Outdoor Bouldering Wall - Which grade plywood?

Before people get angry, I've read a lot of the literature online about different types of plywood for outdoor walls, and there are several different responses. I haven't been able to find people comparing the different grades anywhere (other than thickness).

I'm going with 3/4" thickness, so that's not the question. Many people recommend ACX, however I live in northern Indiana and we get a lot of nasty weather (lake effect snow, a lot of rain, etc.). I've still read that sealed/painted ACX would work, but I feel that it might be inadequate. Has anyone used ACX in these conditions with success?

I'm now considering either pressure treated ACX, or Marine grade. Marine grade is significantly more expensive ($70 a sheet, not including sealing materials), but is suppose to be much better in damp conditions. Any thoughts? I've read a lot of negative things about pressure treated plywood in general.

I'm also open to other building materials, but I can't spend a fortune on something like trex.

Thanks for the help!

I live in Ohio. I had an outdoor 16' x 16' climbing in my side yard (anchored to the house but not next to it - so no protection offered by the house). I used regular 3/4" cdx plywood and kept it painted (especially the edges). I had it up for around 12-13 years and repainted it maybe twice. I had to replace one sheet in that time. It was half overhanging - I did put a "roof" on it that covered all the top edges - and painted that yearly. All in all, it took very little effort or expense for upkeep. Pressure treated would no doubt be best but keeping the edges protected and everything painted seemed to work very well for me. I did use pressure treated and steel for all the framework.

Yea treated and paint. Just beware my holds would stick to the paint when I went to change them. Instead of using your hands or fingers to pry them off get a small pry bar (sometimes the paint would come off). And what ever you do DONT MIX SAND IN THE PAINT TO GRT FRICTION I scraped all my paint off and had to redo it. And all you get is road rash knuckles when you pop off a hold.

Contractor emeritus. The only dif acx vs cdx is the face grade of the ply. Same core, same laminate, same shear strength, same glue. Just prettier. If you are concerned about strength and longevity, count the # of laminates in the ply. There is everything from 5 ply to 13 ply. The more plies, although the aggregate thickness is the same, the stronger.
And i have two exterior woodies, NorCal mountains. Best if you can keep as much water from infiltrating as possible...IE tarps, roof, etc. But the x in cdx, acx, etc, is for Exterior, as in outside. Should be fine.
Treated ply is suspect, and splinters from said such are really toxic, and infect badly. My advice, stay away!
I have 100's of holds for sale, btw. Pm if interested.

My climbing wall has been sitting 6 years outside in Colorado. Just make sure that water/snow can't sit anywhere on your wall as that is where all of my damage came from.

In the below link there are many photos of the backside/frame of my wall. Prior to covering the frame with 4x8 siding the snow/rain would sit in the frame and melt. In a matter of <2 years the wall was heavily damaged from the weather. I installed the siding material and in 4 years have had minimal additional damage.

Since most walls are overhanging it is really just the backside that you need to protect, but all depends on your design. Exposed wood that is not getting directly rained on should not be greatly affected.

andylibrande.com/homeclimbi…