In this Instructable I will be explaining the process I took to both design and construct a Wall-ball Wall for an elementary school. For those of you who do not know, Wall-ball is a playground game that is similar to handball, except for the fact that it is played in a court against a wall. This game was an integral part of my elementary school experience. I am currently working on achieving my Eagle Scout rank and so I approached a school looking for a potential project. They mentioned that they had wanted a wall-ball, and so I agreed to build them one.
The whole process was recorded via timelapse, so I you would like to see it happening, you can click the link above. For a literal explanation, you can read on.
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Step 1: The Design
The design for this wall went through many variations. In the end there were a few parameters that dictated how it could be constructed.
The location of the wall on the exposed blacktop near the San Francisco Bay meant that the design had to compensate for the possibility of high winds.
In order for the design to circumnavigate the necessity of a permit, it could not be build more than six feet high.
We also did not have the resources to dig massive pillar holes for the posts of the wall to sit in.
As a result we landed on a 6x16 foot wall design with two, small, sidewalls that give it most of its structural integrity. The side walls have posts sunk into the ground and are constructed using 4x4s and 2x4s. The main wall is build primarily out of 2x6 material and sits on blocks, both to allow water to flow and to allow for leveling adjustment, since the ground was presumably not flat.
The wall is covered with 3/4" MDO plywood and protected with two coats of outdoor paint and a capping 2x8 beam on the top.
I spent time with a structural engineer doing all the math to make sure that the wall would stand up to the elements, and to the stresses of getting banged on and ran into by small children.
Step 2: Preparation
A BIG part of this project for me was planning and preparation, so I feel like I have to give it another step.
I wanted to complete this project in one weekend, which would require really effective coordination of volunteers and a clear vision of all the steps before starting. I spent time planning work-flow and designating parallel tasks. I drew up diagrams, visited the site to survey and mark out drilling spots, and contacted a lot of potential volunteers. I ordered plywood, arranged for it to be delivered, purchased and transported all the materials, and packed up a lot of tools.
We also rented three tools from Home Depot: a two-man auger, a small jackhammer, and an electric cement mixer. We used a friend's truck to pick these up and transport them.
Finally after weeks of preparation we were finally ready to start.
Step 3: Groundwork
The groundwork was pretty simple. The holes that we marked in the asphalt were spaced on the corners of a 6x16 foot rectangle. We then drew 12" diameter circles around the centers. We used the jackhammer to break up the asphalt so that the 10" diameter auger bit could fit in the hole. The asphalt was not terribly thick or strong, so it came up easily.
Augering is hard work, but you basically have to hold it really firmly, give it plenty of throttle, and use your body weight to get it to bite into the ground. After grinding for a bit we would eventually hit a clay-like layer in each hole, and the drill would just sink right in. We used a post hole digger to clean out the holes and each ended up being about 3 feet deep.
Step 4: Setting the Posts
Setting the posts presented an interesting challenge. These posts needed to be perfected vertical and precisely spaced apart from each other. Our method for doing this was to screw each pair of 6', 4x4" posts to a piece of plywood so that they were parallel to each other and spaced 6 feet apart on the outsides. We then build little stands out of extra 2x4 and plywood to screw to each post to hold them at the right height. We checked level in all dimensions and adjusted the stands to hold the posts perfectly. Then we did the same for the second pair of posts and additionally measured to make sure that the pairs were correctly spaced away from each other.
Meanwhile we mixed up concrete in the mixer and shoveled it into the holes. We used shovels and trowels to set the concrete and smooth it out on top. We shaped each concrete pillar to be a bit domed so that water would not pool up around the wooden post.
This step was done by about 11:00 the first day. We used fence-post mix, so the pours were mostly dried by the end of lunch.
Step 5: Spacers and the Main Wall
The main wall construction was very simple; a grid of 2x6 and 4x6 beams framing out a 6x16 foot wall. All studs were placed 16" apart on center, and all connections were made with pre-drilled 3" screws. I put a seperate team on the main wall construction, so it was finished before lunch.
