My daughter and her husband are having a house built. The house is mostly brick and the builder puts aluminum siding over all the outside trim. He doesn't paint any of the trim before he installs the aluminum trim and says it doesn't need it. I worry about moisture forming behind the siding and the bare wood absorbing the moisture and rotting. Mostly on the side that has the evening sun and then cools quickly once the sun goes down. Does anyone know if this procedure is correct or should the trim be painted first?