yes you are correct- definitely bumblebees.
They could be one of two species either Buff-tailed (Bombus terrestris) or White-tailed bumblebees (Bombus lucorum)
These are sometimes difficult to tell apart from photos as both of these species have two yellow stripes and a pale tail.
In the case of Buff-tailed bbs, the yellow colour is very dark almost golden brown and the tail can be white to buff-coloured. They are slightly bigger than the White-tailed bbs, whose yellow colour is a very bright lemon yellow and they have a very bright white tail.
You can learn about the common bumblebees here http://bumblebeeconservation.org/about-bees/identification/common-bumblebees/
Bumblebees can’t do any damage to buildings. They can only use pre-existing holes. But they could potentially cause a blockage I suppose, so that is something to think about. The nests don’t last for very long, just a few months over the summer. Then all the remaining colony will die off. So you do any necessary repairs then.
Enjoy them, they are a pleasure to watch going about their busy lives