This summer we tackled the largest DIY project that I’ve ever done in my life. My husband and I and our 3 sons are big fans of the American Ninja Warrior tv show, and last winter I installed gym rings in the rafters of our basement so the kids could swing through the laundry room and get some mid-winter exercise. This was such a hit that more rings and a pullup bar followed shortly after. With our kids starting to outgrow our modest (and rotting) backyard wood jungle gym, along with a trampoline starting to rust… it was time for a new backyard play structure of some kind. Something that could grow with the kids and still be used when they’re teens. So the plan was hatched to build our own ninja warrior structure. This became a massive, expensive and months-long project with (if I do say so myself) stunning results!

Early this year I began researching these structures and eventually came across the website Ninja Warrior Blueprints. I ultimately bought their plans, which gives you a detailed 40 page PDF with descriptions, blueprints, parts lists and a few photos. Admittedly I would have liked these plans to include more closeup photos of how things were attached, and a more clear indication of which items belonged where – because ultimately we modified the plans and didn’t build all of the supplemental pieces. I spent a lot of time identifying which parts were for what and making our own modified list. I also adjusted the layout so that both lanes would be the same length, rotated and flipped it, and I swapped out the 4×4″ posts for 6×6″ posts for extra stability and longevity. Here in Canada at least, the quality of pressure treated lumber is not what it used to be and 4x4s are rarely used for more than decks here. Here’s the modified plans from the top-down and a small preview of what you get with the plans.

The blueprints were useful for planning things but not at all for visualizing what the structure will look like and for having conversations with my husband about scale and what we wanted to add. Since it was still winter and I couldn’t really get out and start building, I decided to learn Sketchup and created a 3d model of our plans. This resulted in a fun scale model that we could rotate around to look at from any angle and get the kids excited.

After consulting my dad (an experienced hobby woodworking craftsman) and my husband’s colleague (the carpentry teacher at the school where my husband teaches) we finalized our lumber and concrete needs and placed an order. It was dropped off in our driveway and moved into the garage in preparation for building. We ordered pressure treated lumber and Quikrete Fence N’ Post concrete. I can’t believe how many bags we needed to order for 9 posts. For each size of wood I ordered one extra, so that we could work around any warped or split boards. This ended up being a very good decision.

Our 6×6″ posts are 16 feet long. And originally the plan was to rent a posthole auger and sink these posts ourselves. But once they arrived it became apparent how insanely heavy these things are. Research also revealed that here in Ontario we need to sink posts about 4′ deep through soil that tends to be full of clay and stones. This was starting to seem like an impossible task. My dad suggested we look into companies that will set the posts for us, and happily we have an existing relationship with the local company Arrow Postholes who’s website I built, so we hired them to do the job. Despite needing to knock down part of our back fence to get their little bobcat back there, the install went so smoothly. They made it look easy and set the posts based on my blueprints. This was a great decision.

From here it was time to really get into it ourselves. For a few days we recruited some awesome friends and family to help out and we got the bulk of the horizontal beams installed. We used 2×8″ boards for all around the outside faces and down the middle. Installed with carriage bolts, this gave the structure some really solid stability and provided the strong foundation for everything to come.

I really can’t understate what an undertaking this was and how appreciated our helpers were. This happened to fall on one of the hottest weeks of the summer. Despite a large tent set up for shade and a pool to jump into as needed… everyone was absolutely boiling and these beams were huge and heavy. I ended up with sore arms and back after each of these days. We found that clamping blocks of wood to the posts to rest the beams on, and generous use of clamps was a valuable technique for safety and to save our arms. Drilling holes for the carriage bolts was a real challenge since we needed to extend the drill bit longer and use multiple bits to finally get through. It’s awkward to apply forward pressure above your head. In hindsight it would be nice to have a taller ladder. Luckily the menfolk had this step in the bag.

After installing the main horizontal beams, some of our helpers cut and drilled holes for the bars – repurposed from our old trampoline. While my husband and I installed 2×6″ cross-beams for the lane of hanging holds. We used joist hangers for these and spaced them evenly. On each one we installed 2 hammock hooks that we would use to clip various dangling holds and items. These hooks are actually a D-shaped ring on a plate rated for 400lbs. Each cross-beam has 2 so that we can install 2 ‘lanes’ of holds. This was an awkward task but we found that pre-drilling holes and the joist hangers made it much easier.

At this point we were starting to put a lot of thought into safety and padding for the ground. Research revealed a lot of pros and cons for various flooring materials – grass, wood chips, sand, pea-stone, rubber, etc. Ultimately rubber would be the best for safety but it will cost a small fortune so we may invest in that for the future. But grass is a close second so we’ll be coaxing grass to grow over time and we also ordered many hundreds of dollars worth of gymnastics pads to go on the ground (on top of the eventual grass). We now have many of these and the safety element is much better.

The kids however, need a way to get up to these obstacles which are still several feet off the ground. So we installed a cargo net and ladder on one end. We also added blocks of wood on the half-way posts to be a rest-stop for when climbers need to pause halfway down a lane. These are very popular. We added handles on these halfway posts as well. At this point the kids (and adults) could really give it a try and we discovered how very out of shape we are! Those early days the kids were excited to even make it halfway across a lane.

