Oregon Construction Contractors (CCB) Practice Test

Corrosion-resistance flashing must be used in all specified locations except:

1. Surrounding roof drains

2. Under window sills

3. Surrounding all interior bedroom doors

4. At exterior wall intersections

The correct answer is: Surrounding all interior bedroom doors

Corrosion-resistant flashing is an important building element designed to prevent water intrusion and damage to structures. The use of such flashing is particularly critical in areas that are most susceptible to water exposure and potential corrosion. The correct answer, indicating that corrosion-resistant flashing is not needed around all interior bedroom doors, makes sense because interior doors do not typically experience the same exposure to moisture as exterior components do. Unlike exterior openings, which are directly exposed to the elements, interior doors are located within a controlled environment where they are less likely to encounter water or dampness. Thus, the structural requirements for corrosion resistance in these locations are not as stringent. In contrast, flashings around roof drains, under window sills, and at exterior wall intersections are all key areas where corrosion resistance is essential. These locations deal with significant water exposure and drainage issues. For instance, roof drains are critical for directing water off roofs, and any flashing surrounding them must prevent moisture from seeping into the building structure. Similarly, window sills are prone to water from precipitation, necessitating flashing that can withstand corrosion. At exterior wall intersections, the potential for water to infiltrate through seams and connections further underscores the need for corrosion-resistant materials.