How to Make a DIY Zipline in Your Backyard

Kids love ziplines, now they can have it at their own backyard! It might take a day or two to build it, but can you imagine all that fun they’ll have for years! You’re not exactly flying through the air, but you can get a lot of airtime. And all those memories created for years to come. Since we have several large pine trees in our backyard, I decided to build a DIY zipline for kids.

Few fun facts about ziplines:

• The longest zipline in the world is in Puerto Rico, reaching 7,234 feet long, and 1,200 feet above the ground!
• In Hongdae, China children use a zipline to cross a wide gorge when going to school and back. 
• The world’s fastest zipline reaches a speed of 100 mph! Located in the mountains of Wales, UK.
• The longest and highest zipline in the US is located in New York state, reaching a speed of 50 mph. 

You also might be interested in DIY Cornhole Boards and Cornhole Bags for your outdoor projects.

Disclosure: Some of the links on this page as well as links in “tools for this project” and “material list” sections are affiliate links.

Step 1 – Determine the Distance and Size of a Zipline

First, determine what size cable to use for your zipline. To figure out the thickness of the cable you need to know the total length of the zipline from point A to point B and the weight. 

There are many websites out there that show how to calculate the thickness of cable and how much weight it could support. But in general, if the length of your zipline is less than 200 feet, you could either use 3/16″ or 1/4″ cable. Both 3/16″ and 1/4″ cable can withstand up to 250 lbs of weight. 

In our case, we have few pine trees in our backyard and the distance from the farthest two trees is about 80 feet. I could have used 3/16 cable, but to be on the safe side I bought 1/4″ cable for the zipline. Having stronger cable is a plus since adults would love to try going on a ride as well.

Step 2 – Stretch and Cut the Cable with an Angle Grinder

Stretch the cable on the ground and loop around the trees to figure out the total cable length that you need. Using a grinder, cut the cable to the correct length. Make sure to cut the cable slightly longer, just in case. You could always cut it shorter once everything is installed. 

Step 3 – Make Protection Blocks for the Tree

Remove any branches that might be in the way. You don’t want kids to be scratched by the branches while riding the zipline. When wrapping the cable around the tree, it’s a good idea to place protective blocks under the cable so that cable is not touching the tree. These blocks will protect the tree from damage that stretched cable might cause. Depending on the size of your tree, you might need a different amount of blocks then what I installed. The diameter of both trees in our backyard is 20″, so installing three blocks per tree worked out well.

Take 2×4, preferably treaded wood, and cut six pieces to 10″ in length. If you have a bigger tree you might need to add more blocks. Then rotate the blade of your skill saw to 45″ degrees and cut a 1/2″ deep groove in the middle, just wide enough for the cable to be placed in. Do that on all six protection blocks. 

Step 4 – Attach Protection Blocks Around the Tree

Before attaching the blocks to the tree you need to figure out the height of your zipline. The zipline needs to have a slope in one direction. For slopes that are 6% (6 feet drop per 100 feet of distance), you will need to have a bungee brake. For slopes that are 3% or less (3 feet drop per 100 feet of distance), the bungee brake is not required. Do not exceed a 6% riding slope. High-speed collision with end point may cause injury or death. 

The elevation I chose on the first tree was 11 feet from the ground and the second tree 9 feet. I wanted the zipline to be slightly higher and have a longer seat attachment. I figured it would be much safer for kids not to be close to the trolley wheel, especially when they are riding. 

Since my kids are still small, I installed the zipline about 3% slope for safety. The ride is not very fast, but they still have a lot of fun. At this slope, the bungee brake is not necessary.

Once you figure out the height of your zipline, attach two protection blocks on the left and right side of the tree and one block in the back using 2 ½” wood screws. Make sure to position the blocks on the tree so that the grooves are at the same elevation on all three blocks. If you have a pine tree, the bark on those trees is very thick so the screws on the blocks will only penetrate the bark. When the zipline is tightened, it will prevent the blocks from moving or shifting. 

Step 5 – Loop and Secure the Cable Around the First Tree

The loop around the first tree is very straight forward. Wrap the cable around the tree protection blocks and secure it with three or four cable clamps as shown in the picture. Make sure to use cable clamps that are made for 1/4″ cable. 

