Tweeters,
Pileated Woodpeckers do not import nesting material into their nest cavity. A pileated woodpecker working over a building is either in search of food and is successfully finding it, or out to make a bunch of racket.
At this time of year, Pileateds are on eggs. The adults do shift work for incubation, and often the bird that is not on egg duty will drum loudly (to let the mate know its whereabouts?). I had one male for several years that would use a swallow box as a drum that could be heard for quite a distance.
-Jamie