What is a potential drawback of using aluminum coatings?

The potential drawback of using aluminum coatings lies in the tendency of these materials to cause surface movement. Aluminum coatings are applied as a reflective layer to protect underlying roofing materials from UV degradation and to help manage heat. However, due to the thermal expansion and contraction characteristics of aluminum, these coatings can lead to surface movement as temperatures change. This movement can result in cracking or other forms of degradation over time, compromising the integrity and effectiveness of the roofing system.

While aluminum coatings do offer benefits such as waterproofing and UV protection, they are not without their challenges. It's important to consider how their properties affect the roofing material beneath and the overall durability of the roof.