What is the method used to raise the butts of tiles in the starter course meant to allow for?

The method used to raise the butts of tiles in the starter course is essential for ensuring proper roof drainage. When tiles are installed in a roof system, it is crucial to allow water to run off efficiently to prevent pooling, which can lead to leaks and damage over time. By elevating the butts of the tiles, the design facilitates a more effective drainage slope, directing water away from the roof and down towards the eaves. This aspect not only enhances the longevity of the roof but also maintains its functionality in various weather conditions, particularly during heavy rains.

In contrast, while structural integrity, heat expansion, and aesthetic appeal are important considerations in roofing systems, they do not primarily address the core issue of effective water drainage, which is critical to the overall performance and durability of the roof.