no you are the one coming here for help. take the time to formulate a proper question and say thank you.
this is a basic installation and it firghtens me to the core that an installer is having to ask this question, it tells me that you are not qualified to do the job. why does this bother me? because our industry has been overrun by people who do not know what they are doing.
and even with all of the advice you have been given you are still installing these
signs in an inproper way.
myself i sleep much better at night with mechanical fasteners knowing that my
signs will not fall off and at the very least i will not have an unhappy customer because some teenager yanked a
sign off the wall, or worse that it fell and hurt someone or that it failed because someone before you did not paint the building correctly (as the only bond you have is between the paint (stucco uneven surface at that and the back of your
sign) and you are using the worst adhesive that you could for this project. i can accept not using mechanical fasteners on an 11X17
sign if it was not overhead, and the customer insisted that it was installed without fasteners and i would have him
sign away all of his rights to complain about anything but it would definitely not be my first choice in a parking structure on stucco with over 20 yrs of experience and yet to experience an installation failure i will stick to my technique.
my biggest pet peeve has got to be when posters come back and tell you the rest of the story. take the time to post the details of your project if you want an answer instead of making people pry information out of you or worse when you dont get the answers you want add more info hoping that people tell you what you want to hear...wild. the only thing you should have said was 'thank you'