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.
Supplies List:
Eight 2X4X12 of pressure treated wood
Four 4X12 sheets of roofing sheet metal
Self tapping screws
16 cinder blocks with u shape groove
Tools:
Shovel
Level
Tin Snips
Hammer
Drill
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. 
Total Cost:
$150.00 to have the landscaper dig the hole and haul the dirt plus $150.00 for the supplies =
$300!
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!
Your husband is Awesome! That is a great idea and he did a awesome job. Post pics of the kids on the trampoline, please!
i like it! i've never seen this before – is it just for safety?
Nice idea! Just wondering what keeps critters from living under it?
I had no idea there was so much involved for an inground tramp! Makes total sense now, but I thought you just dug a hole! Silly me.
So how many toys are in the tramp's tummy by now?
My Husband and I are no where close to doing this project but I am so glad that you posted about it. I never would have thought about all that goes into it! It's so much more than digging a hole!
wow, that was a big job! I don't think I could own a trampoline though. My dad is a personal injury lawyer, and I have seen way too many broken legs and injuries! But my husband loves them..so we will see. Excited to see the back yard all finished!
Wow, great tutorial. I've seen trampolines in the ground before and you are the first to address it and post a tutorial. Thank you very much for sharing the knowledge with me. Jackie
thanks for posting this…. I had no idea…. I always thought you just dug a hole and plopped the trampoline right on in…. looks fantastic and super fun!!
Nice job, Dan!! (again)
That's awesome!
Thanks for this post! I'll have to show my husband. We've been seriously talking about getting a trampoline and would love to have the in-ground type!
This is a great idea!
http://gingersnapcookie.blogspot.com/2011/05/welcome-to-trampoline-101.html
We've had our trampoline like this for years and love it! We get leaves under there in the fall but they compost over time. You will enjoy it!
Great idea.
Oh my goodness – wonderful! Thanks so much, we'll definitely be doing this at our new house. Love the cost breakdown and photo instructions! found you on pinterest.
Great idea, it is amazing how many get injured falling off these things. When landing from the height these things are off the ground. My kids are almost grown up, so no need now. But I think it is just awesome. If I were to have that done I would probably put chicken wire on the 4 inch gap to keep toys from falling in or even legs, but mostly to keep critters out!!
We just did this, I wish i would have read this first!!!! We did it a harder way and put the dirt all the way to the top so no air comes out. OOOOPSS!
Wow! I want one!!!
This is a very thorough job! I have to say, with our soil (thankfully less stony than yours and with enough clay content) I was able to just dig a hole and sink it and I must admit, I didn't leave a gap at the top and the airflow has not been an issue.
You can see the results here!
http://littlegreenfingers.typepad.com/little_green_fingers/2009/02/how-to-create-a-sunken-trampoline.html
thank you so so so much for posting this. My husband just told me NO on an in the ground tramp because of the cost. I bet he'll change his mind now.
That is the most ridiculously ingenious thing I've ever in my whole life seen. Thank you for sharing. I have added this link to my bookmarks so I can talk my (completely NOT handy) husband into doing this for our almost 10 year old.
What a great tutorial. Thanks for all the hard work! Are your kids just the happiest kids on the street?
This is a great tutorial!
We just picked up a nice trampoline at a garage sale yesterday. My kids are still little and having them that high up and jumping around makes me a little nervous. I wanted to put it in the ground, so naturally I did a little poking around and also found that $600 kit. Sorry, but no. This looks awesome, and will also help with durability I would think.
Thanks for taking the time to share!
I broke my right arm falling off a tramp – unfortunately the way I fell with my arm extended backwards and my wrist bent, being low to the ground wouldn't have prevented it – plus, my brother through me into the air WAYYYYY over his head with his jump, so I was still pretty high up… and I was 16 and more of a daredevil than I am now! A few years later my brother tore his ACL jumping, not falling, so there won't be any trampolines for my kids. But I like how this is less conspicuous. Down in the ground and out of site! Great job.
kids can get hurt hiking riding a bike swimming etc.. but teach your kids how to do them safely and let them enjoy life not restrict them from things that could hurt them. Kids fall off monkey bars and etc all the time. I Say let kids jump they love it just try to make safety rules!! I love my tramp in the ground it's awesome!!! thanks brooke
How do you keep wildlife from making that area under the trampoline their home?
Great job you have made in your garden. Congrats!. Berg Toys has a model "Berg Toys InGround" specially designed to put down in the ground. And for the lazy ones they can buy the safety net.
I wrote (in spanish) how to sink a trampoline in a diferent way.
http://topludi.wordpress.com/2010/11/24/como-enterrar-una-cama-elastica/
I was just about to give up on installing ours this way… Until I read this!!! You guys made it look so easy.
I saw one of these on The Novogratz's show and thought it was so nice because the main reason I wouldn't get a trampoline was because I was afraid of someone falling and breaking something, like my cousin's daughter did. I saw how much the in ground one's were and thought we are never going to have a trampoline, thanks to this tutorial I think we will!
Very nicely done!
Might I add that it may be beneficial to paint or do some other sort of rustproofing on the frame of the tramp before burying it. That frame looks like it's still doing a lot of work structurally, and adding a layer of protection besides the galvanization that's already on the frame and metal paneling would be beneficial because being in contact with soil dramatically accelerates corrosion.
It also could be better to use fiberglass instead of metal paneling… although that would most likely make it more difficult.
The 2x4s should also be rated for ground contact… or at least green treated. You did a FANTASTIC job… but I think that these little-bitty changes might add to the longevity of your project.
Hello, was just wondering, do you need a special trampoline or can you just have a normal one?
I'm jealous–ours is above ground.
I love the way it looks. You husband did a wonderful job. I agree with the comment that kids need to learn safety rules. My oldest daughter fell off the monkey bars and broke her wrist, my middle daughter broke her arm at the elbow playing soccer. So far no injuries on the trampoline and we've had it for 3 years.
Linda
mysewwhatblog
that looks amazing! my hubby can barley build an ikea bookcase so doubt we'll attempt this but it looks great!
@Daisie Edgerley
It's just a normal plain old trampoline. Hope this helps! Good luck!
What about the hole filling up with water when it rains? My husband was worried about masquitoes?
I think this is an awesome way to put in a trampoline. Much safer than regular. I think there could possibly be water issue in South west Washington. We can get a lot of rain some winters. So I think it just means use common sense.
Thanks a ton for this post!!! I have been combing the internet for a long time in search of great instructions and am very excited to have stumbled across yours. You guys did a marvelous job! I will be making mine this summer and you and your awesome hubby will be a great resource
Thanks
Goran