One of the consequences of the ever increasing use of plastic for building products is the increased risk from vermin, which we are seeing in increasing numbers whilst treating rat and mice infestations.
In particular, plastic air bricks and plastic water pipes. This photo shows damage caused by mice, through which they gained entry to the cavity wall, and then to the attic of a new 4 story block of flats. From the attic they quickly found the kitchens and the residents had an infestation of mice.
This week, we had the same problem with rats, chewing a large hole in a similar air brick.
Then there are the plastic water pipes that are chewed by rodents in roof spaces, causing floods. The plumber at a pub with such a problem even replaced the plastic pipe with more plastic!
We say bring back copper pipes and traditional airbricks, though even these may need a wire mesh fitted.