Not much. But if you want to take it the next level, it is an easy computation that requires some basic math. We use 30-pound HDU Sign Foam as our substrate material. 30-pound density means that it weighs 30 pound per cubic foot, which is 12″ x 12″ x 12″. So, all we have to do is compute how many cubic feet of material is in your sign. As a simple example; a sign that measures 12″ x 12″ x 1″ thick would be 1/12 of a cubic foot. So would have a basic weight of 30 pounds divided by 12 which is 2.5 pounds. Then add about 1/2 pound for the metal coating and an allowance for mounting hardware and the weight computes to 3 pounds. If the plaque is 2 inches thick, the basic weight would double, and with the same additions, would weight about 5 1/2 pounds.
Most signs from Atlas will not require structural alterations to your building.