I have been researching composite/PVC deck boards and the issue of how many sides are capped seems to not get enough attention, at least in the technical sense.
What should I think about with regard to the choice between 3 and 4-sided capping? All I have found is talk of looking up at it from below. In my situation, while I am planning a 2nd story deck, it will have a between-the-joists drainage system, so you will not see the underside of the boards. Does the fact of the drainage system mean I should favor 4-sided caps because of the moisture? Or are there other factors to consider?