Prefabricated garage roof covering needed? Is weather protection sufficient?

We purchased a single prefabricated garage from Dahmit through the general contractor. My question: Does a layer of gravel need to be applied to the garage roof (for protection against, for example, UV radiation), or is the garage roof already adequately protected against weather influences? In case a protective layer, such as gravel, is necessary, can it be applied directly, or must a foil first be installed on the roof? What are the opinions and experiences? Thank you

No, it is not necessary.

Leave it as is. Don’t make things worse by trying to improve them.