In-Ground Trampoline Installation

Nothing like a good old trampoline. Tons of fun and high risk for injury. :) My sister recently purchased a trampoline for her family and asked me how I installed my trampoline in the ground. For my most recent endeavor, I searched the web for a solution and found very little of value. Because of this, and because of my sister’s request for info, I decided to blog my in-ground trampoline story. Maybe you will find this useful if you are considering installing a trampoline at ground level. If you are not interested in the “History section”, you can skip right to the “Process” section.

History:
When I was a teenager, one of my younger sisters (the same one mentioned above) saved up some money and bought a trampoline for the family (how nice of her). Being a testosterone filled teenager with nothing better to do, I decided we should dig a hole for the trampoline. We did so, and, while it was a “low tech” design, it is still there to this day.

Several years ago, I (along with the help of family) dug another trampoline hole for my own trampoline. We used 2 by 8 pieces of treated wood connected with truss plates at 45-degree angles to hold back the dirt. We also put a green ground cover around the tramp in the shape of a square. The purpose for the ground cover was so that we could avoid sprinkler water on the tramp. We thought this would prolong the life of the tramp pad. It didn’t. The sun is the real tramp pad killer.

Process:
We recently redid our trampoline hole, and this time I think we came up with a nice solution.

I looked into purchasing a kit http://www.trampolinesdownunder.com/pages/aboutthesystem, but the system costs around $700. Um . . . no thanks. My design is similar, but much less expensive. We used Ondura roofing (see image) that we purchased at Home Depot. Ondura comes in sheets that are about 4 feet by 8 feet. The green color seemed like the best option (because grass is green - haha). We used tin snips to cut the sheets into heights of two to three feet. The tin snips didn’t work very well after about three sheets, so, if I were to do it again, I’d look for a better cutting tool.

You don’t want the tramp flush with the ground because the lack of air flow will stifle the bounce. It will also cause the pad to make a “whoosh” sound every time you bounce. I tried to leave around two inches between the outside ground level and the surface of the tramp.

I didn’t pull my trampoline out of its existing hole, but the process should work the same on a new hole. Basically, you need just enough space between the legs and the back wall of dirt to slide in the Ondura sheet. Cover the feet of the trampoline with dirt up to the level where you want the Ondura sheets to sit. Place two sheets side by side into the hole (I overlapped them by about 3-4 inches). With one person holding the sheets in place, the other person begins to drop dirt on both sides of the sheet. On the inside, the dirt will slope up from the center. On the outside, you should stack the dirt to ground level. Continue around the trampoline adding Ondura sheets ahead of where you are filling in the dirt.

I would place all the Ondura sheets before beginning to compact the dirt. Then, using the handle of the shovel, gently compact the dirt on both sides. I say gently, because a nice hard push at this point will force the Ondura sheet to move out of position. You will also need to be careful not to puncture the Ondura with the sharp end of the shovel. The inside of the hole should start to resemble a bowl with the deepest point in the center (at least as deep as the feet of the tramp) and then sloping up towards the sides. Always keep the dirt low enough that you would not be able to bounce and touch it. Continue packing the dirt until the entire area is solid. I would then put grass (either with sod or seed) up to the edge of the trampoline.

*Side Note: Understanding your soil and the level of the water table in your area are important before installing your tramp. I have not had to worry about putting a trampoline in where the water table is close to the surface. The trampolines I have installed were in either rocky soil or sandy ground. The rocky ground supports itself a little better than sand.

Well, hopefully this helps for your in ground trampoline installation. I’ve not spent a lot of time reviewing this post, so let me know if there are parts that are confusing or need to be better written.

Chip