Earthquake Safety Net

Hey all! This week I made a safety net for the storage space above a cabinet in our club room on campus at San Jose State University. Since storing stuff above head height is an earthquake hazard, we need to either prevent anything from falling down with a net, or not store anything above the cabinets.

Since that storage space is so valuable in our small club room, I opted for the net - but I strangely couldn't find a net for purchase in the size that I needed: 1x6ft. So, I'd probably need to buy a huge net and cut it down, but that seemed expensive and wasteful.

So, I decided to make my own net from rope and attach it above the cabinets with some wooden brackets.

The core of this project is pretty straightforward - some rope and a dowel to make the net, and some wood to make the brackets. I used 2x4 and plywood scraps and wood screws for the brackets.

I also used some 3D printed components to mount the net to the brackets. You could accomplish the same thing with some more rope and some carabiners, but hey - when you've got a 3D printer, every project is an excuse to use it.

As for tools, nothing here is required past a drill, a utility knife, and a saw of some kind. I used what I had on hand, including a coping saw, a chop saw, and a table saw, but if you use 2x4's without plywood, you can get away with a normal hand saw for all of the cutting.

Masking tape and sandpaper were also nice to have, but not required.

I used various wood screws to mount everything.

I originally bought just 50ft of rope, later doubling it to 100ft when I found it wasn't enough. Unfortunately, 100ft was just short as well, so I got 200ft of black paracord - that's why the color suddenly changes to black halfway through the project. Don't be like me! Get enough rope, it takes more than you think.

Here I'm just preparing the dowel for the net-making process. I started by sanding it smooth, using a drill to spin the dowel as I held the sandpaper. The dowel was too thick to fit in the drill chuck, so I wrapped the end in masking tape to give a place for the chuck to hold on to. The dowels come in 3ft pieces, so I had to cut mine down to an appropriate size.

I did find that both the rope had a bit of trouble staying in place on the dowel, so maybe I shouldn't have sanded it, but it ended up being okay in the end.

In this step, I attached cords of rope to the dowel to prepare for making the net. I used Klemheist knots, which I learned how to do from this resource. You could also use Prusik knots, which have the benefit of being symmetrical.

The trickiest part of this was figuring out what length to make each cord. Even though the net was only 6 feet long, it took me several attempts to cut cords long enough to actually make it the whole 6 feet. I ended up using 30 foot cords, which once halved were 15 feet. I wound up with a little less than 4 feet extra on each half, meaning I could've done it with cords around 22-25 feet long, but at that point I'd already restarted and wasn't looking to do it again.

Here's the most tedious part - tying what feels like a million square knots. At least, I'm about 80% sure they're square knots. I'm not a Boy Scout. This took me a few hours, but it was very straightforward. It's just tying the same knot over and over, where each row you alternate which strands get tied together. Here's a video of how it looks to start a new row with the opposite strands.

This is also where I had to restart because I didn't have enough rope the first time. I found it convenient to clamp the dowel to a chair, then simply move the chair back every time I ran out of room. This made it so I could keep all the cords organized while sitting comfortably at the table.

These wooden brackets were necessary for me because I'm not allowed to drill into the walls of the school building without filing paperwork and getting it approved (Boo!). But nobody can stop me from drilling into our own furniture, so this was a neat workaround.

I started with some 2x4's and scrap plywood, which I cut to the same width as the 2x4's with a table saw. Then, using a chop saw, I cut everything to size, including some braces cut at 45 degrees for rigidity. Using some differently sized wood screws (2", 3", and 1-1/4"), I screwed all the parts together and into the top of the cabinet.

A table saw and chop saw are obviously not necessary here, all of this could be done with just 2x4's and a hand saw. I do recommend a drill though.

Here I mounted the dowel to the right side bracket with some simple mounts I designed in Fusion and 3D printed. I used PETG for the durability, as PLA probably wouldn't hold up over time or in the event of an earthquake.

On an initial test, I draped the net over the left bracket, noticing significant drooping in the middle. I was worried about this as I was tying the square knots for the net, as everything tended to gather towards the middle. I think this happens with commercially made nets as well - I'm thinking of a volleyball net, where the borders of the net have a tape that can help maintain the width.

Fear not though, as I had a plan.

These are some guide ropes I attached to each bracket using spare rope from my initial failed attempt at making the net. They're tensioned and used to provide support along its length, preventing the drooping.

I used a few more 3D prints to attach these ropes. The right side and bottoms can be attached permanently, but the top left side can be removed to provide access to the stuff behind the net.

The entire net will slide along the lower guide, allowing access to the things stored behind the net.

Here, I secured the net to the guide ropes using spare black paracord from the net. I tied a simple overhand knot with a bight, including both the net and the guide in the loop. I did this on every other unit of the mesh on both the top and bottom.

After adding a few more 3D printed bits to the left bracket to make the left side of the net removable and cutting off the extra long ends, this project was finished!

This was my first time doing an extensive project with rope or paracord and I'm quite proud of how it turned out. Rope is an endlessly useful material and I'm glad that I did this, as I now feel more confident including rope and paracord in my projects.

If you make something like this, please let me know! I hope you give it a try.