Our next major steps were to add a second horizontal beam to the long side facing the rest of the yard – this would provide a larger area to attached holds to later. As well as adding the ‘devil steps’ a series of flat cross-beams that go up an incline. These were very hard to build because we were now getting so high off the round without any proper scaffolding that it was nerve-wracking being up so high. There’s me sitting the top! (We managed to put some boards across the top of the horizontal beams to make a platform to stand on which was much more secure.) The devil steps are meant to hang from with your hands, after going up the salmon ladder on that side. But since we are nowhere near that advanced yet… we added more hammock hooks and hung more hanging holds from these for the time being. We also added a rope climb next to this lane, which has been lots of fun for both swinging and climbing.

The inside of each of the horizontal cross-beams, provides an opportunity for more interesting holds and the ability to link trips together. After much research we added a lane of pig-noses, a lane of wood cliff-hangers (made with 2×2″ boards) and a lane of coated metal safety handles. For many of these we had to replace the included bolts with thick lag screws since we didn’t want them coming out the back side but still wanted really secure fastening. The wood cliffhangers used offset wood screws with washers for extra support. The handles and pig-noses used lag screws. These are quite sturdy and only a bit of flex in the handle and beam they are attached to is observed when an adult hangs and bounces on them. So far the kids cannot make it across the cliffhangers or pig-noses. Yet!

For all of this process, we got the boys (11, 9 & 7y) to help when they could. Whether it was drilling holes, holding things steady or gathering sharp stones on the ground, they were really excited to be involved.

The outer faces of the horizontal beams provided the opportunity to add hand-holds that are larger and more visually interesting. We were aiming for things that could be traversed multiple ways. The first of these was the double 2×8″ beams that made a for a wide area facing the yard and most visible to anyone back there. We settled on pipes in a zig-zag path that could be traversed by hand, with rings, or with plastic sleeves that can slide onto the pipes. These methods increase in difficulty and my oldest has managed to do it by hand and with rings so far! My husband convinced the hardware store to let him take some plastic caps that were randomly on some of the pipes so that we could keep hornets from making nests inside the pipes. First we made a vertical ‘ladder’ of pig noses so the kids could get up to the pipes. When we started working on the pipes, we were so excited and determined to finish that we worked all the way until dark and brought out lanterns so the kids could give it a first try. The next day they really got the hang of them. These turned out really really cool. The kids were already getting drastically stronger.

For the opposite side, my husband found these awesome 4-in-1 ninja knobs made of high-density plastic. They can be traversed by hand, with rings, with pegs left in the holes or with pegs that the climber carries with them and inserts into knob after knob. These were quite pricey and shipping to Canada was brutal, so my husband found a service which will give you a temporary shipping address in the US – we live just across the border. These were absolutely worth the effort. [Edit Sep 2024: The knobs are actually degrading, the plastic inside the hole has come out and it’s flaking off. I now regret this expensive purchase.] We ordered them in blue with green pegs and we installed them on a peaked chevron to give an up-hill, down-hill challenge. It was surprisingly tricky to get the angle right and to work with the heavy 2×8″ beams, but we figured it out. The texture of the knobs is gritty for excellent grip and each one installs with 4 screws. This obstacle is dramatically high and difficult. My oldest can do it by hand so far with an adult spotting him from below.

Continuing to expand on the fun, we added a slackline which was a gift from a friend between 2 trees and one of the posts. This was a valuable addition because it’s more approachable for younger kids and focuses on balance. At only about a foot and a half off the ground it’s also less scary. It gives the upper body a rest and we added an upper line of hanging holds to make it easier and more fun. The kids and their friends have spent hours chasing each other in circles around it. Many floor-is-lava games happening here. We also installed some of the salmon ladder – enough for 2 jumps as well as a removable fire pole where the salmon ladder is since the salmon ladder is so difficult it will be a while until we can really try it. The fire pole definitely builds upper body strength and the kids have been racing each other up. The kids’ record is a 7 second climb!

I’ve been having a ton of fun adding obstacles to this thing. I found some small tires in someone’s garbage and I turned those plus some wood into a stepping obstacle hung with strong polypropylene rope. I then bought some plywood and yellow paint so I could cut out and hang these cheese walls that dangle. This lane is modular and we can add and remove obstacles whenever we want because they are hung with big steel carabiners that come on and off easily. It’s been so fun to brainstorm new things and I definitely have more plans! I feel like my own confidence with handiwork and tools has taken a big jump. I’ve added a mitre saw to my Christmas wishlist!

We still have more to do. The reverse side to the pipes is empty and I’m looking into some plastic cliff hangers that have a lip so they’ll be easier to hang from. The outer beam above the ladder and cargo net is also empty and I’m working on ideas for this spot. I plan to keep making more attachments too – it’s fun to keep it fresh and swap the layout every few weeks. To store all these things I bought one of those popup bike tents and put it beside the shed. It stores all the crash pads when we aren’t using them. I bought a second one that was delivered today and plan to put it beside the first to store all the various attachments that aren’t currently in use.

All-in we are at about $6000-$7000 for this project. Expensive but we hope it will be an investment for out kids’ future. We did our best to build it to last. Our travel trailer is for sale and I’m hoping the money from that will also help cover the costs.

The kids (and adults) are having a blast and getting stronger very quickly (especially the kids). Hands are full of blisters and we’ve bought chalk to help. My oldest can now do several laps across various obstacles without stopping and the other two aren’t far behind. We’ve even set up a 30 days of pullups challenge this month to help us (especially the adults) work on our upper body strength. It’s been fun to see a love of fitness take root in the kids – admittedly we are a video games and TV kind of couple and we wanted to instill values of physical health and fitness into our kids. This has been a uniquely tough and fun project for my husband and I. As a programmer it’s a nice treat to build something that’s very much physically in the world- that you can see and touch. I’m definitely proud.