If your roof meets engineering standards (meaning it was built to code and inspected and approved by the local building department), it should be strong enough to support a solar array. While a complete solar array is quite heavy, this weight is distributed evenly across a large area and the overall pressure it exerts is low– about 2 pounds per square foot. This pressure is easily supported by a roof.
Most of our solar installations in Florida are built to the strict Miami-Dade codes and have been designed to withstand hurricane-force winds of 175 mph. In addition, the racking used to secure the solar panels to the roof often effectively functions as cross-bracing to the roof and increases its structural integrity.