My son wanted me to build a suspension bridge to our summer cottage. I liked the thought and decided first to build some platforms. Building a tree house is a topic with a lot of articles on the web. I’m trying to focus on a design that works in relatively medium sized trees and considers the well being of the tree itself.
I’ve built a rope bridge before. It was on a scout camp with nothing to do and ample amounts of hemp rope and wooden planks. It was fun and surprisingly easy. And as an added bonus, I got to hang around in an harness(?!)
However, this time I was planning to use wire and a suspension cable to actually make a proper suspension bridge. But before I could get there, I needed to make the platforms, the tree house itself where the bridge would lead.
I did some research on how to attach a treehouse to the tree. The main methods I found were:
- Bolt the support beams directly to the tree trunk (usually using these special anchors)
- Bolt anchors and suspend the platform from wires
- Don’t attach the platform to the tree, rather use beams to support it from the ground.
My issue with all of these were either a) My trees weren’t big enough to survive the massive anchors or b) creating self standing platforms around trees weren’t the “real deal” in my opinion. So I started looking at how this adventure parks that allow you to climb these really high platforms attach them to the trees.
I found out, that using these shims that are spaced equally apart allow for the tree to continue to provide it’s roots with recently photosynthesized sugar through the gaps. Heavy beams are then compressed using threaded rods against the shims. As the tree grows, the installation becomes even sturdier. Note: the shims need to be impregnated wood to stay in place and not rot away.
So I did some sketches to help me buy the right material.
Being a cheapskate, I was planning to mill my own lumber, but decided I’m not proficient enough yet.
I started the build by attaching the impregnated 2″ x 6″ with two threaded rods on both sides of the tree. Then another set of 2″ x 4″ perpendicularly to the previous set. I had bought nylock bolts, and boy I have to tell you that threading them the whole way was quite a chore.
The first two beams were a bit flimsy and I wasn’t sure would the setup hold, but as soon as I attached the second pair of beams, it the whole setup sturdier in an unbelievable way. I was literally jumping on the beams from joy! My plan worked.
Next, I built two of these modules pictured above. It was just a simple case of screwing 2″ x 4″‘s together and making some mitered cuts. I used stainless steel screws but the wood was just plain pine wood without any treatment. I’m not planning to make this a too permanent solution.
Placing the modules on the beams and securing them in place with screws, I then measured and cut the two cross beams that’ll be the sides of the hexagon. I carved slots to the main two-by-fours and mitered the ends of the planks. With a single screw to hold the end plank in place, the supports for the decking were in place.
I then started the decking. Simply screwing in planks on the support, making cuts to allow for the tree to grow in the middle. I did the final cuts after I had attached the planks, so that the finished platform would be neater.
I was then planning to which tree I should build the second platform to house the bridge. The first platform was built on a slope, so that I wouldn’t have to build any ladders, the natural inclination would allow the bridge to span to sufficient heights.
I started building the second platform, but didn’t get very far when I realized, that the 6m in between the platforms would prove quite a challenge for my bridge. Three meters would probably just as cool for my kids and significantly easier to make.
So I scouted our yard for a better location for me to be building a tree house.
Disassembly and reassembly
I’m very happy about the fact that I spent some time designing the platforms, as dismantling it was a breeze. Reassembly was as well! However, since the decking was made for a certain width of a tree, it didn’t look that good anymore. I had to scrap some of the pieces and make some new decking planks.
I decided to forgo my “no-ladders” policy, and built the second platform on top of the first where the bridge would then start. This would allow me to make a bridge of approximately 3 meters to another tree.
End of part 1
The summer ended so quickly. I managed to plan and install the two platforms. I still need to build a third and the suspension bridge is still to be planned. The kids love the lower platform already, I haven’t allowed the to climb to the top before I get some railings going on.