Where should flashing be installed on a building?

Flashing is a critical component in building construction, acting as a barrier to prevent water intrusion. It plays a vital role in ensuring the longevity and integrity of a structure by directing water away from vulnerable areas.

Installing flashing at the perimeters of exterior door and window assemblies is crucial. These areas are common points where water can enter due to gaps or improperly sealed joints. Flashing here helps guide water away from these openings, reducing the risk of leaks and resulting damage.

Additionally, placing flashing at penetrations and terminations of exterior wall assemblies is essential. This includes areas where pipes, vents, or other components penetrate the wall. Properly installed flashing directs water away from these potential entry points, mitigating the risk of moisture problems.

Furthermore, the intersections of exterior walls with roofs or decks are another critical location for flashing installation. These transitions are highly susceptible to water accumulation and can lead to leaks if not adequately protected. Flashing here helps ensure that any water running down the wall is redirected away from the building envelope.

By including all these areas—door and window assemblies, penetrations, and intersections with roofs or decks—flashing installation addresses various vulnerable points in the building's design. This comprehensive approach is why the correct answer encompasses all the options provided.