Re: Beeproof top bar hive screened bottom, not so much
Bees will chew through plastic, given the time and if they want to.
In shallow hives (as in TB) they do want to expand down and will try to chew down.
In a deep hive with enough vertical span, plastic should be safe - not much drive to chew down.
Storm door window metal mesh works just as fine (and is really easy to collect by the road sides and at recycling - FREE).
Former "smoker boy". Classic, square 12 frame Dadants >> Long hive/Short frame/chemical-free experimentations.