There are many different cable clamps out there, online or at the local store. It’s important to choose the right size for your application. For safety, use heavy-duty clamps. You don’t want to buy cheap clamps that could fail and cause injury. 

The first set of clamps I purchased was cheap and bad quality. After a few rides, the cable would sag because the clamps would slip. I tried to tighten the bolts but the tread failed and broke off with the bolt. So I went to the store and bought heavy-duty clamps for the same cable size. 

Step 6 – Pull the Zipline With a Cable Winch Puller

The second loop around the tree is a little bit more complex. First, insert the trolley onto the zipline before connecting to the second tree. Then take the hoist lift or winch puller and wrap the cable/chain around the tree and place the hook over the cable to lock itself. Next, cut a short cable section of about 5 feet and make a loop end on one end of the cable. Place the loop end into the hook of the winch puller. Stretch the zipline with your hands as much as you can and then connect this short piece to the zipline with cable clamps. Now use a winch puller to pull the zipline tight. See the diagram below for more details.

Step 7 – Make a Cable Sling and Wrap Around the Second Tree 

While the zipline is stretched with a winch puller, make a cable sling for the second tree attachment. A cable sling is a short section of cable that wraps around the tree with two loop ends. Wrap the sling around the protection blocks and connect these two loop ends to the turnbuckle. I’ve included links to Amazon of the parts you’ll need to make the loop ends and a turnbuckle. 

Have the turnbuckle unscrewed most of the way, which makes the turnbuckle long. Then feed the zipline cable thru the second end of the turnbuckle and make a loop end with thimble and cable clamps. Once you have the sling, turnbuckle, and zipline all connected then release the pressure from the winch puller. This will loosen the zipline slightly but now you have everything connected. See the diagram below. Use the turnbuckle to tighten the zipline to eliminate the sag. You’re done installing your DIY zipline. 

Step 8 – Build a Seat for Your DIY Zipline

There are dozens of seat configurations you could choose from. It varies from disc seat, swings, trolleys, harnesses, or even a spare tire. For this project, I used an old chained swing and added an overhead strut that holds the swing. 

Take a 1×1 metal tube steel and cut it to 22″ in length using a Sawzall with a blade for metal. Then insert and secure a 3/8″ eye bolt on both ends of the strut. These two eye bolts will hold the swing. Next, attach an eye bolt in the center of the tube steel but on the opposite side of the swing bolts. The center eye bolt will attach to the trolley. Use snap hooks to connect the swing chain to the eye bolts. 

Step 9 – Build a Frame for Tree Stand

Since the zipline starts high from the first tree and slopes down to the second tree, you need a ladder to get up to the seat. For kids’ safety, I wanted to build something permanent and sturdy. So I built a tree stand that they could stand on and get on the seat easily. With 20″ in diameter tree trunk, there are plenty of surfaces to attach the stand to.  

First, build a frame around the tree trunk. The platform of the stand is 40″ wide by 24″ deep. Take pressure treaded 2×4 and cut two pieces 40″ in length, two pieces to 20″ in length, and two pieces to 16″ in length. Attach the two 20″ pieces to the 40″ making the 40″x24″ frame. Then measure the diameter of your tree and mark that measurement on the backside of the frame. Attach the 16″ pieces to the backside of the frame on each side of the tree diameter measurement. 

Step 10 – Attach the Tree Stand to the Tree

Insert the frame around the tree trunk at the desired elevation and secure it to the tree with 4″ wood screws. Use a level to make sure the platform is leveled. Then cut and attach two diagonal boards that go from platform frame to the end of the 16″ pieces. 

Step 11 – Secure Diagonal Brace Under the Platform Frame

Having the tree stand attached to the tree with few 4” screws was not strong enough to support a person. So the two platform corners needed some kind of support to hold the weight.  

Cut two 2×4 blocks to 10″ in length and attach them to the bottom of the tree aligning with the outer corners of the platform. Then cut and attach the diagonal brace from the corner of the platform to the block at the bottom of the tree. Having the diagonal brace from both corners makes the platform firm and not sagging. 

Step 12 – Cover the Top of Platform with 2x4s

Now cut the 2x4s for the top of the platform and attach them to the frame. The boards on top will need to be cut at an angle to go around the tree trunk. Once the platform is complete, paint it with outdoor paint. 

My kids love painting, so they were excited to help with painting the stand. 

You’re done with the DIY zipline!