My friend has a koala camper with adzel outer wall construction. Looks nice and holds up well. its supposed to be immune to water absorption and mold. from the net:
ยท 50% lighter than wood
ยท Offers 3x the insulation value of wood
ยท Odorless, Formaldehyde free
ยท Sound and energy absorbing
ยท Impact and puncture resistant to help prevent damage
ยท Impervious to water: Unlike wood it will not rot, mold, or delaminate sidewalls causing costly damage
2017 Grand Design Reflection 303RLS towed by a 2016 GMC 2500HD gas with Andersen hitch and B&W turnover ball mount.