colors and patterns that extend beyond the walls of your shed to create a patio.
For the most part I prefer to use pavers that are 2 inches thick and 12 inches square. They are more than strong enough to support the shed when you build a proper paver shed foundation. At the same time, they are light enough for you to handle without too much strain. These should be readily available at your nearest discount hardware superstore or local garden store.
While you could simply lay the pavers on flat ground and call it a foundation, this is really not the best idea. But if you are going to build a paver shed foundation that will not only support the weight of your shed, but also last a lifetime, you will need a few tools and supplies to get the job done. These include:
Since your new paver shed foundation must be built strong enough to last for many years, every step of the building process has to be completed carefully and exactly, starting with marking out the space you plan to use.
To do this mark out each side of the space forming a square. The easiest way to make sure all four corners are square is to measure the distance between each pair of diagonally opposed corners. If they are the same, your corners are square. This method will work for both square and rectangular shaped foundations.
Now that you have the area needed for your foundation marked out, it's time to get started with the fun part. So, grab your favorite work gloves and shovel and start digging. You need to dig the area to a depth of approximately six inches. This will give enough space for the gravel base, the sand and cement filler, and the pavers, leaving them at or just above ground level.
Once you have the soil dug out to the appropriate level, it needs to be compacted. Break out that rented vibrating compactor and go to town. Depending on the size of your foundation, this shouldn't take very long. However, it is a very important step as your foundation needs a firm base to stand upon.
The next step is to add a one-inch layer of gravel to the hole. Be sure to use either 21A or 21B gravel as it contains fillers to help fill in the air gaps between the pieces of gravel providing you with a much firmer base.
Once again you need to use the compactor to pack the gravel in place and create a smooth flat surface. Be sure to check your gravel layer using the 2×4 and spirit level to ensure it is perfectly level before proceeding to the next step.
Mix together the sand and cement and then add a 2-inch layer of this mixture to the gravel. Smooth out the sand and then compact it to form a tightly compacted layer that is perfect level or as close as you can get to it. Making sure each layer is level is vital to the finished product. If one layer ends up being off kilter then every other layer you add on top of it will be off as well. The final result will be a shed that sits tilted and may end up being damaged.
Lay the pavers in the appropriate pattern covering the entire area and check each for level with the others. If you find any that are not level, you can use the rubber mallet to tap them down at each corner until they are level. Take your time with this step as any paver that happens to be out of level might crack or break once the shed is put in place, leaving a weak spot in your finished foundation.
Whether you decided on the plastic or metal garden border, take it and install it around the outer edges of the pavers. It needs to be placed as close as possible to the pavers, any gap only leaves a place for weeds to grow. Anchor the border to the ground using the spikes provided with it or stakes you have purchased separately.
Image courtesy of Pinterest
Spread a layer of the cement and sand mixture used in the foundation over the top of the pavers. Use a broom to spread the sand into the gaps, filling them in until they are flush with the pavers. Using your garden hose and a fine mist nozzle, lightly dampen the entire surface of your new paver shed foundation and walk away.
The water will cause the blend of sand and cement to solidify, permanently holding the pavers in place and creating an exceptionally strong foundation. It will also seal the gaps between the pavers, helping to keep water, ice, and snow from getting under the pavers and causing them to lift or crack. If you don't do this step, your foundation is likely to fail earlier than it should.
There is a fair amount of work involved in laying a paver shed foundation. However, when you are done and sitting back looking at your new foundation, you will find all the hard work more than worth it. Of anything you can do when building your foundation, making sure each subsequent level is as level as you can possibly make it is the most important.
A tilted shed may have doors that don’t open and close properly, windows that won't work, and poor water drainage. Take your time with every step and you will have a paver shed foundation that might just outlast a shed or two.
THE MOST POPULAR FOUNDATION material for a shed is gravel. It's easy to work with, lasts virtually forever, is environmentally friendly, and most of all a gravel foundation will provide exceptional support for your shed.
