← U.S. Residential Roofing Basics
Flashing, valleys, and roof penetrations
By the end: Describe why roof intersections need dedicated water-management details.
Flashing directs water at joints, edges, and openings. Common locations include roof-to-wall intersections, chimneys, skylights, plumbing vents, and valleys. Think about continuity: water leaving one surface needs a reliable route onto the next drainage surface, rather than behind it.
Step flashing is associated with successive shingle courses at a sidewall. Counterflashing protects the upper edge of certain flashing assemblies. A pipe boot addresses a pipe penetration, while drip-edge metal manages an edge. These names describe roles; the correct combination, overlap, fastening, and compatibility are system-specific and must be designed and installed correctly.
“We will caulk it” does not explain how the detail sheds water. Sealants may belong in specified details, but a bead of sealant is not a substitute for understanding the drainage path. A solar attachment is also a roof penetration when the chosen system penetrates the covering. Roofing and solar contractors must agree who owns that interface.
- Scenario: a stain appears on the ceiling below a roof-to-wall intersection after wind-driven rain.
- Ask the contractor to inspect the interface and document the cause, not just coat the visible stain location.
- Request photographs of the repaired detail and the product-specific instructions used.
Quick check
A solar mount penetrates the roof. Which question addresses the key interface?
End of module 2