I'm building a cockpit sole for a small powerboat and I'm torn between end-grain balsa and PVC foam. It's a high-traffic area with people standing and dropping gear on it, so I want the stiffest, most dent-resistant option but I'm a bit nervous about water getting in over the years.
For a walked-on sole the trade-off is real and worth thinking through. End-grain balsa is stiffer and gives excellent compression strength under point loads, so it resists denting from dropped gear and takes hardware bolt-up well, which suits a hard-working sole. Its weakness is water, because if the skin is breached and water reaches the balsa it can wick along the grain and rot, so every fastener penetration must be properly sealed and overbored. Closed-cell PVC foam will not rot and shrugs off water intrusion, but a soft grade can feel springy underfoot, so you would size up the density for a sole. A sensible path is balsa for stiffness with disciplined sealing, or a higher-density foam if long-term water resistance matters most. Both sit in the foam and balsa cores range, and if you want a hand matching density to the load, get in touch.
Ask the Allbase team and we'll add the answer here for everyone.