After reading others tout the virtues of this material for numerous uses I decided to give it a try.
I have nucs that I made from some 3/4" band sawed pine. The boxes glued and stapled together nice and square but the lids warped a bit since I didn't fully dry the wood (only two and a half months stickered in the garage). The resulting gaps causes water to leak into the nuc.
Our local lumber yard has tons of this Advantech material in various thicknesses. 1/2", 3/4", 7/8", 1" and 1 1/8". Lumber guy said it is what almost every contractor uses for subflooring since we get so much rain before they can get a roof on. It has a waxy feel to it, cuts like a dream. I bought one sheet of 3/4" for $24.98 and made replacement lids for all of my nucs. Just because I had it laying around and like the look of a white top on my green nucs I threw a coat of exterior latex stain on them. They fit the nucs snug as can be and are perfectly flat and true. Once I get a case of mason jars I will drill a hole for a hive top feeder in each.
I also put some scrap pieces outside to see how they take the weather without any stain at all. Since it has a "50 year warranty" I doubt I see will see much in the way of degradation in the next year or two.
I liked working with this material so much I am going to build some top covers for my normal hives next! Pics to follow...