After the posts were set we started to put down the blocks and spacers to get the wall level and off the ground. We started by nailing 2x6 blocks to the ground using a Ramset Nailer. We then strung a level mason line above the blocks and cut custom shims from 4x6 and 4x4 to meet that line. All these shims were attached using screws to the nailed blocks.
When this was all ready, we made sure the wall was square and screwed plywood to it for sheer. We gathered a large group of people, carried the wall over, and set it on the blocks. We positioned it with a sledgehammer and used 2x4's to hold it vertical to the posts. Miraculously, the wall was perfectly level.
Step 6: Side Walls
Building the side walls was the most time consuming step, mainly because it required a lot of custom cutting and measuring, and because I ended up doing most of the work on my own.
We first cut a 35 degree angle off a 2x4 and screwed it vertically to the main 4x6 beam. We cut spacers and nailed them to the ground as we had done for the main wall. Then, after measuring the distance from the wall to the post, we put in a horizontal 2x4 on top of the spacers.
Then we took a 4x4 beam with an angle cut on it, and lined it up above the vertical 2x4 to mark where it would intersect the 4x4 post. with this done we cut off the 4x4 post with a circular saw and made the compound cut necessary on the angled 4x4 so that it would sit on top of it. We attached these beams with 3 inch toenailed screws.
We cut two 2x4's with 35 degree angles to act as studs, these were toenailed in.
This process was repeated three more times to build all four side walls.
Step 7: Plywood and Weather Proofing
The wall was designed to have studs to attach 4x8 sheets of plywood to, and we ordered 12 sheets of 3/4" MDO plywood for the job. This plywood has a special laminate layer that makes it very flat and especially good for outdoor use. During our first day, the plywood had all gotten a first coat of weatherproof, matte paint.
Now that the wall was up and framed we screwed a capping beam onto the top of the wall. This was supposed to be a 2x8 board, but there wasn't one available when we went shopping, so we bought a 2x10 and ripped it down to width. With this in place we could measure from the beam to the ground in 4 foot increments and cut our 8 foot tall plywood down to fit the curve of the ground. Each piece was cut off with a circular saw and screwed to the studs using many, many, 1 5/8" screws.
For the side walls we lined plywood up against the sections and marked the final shape. We cut them out with the saw and attached them with more screws.
In the end we only used about 10 1/2 sheets of plywood.
We also decided to add capping boards on the edges of the side walls so that water couldn't get into the plywood. This involved a couple more 2x6 boards and some angled cuts.
Step 8: Paint, Paint, and Paint
This project went very smoothly, and so we had time to do a lot of painting. We started off by giving the whole wall a second coat of the matte outdoor paint. We ended up using every drop of our one gallon.
We then power washed the area and marked out lines to paint borders on the asphalt. The borders formed a 16 foot square around each side of the wall. We also painted black asphalt paint over the existing color on the blacktop. This not only helped with the color scheme, but also had the effect of defining the area as a unit, not just a wall with some lines around it.
The designs on each side of the wall are purely abstract. My sister and I came up with two fun designs that could be painted in three steps with three shades of blue. We made diagrams in Photoshop to show each step and it's placement on the wall. Then using masking tape and estimation we marked out each step and painted.
After touching up all the drips and spots, the wall was complete :)
Step 9: Final Thoughts
This project went better than I ever expected it might. The plan and design worked great and we constructed the whole wall with almost no slip-ups in one weekend.
As far as the design goes I am very pleased with it and wouldn't make any changes, except to maybe get a permit next time so we can build an 8 foot wall.
If you feel like attempting this project on your own, know that it takes a lot of work and coordination and money, but it will be satisfying and make a lot of kids happy. Feel free to reach out to me with questions you might have. Unless you are planning an Eagle Project, then do your own work ;)