This little hotel is made of recycled material. The cans are emptied , rinsed, spraypainted and filled with bamboo or reed cut to length with a metal saw. No need to plug the back end, the bees know how to do it. The roof is made out of recycled plastic shingles which are used for protecting cables burried in the ground. The cans and roof are attached to the backboard with screws and construction glue.
This little project is also fun to watch when action is going on. A few days after I hung the construction in my garden, the first bees moved in. The advantage of this system is that used tubes can easily be replaced.