We have supplied and installed applied lettering in various museums, galleries, corporate campuses and other interior locations for many years using the proper products for the job.
About a year or so ago we had two instances of the lettering slowly curling off of the wall. Although we haven’t definitively identified it, we believe there are ingredients in some of today’s paints the make them easy to wash and repel stains, but unfortunately it also affects the adhesion of our lettering.
Now we test all painted surfaces for proper adhesion before lettering. Photo below is from a historic building with new paint. We applied these letters to test adhesion and no problems!