What is the recommended installation position for the first course of shingles?

The recommended installation position for the first course of shingles is along the eaves. Installing the first course here provides a solid and level starting point for the roof covering. Positioning shingles along the eaves ensures proper water drainage off the roof and helps to protect the underlying materials from moisture damage. Additionally, this orientation allows for proper alignment with the subsequent courses of shingles, ensuring a consistent and aesthetically pleasing appearance.

Choosing to center shingles on the roof might lead to incorrect alignment and potential water pooling issues, while placing them on top of metal flashing could hinder the flashing's effectiveness in directing water away from potential leaks. Installing shingles under the drip edge would defeat the purpose of the drip edge itself, which is to channel water off the roof and away from the structure. Therefore, aligning the first course along the eaves is critical for both functionality and longevity of the roofing system.