After six years out in the weather, I have retired my Durabak test panel.
As a recap, the test panel was a piece of bare 9mm marine grade Okoume plywood. I only coated the top. It was then positioned horizontally in full sun outside. Over the last 6 years it has seen low 20’s – low 100’s, 220+ inches of Oregon rain, snow for weeks at a time, many freeze-thaw cycles and baked in the sun.
I’m happy to report the Durabak has held up fine with only minor fading. Because the entire panel was not coated, some rot has developed, but not under the Durabak. You can poke at the edges and get no sign of lifting.
I’m assuming with a good scrubbing and a coat of 303 Protectant the panel would easily be good for many more years.
As discussed before, aging of your compact camping trailer’s finished if stored indoors is somewhat like dog years. One year of full weather exposure on a finish, is roughly equal to the exposure a trailer stored indoors would see in 5-7 years.
So conservatively, a Durabak coated compact plywood camping trailer stored indoors would have a finish life expectancy of 25+ years.
Stay tuned for information on a new House Paint finish test panel.