Carpenter bees nest in dead or live wood and bamboo. When they nest in support structures of buildings this can be a problem but this is rare. During mating season (summer) they can chase each other and bump into windows and people and this act can be mistaken as aggression. But they are docile bees and the female bee will only sting if provoked. The male bee cannot sting.
Generally these bees nest in already rotting wood but people often mistake the rotting to be caused by the bees. If you suspect you have carpenter bees and have concerns about your building, please phone Beegone® as they are qualified for removal of bees and for minor works on listed buildings.