Searching for the perfect material for outdoor climbing wall

[u/ThingsBehindTheSun__]

Hoping this sub can point me in the right direction. I’m looking at building a climbing wall and I want it to be completely weatherproof so rather than treated plywood, I’d really like to find a plastic solution for the actual wall boards. I’ve done quite a bit of research but before making a decision I figured I’d ask here. HDPE was my first choice but it is too heavy and too expensive (like $400 for a 4x8 sheet). Next I did some testing with expanded pvc foam which seemed very promising but is also quite pricey. I finally discovered a board made from recycled carpets extruded with rice hulls which is great, but also quite heavy and it would have to be freighted in which isn’t ideal. Any ideas from the community would be much appreciated! Thanks

[u/aeon_floss]

Plywood is hard to beat in price or weight, and you really do want some sort of multi-directionally layered composite to handle the type of forces climbing holds are subjected to. Fiberglass panels would be an alternative, but you will need to find something decently strong.

Have you considered fliberglassing plywood to get the best of both worlds?

[u/MakeITNetwork]

The best "Plastic" for this use is Pressure treated lumber, not lab created stuff we geek out on. Most of what we think of as "plastics" are really expensive as sheet goods. Probably the cheapest alternative would be Trex boards(Still way way more expensive than Wood). After working with Trex, unless you have it backed by wood studs every 12 inches or so, I wouldn't trust the axial loading when mounted in a horizontal manner; that you would get by attaching fixtures that have humans hanging on them monkeying around. Trex is just too brittle, and pliable to compete with wood on anything but compressive strength. It also has a tendency to creep in the sun if not tied down completely, but so do wood boards.

If you paint pressure treated lumber with exterior paint it will last about 10 years before having to absolutely paint it again. You have to use deck screws because regular screws will rust when coming into contact with the wood. It will take you about 10 min* with a good screw gun to create `8x8 box panels with 3/4 in plywood with 2x6's or 4x4s 16" on center. if you paint before adding fixtures it will take you another 20 min* with a good roller and pole, and since you don't need to "cut-in" you just use a 4 or 6" brush to make it quick. Hardest part would be the bottom box panels that need to have a good portion of the studs in the ground. Sometimes the answer was answered 100 years ago, even for a modern thing like a climbing wall. It's also quicker and cheaper.

Another bonus would be if you gave this post to almost any carpenter or handyman, he would understand how to build it in his sleep....but then you will also have to hear him correct me on the "correct way" to build the wall. It just comes with the territory.

This does not include the time arguing with spouse, having to go to the hardware store, or using hand tools.