When, several years ago, I complained to my builder about using masonry nails to fix a bio-degradable, grill to the outside wall of may house ( to close off the external vent hole for the internal extractor fan in the kitchen) all I got for my trouble was criticism for being "too fussy".
10 years on and I have been vindicated: the grill has indeed (virtually) disintegrated - as I predicted it would, at the time - and because it was fitted(???) , i.e. fixed, to the wall using 'Obo' (masonry) nails it meant that the grill was not serviceable, that is, I had no easy means of replacing the grill ahead of it actually falling apart. Also, until now, after reading through several of the DIY Doctor' s forum contributions, I had little or no idea how I might replace the grill without having: 1) to wrench the grill off the nails and: 2) how to remove the nails without damaging the, relatively new, painted, pebble-dash render with little hope of getting a good match on a very exposed, highly visible, wall of the house.
In my case I think wrenching is the only way forward - hoping what remains of the grill is soft enough (at the corners where the nails pass through) to not damage the render, and then, attack the nails with a grinder careful not to, again, damage the painted rendering. At the end of the day I firmly believe I have experienced an example of "cowboy building" by a very high profile developer where I live. I understand plastics quite well - having studied the subject at a technical college as an adult student - so I was confident my prediction was sound - as it proved to be. To fit products not 'fit for purpose' is both unprofessional and bad practice; compounded further by the use of totally inappropriate fixings, which should have been at least stainless steel screws to give the householder at least the opportunity of maintaining the fitting [b]before[/b] it falls apart, as mine did.