Coil flashing is primarily used to protect vulnerable areas on a roof, specifically around features that penetrate the roof surface, by directing water away from the roof deck.
Understanding Flashing
Flashing is a critical component of a roofing system designed to prevent water penetration. It acts as a barrier and a channel, diverting water flow to keep moisture from seeping into the building structure.
The reference states: "Flashing is installed to surround roof features, such as vents, chimneys and skylights. Water should run down the side of the flashing and be directed to the shingles instead of finding its way into the roof deck."
Key Uses of Coil Flashing
Coil flashing is often made of materials like aluminum, copper, or steel, and is supplied in rolls (coils) for easy shaping and installation on-site. Its main purpose aligns directly with the function of flashing as described in the reference.
Specific applications include:
- Surrounding Roof Penetrations: It is shaped and installed around elements like:
- Chimneys
- Vents (plumbing vents, exhaust vents)
- Skylights
- Pipes
- Walls that intersect the roof plane (like dormers)
- Creating Watertight Seals: The flashing creates a seal where these features meet the roof, preventing water from entering the gaps.
- Directing Water Flow: It is strategically installed in layers with roofing materials (like shingles) to guide water downwards over the roofing surface, effectively diverting it away from the roof deck and interior of the building.
Essentially, coil flashing provides the flexible material needed to custom-fit this essential water barrier around the irregular shapes of roof features.
| Roof Feature | Flashing Function |
|---|---|
| Chimneys | Seals base, directs water around and down |
| Vents | Seals base, prevents leaks where pipe meets roof |
| Skylights | Seals frame, channels water away from glass and frame edges |
| Walls | Creates a seal at the intersection, often using step flashing |
By installing flashing correctly, particularly around features highlighted in the reference, roofers ensure that water runs down the side of the flashing and is directed to the shingles rather than compromising the roof deck.
