Which statement about counterflashing is true?

Which statement about counterflashing is true?

• A. Counterflashing is installed over base flashing to seal seams
• B. Counterflashing is installed under shingles
• C. Counterflashing is the folded segments installed with shingles
• D. Counterflashing is not used with metal roofs

Answer: (A)

Counterflashing is the metal piece that covers the seam between the wall and the roof to keep water from leaking behind the flashing. The main idea is that it goes over the base flashing to seal that seam, creating a continuous barrier as water runs down the roof. In practice, you install base flashing along the wall first, then place counterflashing over it and seal it, with the shingles laid over the counterflashing. This placement directly prevents water from penetrating at the joint where the roof meets the wall. The other descriptions miss or blur this critical relationship to the base flashing and seam protection, and counterflashing is used with a variety of roof types, including metal roofs.

Counterflashing is the metal piece that covers the seam between the wall and the roof to keep water from leaking behind the flashing. The main idea is that it goes over the base flashing to seal that seam, creating a continuous barrier as water runs down the roof. In practice, you install base flashing along the wall first, then place counterflashing over it and seal it, with the shingles laid over the counterflashing. This placement directly prevents water from penetrating at the joint where the roof meets the wall. The other descriptions miss or blur this critical relationship to the base flashing and seam protection, and counterflashing is used with a variety of roof types, including metal roofs.