My son has SO much energy that when I saw a photo of a kids room with a climbing wall and the mattress on the floor to land on, I decided then - Yes. The project took some time to complete but was well worth the effort. Here are my tips before you spend money and instructions once you have all the supplies.
One Wall (double this order if you want to make 2 panels):
1 - 8ft x 4ft Maple 3/4 inch or 1/2 inch plywood. (Maple wood is smooth, easy to sand and has a nice modern aesthetic and texture with clear finish). $45.00
3 - 8ft long 2x4's (make sure they are not warped when you buy them and ask the store to cut them to 7ft if possible) $35.00
Hardware Option 1: Round Base T-Nuts that you can hammer in.
Hardware Option 2: Round Base Heavy duty 3/8" Zinc plated T-nuts -(RECOMMENDED)
Hardware Option 3: (No Photo) Screw climbing holds directly into wall mounted plywood.
While option 1 is a little less expensive and is faster to install, I don't suggest it. The teeth in the option 1 hardware can and likely will back out when you start to change the wall holds around. You can not repair this once the board is secured against the wall without removing it completely from the bedroom wall. Last, if too many pieces of hardware pop out, the hardware can not safely secure a climb hold to it rendering it unsafe. My son was really sad when he realized he had a few "dead" spots on his wall where hardware for holds will not go.
Option 2 hardware is the way to go. The three screws in back ensure the hardware will not pop out when running the hand hold screws from the front. Expect tired arms as there are 66 holes per sheet of 8ft x 4ft ,3/4in maple plywood (more or less depending on spacing). Each hole requires 3 screws to bolt in each piece of hardware so be prepared to screw in 198 1 inch screws per plywood sheet. A fun audiobook or music makes the project go faster.
Option 3 Hardware is pretty easy. No predrilling or placement of the above hardware. You only need to sand and finish the wall board, secure it to the wall. The climbing holds are attached by a screw to the front of the board one the wall is in place. The downside, you can not change the holds without drilling into the wood causing splinters and holes and two, kids can not change the path up and down the wall over to design new paths. Doing the extra steps of drilling and adding the hardware makes the wall useable for all levels and ages of climbers for many years.
Preparing the plywood
Measuring / Hold Hole Spacing
Measure and mark out the spots to drill the holes for hardware. The spacing should be bigger for an adults wall and closer together for children. For my sons wall, I opted to space each hole by 7 inches. Once all drill marks are set, get a powerful hand drill and begin.
If the wood splinters badly with your drill bit, you may want to buy a specialized bit for drilling wood that has a pilot point tip (see photo of the first bit I used on right vs. the 2nd on the left. Be sure to drill straight so the hardware seats flat. I was able to use this board by making the damaged side the back which faced the bedroom wall and changing to a new drill bit.
Sanding and finishing - Repeat 3x's
Round 1 - Sand down what will be the front side of the wall with medium grit sand paper for the first sanding. Wipe down the dust off the board with a damp towel and then brush on first layer of Polycrylic Finish making sure to avoid drips. (We used q-tips to clean out holes that held and bled down finish). Apply even coat and let dry 1-2 hours.
Round 2 - Lightly sand with fine sandpaper the entire face of the wall board. Wipe down again with damp cloth. Apply second coat of Polycrylic Finish.
Round 3 - Repeat round 2.
I took the time to sand the edges and corners of the plywood and added lots of finish to the sides in case little hands grabbed the outside edges, they would not get splinters.
Hardware installation onto Plywood
Place climbing wall board (finished side down!) and begin putting in the hardware into each of the holes. Get your power drill and some good music going and drill away until all the holes are filled and secured with hardware. The plywood will be heavy once it is finished with all the hardware installed - get help moving it to the space it will be vertically mounted.
The 2x4's should be cut to 7"ft. Mark the location where you will pre drill holes for the screws. First hole should start 5 inces from the top and then every 12 inches to the end. I found it useful to have the screws started in each hole in the 2x4's. Especially since I was installing without a help.
First use the stud finder to locate the studs in the wall (usually they are every 13.5 inches apart depending on your construction). Mark the center of where the stud is both close to the ceiling and close to the floor, this will allow you to place and center the 2x4 over the stud behind the drywall. Use the level to make sure you keep the center line over the studs.
Once the 2x4's are mounted on the wall and in place, measure the distance across and then measure and map the line on the front of the plywood wall. Next, drill holes to sink the screws and secure the plywood climbing wall into place down. To make it super safe, sink a screw every 12 inches vertically making sure you are sinking the screws into the 2x4's. If you need to have the back of the wall hardware make contact with the 2x4's, it is okay, the hardware for the climbing holds will still function with wood behind them. Ideally, the space behind the hardware is open.
Add Climb Holds and enjoy
Now the fun begins. Get your holds out and the bolts to begin placing them along your new climbing wall!