A bee swarm in roof space is one of the most inconvenient bee situations to deal with. If there's a space in a roof or wall, with a hole big enough to allow a bee to enter, a swarm can colonize it.
If you ever see a procession of bees entering and leaving a place in your house, you might want to try to block up that hole. If you push a wadded up plastic bag or a piece of old cushion foam into the hole, the bee scouts will give up and find somewhere else.
If a colony has actually moved in, like the picture here, they will start to build combs, store pollen and nectar, and lay eggs. Once they have reached this stage, they are very difficult to discourage.
This swarm found a space inside the edge of a roof of a house which was under renovation. The builders tried to block up the entrance, but the bees just found another.
In the end we had to cut away a board and physically remove the bees and take them away so that work could continue.
