Building an In-ground Trampoline
An in-ground trampoline is great to have in your yard because they can be safer than traditional trampolines. This is a project that simply takes a normal trampoline and buries it below ground to minimize fall distance, since the main injuries associated with using a trampoline are falling off and hitting the edge or the ground. With an in-ground trampoline, you don’t have the height of the trampoline added to your fall, and this can sometimes make the difference.
You may want to take on this task yourself and it’s more than possible! Building an in-ground trampoline is not difficult but it can be a very precise project. The article below will explain how to do it.
Step 1 – Build the Trampoline
Putting the trampoline together is not very difficult to do, but it has to be built properly. Unbox and arrange all the pieces. Place the frame on the ground upside down and then line up the legs with the holes on the frame. Insert the provided screws or bolts and tighten them. You will need to wait until you’re close to finishing the project before you can add the mat, so just set it aside for now.
Step 2 – Choosing and Preparing the Area
Pick a place in your yard that is level and away from drainage and low-hanging trees as well as water and gas pipes or other utility services. Turn the trampoline frame over in the space and trace it with the paint. Remove the trampoline and place it back on its legs off to the side.
Excavate the area you marked off using a shovel or a mechanical digger. As you dig, remove any debris you may find including rocks, pieces of metal, and roots. The height of the trampoline is how deep the hole should be so that the trampoline sits at ground level. Some recommend leaving a gap of about two to four inches between the jumping surface and the ground to allow for proper air ventilation, but this can be counteracted by installing tubing below the surface to vent the air so that the edge of the trampoline is not a tripping hazard.
Measure the depth of the hole often, tamping down the earth prior to each attempt at measuring. You will also want to make sure it is level.
Also, keep all the dirt your pull out in this process, as you will need it later.
Step 3 – Add Reinforcement to the Hole
It is important to have something to help sustain the structure of the pit’s walls. There are reinforcement systems that you can purchase from trampoline vendors, or you can fashion your own out of 2x4s and sheet metal.
To craft your own support, you will want to attach long lengths of pressure-treated 2x4 lumber all around your trampoline frame using something like self-tapping screws. Place one row of lumber within a foot of the top of the frame, and then attach a second one about a foot and a half below the first.
Next, begin wrapping sheet metal around the frame, securing it to the lumber with screws. This will create a solid base that will prevent any deterioration of the inside of the pit.
Step 4 – Create Additional Air Venting if Needed
Now is the time to add any venting or extra drainage you might need for proper functionality of your trampoline. Air ventilation is needed because without it, your trampoline’s surface won’t be able to bounce as well. Flexible piping can be used for this, starting below ground and stretching to the surface.
Step 5 – Add Gravel and Pack Dirt
It’s finally time to flip the trampoline into the pit. Obviously, you will need help for this, so ask friends and family to help you will this step.
Now you will need that dirt from earlier, as well as a layer of gravel to help pack the trampoline in place. Rake the dirt across the bottom of the hole and pack it hard around the legs of the frame. Then, add several inches of gravel. This will add weight for keeping your trampoline grounded and it will promote better drainage in the pit.
Step 6 – Finishing the Project
Attach the mat to the trampoline frame with the provided springs and secure the protective cover around the springs. With this, your trampoline is finished!
For added protection, you can choose to install safety netting, or you can cover the ground around the area in a soft surface, such as rubber mulch.