Roofing Glossary

Flashing

Flashing is the system of metal strips installed wherever the roof is interrupted — around chimneys, vents, skylights, dormers, and in valleys — to direct water away from joints and seams. Shingles shed water on open slopes; flashing handles everywhere shingles cannot.

Here is the statistic every homeowner should know: the large majority of roof leaks are flashing failures, not shingle failures. Flashing corrodes, pulls loose, was improperly installed, or was reused past its life during a previous re-roof. The shingles can be perfect while failed flashing pours water into the house.

Flashing comes in many forms — step, counter, apron, valley, and vent flashing — each engineered for a specific joint. Quality flashing work is the mark of a quality roofer; it is fussy, custom metal work that cannot be rushed.

Why It Matters

When a roof leaks, suspect the flashing first. And when getting a roof replacement, insist that all flashing is replaced — not reused. Reused flashing is one of the most common causes of premature leaks on new roofs.

What to Watch For

• Rust streaks or corroded metal around chimneys and vents
• Gaps where flashing meets walls or penetrations
• Leaks that appear near any roof penetration

A Maryland Note

Maryland's older housing stock is full of original flashing on second or third roofs. If your home has had a re-roof without new flashing, have it inspected.

Questions about your own roof? Request a free estimate or call Nucci Brothers Roofing at (301) 458-1003.