How should joints in alternating courses of shingles be arranged?

Joints in alternating courses of shingles should be arranged in a staggered manner. This practice is crucial for effective water drainage and protection against leaks. Staggering the joints enhances the shingles' ability to shed water, as it prevents water from flowing directly down the seams. When the joints are offset, it creates an interlocking effect that minimizes the potential for water penetration, ensuring a more robust and durable roofing system. This approach also contributes to the overall structural integrity and aesthetic appearance of the roof.

While aligning or having irregular joints may seem like valid options, they do not provide the same level of water resistance or durability that staggered joints do. Aligned joints can create direct pathways for water to enter beneath the shingles, while irregular patterns can lead to inconsistent coverage and potential vulnerabilities. Thus, a staggered arrangement is the recommended method for roofing installations to ensure long-lasting protection and performance.