Every year the stem discs in the bee hotel deteriorate a bit more. Cracks run through them and make the nesting holes less usefull for the bees that clearly don’t like it and ignore them after inspection.
I still had an unused fresh stem, a bunch of smaller stems and some waste wood, so a good moment for some maintenance and expansion.

First the frame was attached to the wall and then filled up layer by layer. As soon as the first block of wood was put into the frame the bees, Red mason bee, started immediately to nest.