How many fasteners per bank of shingles must be used for asphalt roofing?

For asphalt roofing, the standard practice is to use four fasteners per bank of shingles. This requirement helps ensure that the shingles are securely attached to the roof and can withstand wind uplift and other environmental forces. The four fasteners create a stable attachment point that minimizes the risk of failure, such as lifting or tearing, which can occur with inadequate fastening.

While some roofing systems may specify a different number of fasteners, four fasteners per bank strikes a balance between sufficient hold and efficiency in the installation process. This approach aligns with building codes and manufacturer specifications, which are designed to enhance the longevity and performance of the roofing system.

Other options, such as two, three, or five fasteners, do not meet the widely accepted requirements and may compromise the integrity of the roof, either by being insufficiently secured or by introducing unnecessary complexity in installation without a significant benefit. Therefore, four fasteners per bank is the most appropriate and recommended choice for asphalt roofing.