More importantly, most of today's shed manufacturers recommend you build a gravel shed foundation before they deliver your shed to you. Here are three very important reasons why you should plan on building a gravel pad for your new shed:
One of the reasons a gravel foundation is one of the most popular choices for garden sheds, is that it allows you to spread the weight of your shed and everything it in over the surface of the entire foundation. Other forms of shed foundation such as concrete piers focus all of the weight on smaller areas putting more stress on the framework of your shed, increasing the risk of significant damage.
Even if your backyard is not level or has a small amount of slope to it, a gravel pad gives you the opportunity to create a solid level base upon which to place your shed. By using a wood frame, you can overcome a reasonable amount of slope.
Concrete piers, wood frame foundations, even concrete slabs can raise the floor height of your shed more than you want. Trust me, there is nothing worse than trying to get a lawn mower or other heavy items in and out of a shed that is sitting too high. A gravel shed foundation lets you control the height of your shed and can even let you put your shed at ground level (or at least only slightly above it).
The next major decision is do you build retaining walls to hold the gravel in place or do you go crazy and make your foundation free form?
As we go through the rest of the process, I will go over the benefits of both forms of pad. Each has their own unique features and benefits. Some of this decision is based on the space you have to work with, the type of gravel you plan to use, and the quality of the ground in your backyard.
Let's face it, to most of us, gravel is nothing more than a bunch of crushed up rocks. And while to a certain extent this might be true, there is more to gravel than meets the eye. Gravel comes in a wide range of types and grades, each of which has their uses. There are two main categories of gravel:
Image courtesy Hacker Services LLC (ping pong ball used to show relative size)
There is little difference between these two types of gravel are minor, but for a gravel shed foundation, the 21A variety is the better choice. Often referred to as “1-inch crusher-run gravel” both of these types of gravel have other fine materials mixed in with them. This material helps to fill in the gaps between the larger gravel pieces making it a more stable foundation that will not settle once your shed is placed on it.
Image courtesy Hacker Services LLC
Although these grades of gravel can be similar in size to 21A and 21B, they do not contain any fine materials to help fill in the gaps. This means there is nothing to help hold the gravel in place leaving it to shift around rather than settle into a firm foundation. On top of this, once you place your shed on the foundation, the gravel can still move around, allowing your shed to sink into the ground. This can also cause your shed to become unlevel, which can cause damage to the structure.
Image courtesy thecoverguy.com
If you decide to build a retaining frame around your gravel shed foundation rather than go with a free-form foundation, it is important you use the right type of lumber for the structure. The temptation might be to use standard lumber such as 2x6s to save money, but this is a bad choice. You may also be tempted to use creosote coated lumber such as old railroad ties. As long as you have no intention of growing edible vegetables or fruit within 50 feet of your foundation, this might be okay.
The problem with this is that creosote contains a range of toxic chemicals that are known to be hazardous to your health. The reality is that you really shouldn't use this type of lumber anywhere near your garden. Standard lumber is not strong enough, nor will it (as I found out the hard way) last very long once you bury it in the ground.
The best choice for building the framework around your gravel shed foundation is pressure treated lumber such as 4x4s or 6x6s. Not only will they provide you with a much stronger framework, being pressure treated will help ensure they last for many years without rotting and allowing the gravel to spread out, letting your shed down gradually.
If you plan to build a framework out of timbers, they must be anchored in place before you pour the gravel into your form. If you plan to use a single layer of timbers, you can use lengths of rebar to secure them in place. However, if you need to use more than one layer of timbers, you should use galvanized spikes.
These are available in a variety of lengths to meet your needs at your local hardware superstore. Be sure to buy spikes that are long enough to go through the number of boards you plan to use and then at least 12 inches into the ground to ensure the timbers stay in place.
Just like any other major project you plan to undertake in your garden, there are a certain number of tools needed to build a gravel shed foundation. Among these are:
Now that I have gone over the basics regarding the materials you are likely to need, the next step is to go over building your gravel shed foundation one step at a time, starting with building a retaining wall.
