What is the purpose of a metal counter flashing in roofing?

The purpose of a metal counter flashing in roofing is primarily to wrap penetrations and prevent water infiltration. Counter flashing is installed around roof features such as chimneys, vents, or walls where the roof material meets these vertical surfaces. By effectively sealing the joint between the roof and these protrusions, counter flashing acts as a barrier against water, directing it away from areas that are more susceptible to leaks, thus protecting the underlying structure.

This function is critical in maintaining the integrity of the roofing system. If water were to penetrate these areas, it could lead to significant damage, including mold growth, decay of roof structures, and increased repair costs. Thus, the role of metal counter flashing is fundamental in waterproofing and ensuring the longevity of the roofing system.

In contrast, while aesthetic appeal may be a secondary benefit of some roofing features, it does not capture the primary function of counter flashing. Structural support is primarily provided by the roofing framework, and insulation is unrelated to counter flashing’s function, as insulation works to manage temperature and energy efficiency rather than waterproofing.