The previous homeowner often did not completely finish projects. Things look good until something breaks and we look closer at it. Our stairs look nice but we have discovered that none of the rails are fastened. Most of them have a cardboard shim on the bottom. I feel they should be glued at least- hot glue, carpenters glue? Someone will lean too heavily on the banister and several of the rails will fall out. Should I rearrange the rails to the best fit, shim some more(room for cardboard- not really enough room for wood), then glue?(what kind??) or do they need to be screwed in? Thanks for any help!!