On 02/08/2020 10:37:25, Roger Hayter wrote:
wrote:

On Saturday, 1 August 2020 12:24:11 UTC+1, Roger Hayter wrote:
snip
NT

As a matter of interest, what can you specifiy nowadays if you want
waterproof plywood?

https://www.contractflooringjournal....d-there-is-no-
such-thing-as-wbp/


NT

Thanks, that's helpful. But doesn't help with the elusive marine
plywood which is allowed to be wet! Perhaps it never existed.

I'm not sure if it did. As I have said earlier the closest you can get
in buffalo boards that I have seen weather outside for 30+ years. They
were still sound and were showing their age more from a cosmetic point
of view. I have also seen marine ply last 30 years as a narrowboat
floor. One side would have been exposed to a wet bilge. Some areas were
becoming soggy.

In terms of specs there are some BS and ISO number as indicated by
various links in this thread.

But for total immersion I might use plastics like:

https://www.kedel.co.uk/mixed-plasti...50-x-50mm.html

Not cheap.

OSB of the right grade is used in houses where the panel is subject to
moisture, but again not immersion.