Since we had a limited budget on our backyard project, my cute hubby, AKA Awesomeness,
designed our inground trampoline plan. Dan had searched online for days. A good tutorial was no where to be found. In fact, we were both astounded to find that the CHEAPEST DIY kit is more than $600.00 (and this didn’t include the cost of digging the hole). Plus if you have a professional landscaper come and do the project, the cost was around $1500.00. Um…no way.
Dan conglomerated his own plan with tidbits gathered from several sources. A good friend Jeff Poulton let us come and check out his design. Dan made a few modifications of his own, and off we went to buy the supplies.
Eight 2X4X12 of pressure treated wood
Four 4X12 sheets of roofing sheet metal
Self tapping screws
16 cinder blocks with u shape groove
Tamper (to help compact your dirt)
First things first, Step 1: Dig your hole. We had our landscaper include digging the hole for our tramp in our landscaping. Our ground is FILLED with rocks. After attempting to dig holes in our backyard for trees, we knew that digging an entire trampoline hole was out of the question. This cost approximately $150.00 to have the landscaper dig the hole and haul away most the dirt.
Sidenote: You will need to save some of the dirt for later. So, don’t get rid of all of your dirt.
The hole needs to be one foot larger than your trampoline’s circumference. For example, if your trampoline is a 14 foot trampoline, you need a 15 foot hole. Kapeesh!?
Advice: Make sure the frame fits into your hole before continuing to the next step. We had to manually shovel the sides of our hole for several hours before ours would fit.
Next, level your trampoline. Your trampoline needs to be completely level in the ground. To accomplish this, we used cinder blocks with a U shaped groove in them for the trampoline legs to rest in.
We used four cinder blocks per trampoline leg. Dan was careful to level each section of the tramp by placing a long 2X4 across the top of the tramp with a level on it. This allowed us to make sure that the tramp was completely level when we finished the process. Each cinderblock was dug down and secured into place with the surrounding dirt.
Tip: When putting a trampoline in the ground, you need to leave enough room for the air to escape. We wanted our tramp to be four inches off the ground to create a channel for the air to flow. Most of the tutorials we read said to leave at least 2 inches of leeway. We wanted our trampoline to have as much bounce as possible, so we left it 4 inches above ground level. If you do not do this, your trampoline will lose bounce because the air will have no where to escape.
Next, take the trampoline out of the hole. we took the trampoline frame out of the hole to begin construction on the surround structure.
First, take pressure-treated 2X4s and cut them on 22.5 degree angles. Attach each 2X4 section to the leg of the trampoline section by using self tapping screws. Continue all the way around the trampoline.
Install a second layer of 2X4s it should be installed 12 to 16 inches beneath the top layer. The 2X4 frame is attached to the trampoline legs to help create a supportive barrier for the surrounding dirt in the ground.
Next, begin screwing your sheet metal to the 2X4 frame. Four 12 foot lengths of sheet metal was used to surround the 14 foot trampoline. Each sheet overlapped the next sheet by about two feet. This prevents the need to cut the sheet metal. Start on one side of the trampoline and bend the sheet metal to fit securely along your 2X4 frame.
The top of your sheets should be about 4 inches higher than the 2X4. This allows enough metal to fold over the top of your 2X4 and screw it securely into place on the inner side of your frame. This prevents any sharp edges from sticking up.
Here is a picture of how we did the corners of each leg. We used tin snips to cut a slit into the metal and folded each side down and screwed it into place.
Next, gather a few strong helpers to assist in placing your tramp back into its hole. Make sure that each leg is back into the cinder block groove perfectly. Double check that your trampoline frame is level.
The last step of installing your inground trampoline system is to back fill and compact your dirt on both the outside and inside of your trampoline frame. This will prevent your dirt from caving into your trampoline hole. The outside dirt should be level with the ground. The dirt on the inside of your tramp should slope toward the center of your trampoline. The dirt on the inside of the tramp needs to cover at least 1/3 of your sheet metal frame. The dirt on the inside and outside helps your tramp to stay in place while you jump.
Sidenote: If your trampoline is in the middle of your lawn area, you will need to take extra precautions to ensure proper drainage in the bottom of your hole. We did not have to worry about this step because our sprinkler system does not affect the area where our trampoline sits.
It is SOOO much fun! The kids love it…and so does my dog Sugar.
$150.00 to have the landscaper dig the hole and haul the dirt plus $150.00 for the supplies =
Update: 10/8/2012 I have had a lot of questions about water filling up in the hole for our trampoline. We haven’t had any problems with this personally, but we specifically put the tramp in a location in our backyard that does not get hit by any sprinklers. We also live in a dry climate that doesn’t rain a lot. But, we have had a few instances that my husband accidentally left our hose running for hours and hours filling up our pool next to it which overflowed the pool and filled up the trampoline hole. This has happened three times and the structure has stayed completely in tact. We did pump out the water with a water pump and hose within a few hours though. I hope this answers the questions out there about water and our in-ground trampoline!