Roof Flashing Flashcards
What is the importance of roof flashing in a roofing system?
Roof flashing is crucial for preventing leaks. Even if the roof covering is new, improperly installed or poor-condition flashing can lead to leaks.
Where is flashing necessary on a roof?
Flashing is needed at any interface between a roof plane and another component, including:
Other roof planes
Walls
Chimneys
Vents
Skylights
What is counter-flashing?
Counter-flashing is a secondary flashing that overlaps the primary flashing to provide extra protection against water intrusion.
What materials are commonly used for roof flashing?
Galvanized steel
Copper
Aluminum (not recommended for coastal areas)
Lead
Stainless steel
What are the main types of roof flashing?
Edge flashing
Ridge and hip caps
Valley flashing
Roof-wall flashing
Roof-roof flashing
Chimney and vent flashing
Skylight flashing
What is edge flashing (drip edge) and its function?
Edge flashing, also called drip edge flashing, prevents rainwater from wicking into the roof sheathing or decking. It ensures drips fall away from the roof structure.
What does the 2018 IRC Section R905.2.8.5 require for edge flashing?
Edge flashing must:
Be installed at all eaves and rake edges
Extend at least 1/4 inch below roof sheathing
Extend back onto the roof deck at least 2 inches
Be fastened to the roof deck every 12 inches
How should the underlayment and drip edge flashing be installed at the eaves?
The underlayment should overlap or cover the drip edge flashing to protect it.
How should the underlayment and drip edge flashing be installed at the rake edges?
The metal drip edge should overlap or cover the underlayment to prevent wind-driven rain from entering under the underlayment.
What is the purpose of drip edge flashing at the eaves?
At the eaves (gutter location), drip edge flashing protects the roof deck by ensuring rainwater flows away from the roof sheathing. It is covered by the underlayment, often a “peel-and-stick” or “ice and water shield” material.
How is drip edge flashing installed along the rake edge of the roof?
At the rake edge, the metal drip edge flashing is installed on top of the underlayment to prevent wind-driven rain from getting underneath.
Why might it be difficult to see multiple layers of shingles on a roof?
A second drip edge flashing may be installed with a second roof covering, hiding the additional layers of shingles. Inspecting at the eaves is necessary to identify multiple layers.
What are ridge and hip flashings, and what are they made from?
Ridge and hip flashings, often called ridge caps, are made from the same material as the roof covering. Examples:
Asphalt shingles: Cut-down 3-tab shingles or special ridge shingles
Slate tiles: Terra cotta or metal (copper/lead)
Wood shakes/shingles: Special ridge caps, trimmed shingles, or cedar planks
Clay/concrete tiles: Specially manufactured caps, nailed or mortared
What is the correct size of asphalt shingle ridge caps?
Asphalt shingle ridge caps should extend 4 inches down from the roof peak on both sides.
What materials are commonly used for ridge caps on different roof types?
Asphalt shingles: 3-tab shingles or special ridge caps
Slate tiles: Terra cotta, copper, or lead
Clay/concrete tiles: Specially manufactured caps
Metal roofs: Ridge caps matching the roof style