In order to determine how much timber it will take to build the retaining wall, you need to know the overall size of your shed and then add three feet to both the width and the length. This will provide you with enough room for your shed and an extended footer around it to help keep water from getting in it.
Start by marking one corner of your shed with a stake and then mark the other three with stakes. Be sure you have added the required extra space. One way to be sure the stakes are set at the right spots is to measure diagonally between pairs of corners. Much like an equilateral triangle, these measurements should be the same.
Using level find the lowest corner of the ground you plan to use and cut a trench into the ground that goes all the way around the perimeter of your shed. Bear in mind your timbers should be inside the lines created by the stakes you have driven into the ground. (Be sure you use the level to ensure the trench is perfectly level all the way around.
Start out by laying your first layer of timbers in the trench. Next drill several holes through each board and secure them to the ground using rebar or galvanized spikes.
Wherever necessary, add in extra timbers offsetting each corner in much the same manner used in the construction of a log home. This will help to keep the timbers in place. Now secure the timbers together using galvanized spikes spaced out every two to three feet driven into the timber below.
Now comes the fun part, you have a hole in the ground inside the timbers for your gravel shed foundation, the only problem is that it is still full of dirt.
Grab a shovel a pair of gloves and a wheelbarrow to haul away the extra soil.
Depending on the size of your shed, you have a lot of soil to remove. So, put on your leather gloves, grab that shovel, and put it to work. You will need to remove enough soil to lower the level of the ground inside the frame you just finished building until it is at least four inches lower at its highest point below the top of the highest timber.
Finally, it's time to add in the gravel. Be sure you are using 21A or at least 21B gravel. Pour in no more than a 4-inch layer and then use the vibrating compactor to compact the gravel firmly in place. This ensures it won't continue to settle once you have your shed in place.
Use a “screed” (which is a fancy name for a length of wood that reaches from one side of your timber frame to the other) to level the top of the gravel shed foundation. The screed will help reduce the high spots in your gravel by moving the excess gravel into the low spots, filling them in.
Continue doing this until the layer of gravel is level with or slightly below the top of your timbers.
You have just finished building your first gravel shed foundation. Now all you need to do is install your shed and fill it with everything that goes with it.
The only time you should consider building a free-form foundation for your shed is if the ground you plan to put it on is perfectly flat. If you try to use this type of foundation on sloping ground, there is the distinct possibility that the ground under your foundation will erode out from underneath it.
No matter whether you plan to build your free-form foundation on flat ground or a slope, be sure the gravel pad you create is approximately 18 inches bigger on all four sides than your shed. Doing this will allow for a certain amount of corrosion to occur without affecting the stability of your shed.
On a level piece of ground, mark out the corners of your gravel shed foundation allowing for at least 12 inches on each side. Thus, if you have an 8 x 10 shed, your stakes should be set to create a space that measures 10 x 12 feet.
Grab Your Favorite Shovel
It's that time again, grab your gloves and favorite shovel. Remove the top four inches of sod and soil from the space between the markers.
Using a number of 2x4s build a temporary framework around the sides of your foundation hole and stake them in place. You can use the stakes and timbers to create a level frame and set the height of the foundation.
Fill the hole in with gravel and use a screed to level off the gravel.
Use a vibrating compactor to compact the gravel add more gravel to the foundation until you have a pad that is perfectly level and well compacted, then remove the temporary framework.
Once again, congratulations you have built a gravel shed foundation ready to install your new shed in place.
Here's a quick video of the process of preparing a gravel pad for your shed.
There are a few important notes you should be aware of before getting started.
Building a gravel shed foundation does involve a fair amount of hard work. But, the most important thing you need to keep in mind, is that whether you build a framed in foundation or a free-form one, it has to be as close to perfectly level as possible before you put your shed on it. If not, you face the possibility of soil erosion that could end up damaging your shed. I hope this information helps you create the perfect gravel foundation for your garden shed.