International Flashing Awareness Day 2025 – GreenBuildingAdvisor

By Randy Williams | August 26, 2025

The International Flashing Awareness Day began in 2021 to create awareness in the industry about the importance of correct flashing of building materials and assemblies. Today is the fifth anniversary of the event created by Aron Jones (Big Dog Construction) and Gena Hoyt. Thanks to the duo for their efforts and dedication in helping to educate the industry. This year, the event is sponsored by Big Dog Construction, Siga North America, Huber Engineered Woods, Off Site Dirt Network, Benjamine Obdyke, York Flashings, Westlake Royal Building Products, and Sashco.

What is flashing?

This is the question I asked of ChatGPT, here’s the definition I was given:

“Flashing is a thin, impervious material—often made of metal (aluminum, copper, galvanized steel), rubberized asphalt, or flexible membranes—used in building construction to direct water away from vulnerable areas of a structure and prevent it from entering the building envelope.

It is installed at key transitions, joints, or penetrations where water intrusion is most likely, such as:

• Roof edges, valleys, and around chimneys or skylights

• Window and door openings

• Wall-to-roof or wall-to-foundation connections

Flashing works by overlapping layers of building materials in a way that uses gravity to shed water toward the exterior, ensuring that water always flows to the outside of the assembly.”

I’d say ChatGPT got the definition pretty much right, but here’s the illustration it created with the definition showing where different flashings are used on a home:

The opening quote by Martin Holladay is right on cue, “of all the construction-related topics that young builders need to master, one of the most confusing is flashing.” I also wonder how many experienced builders are confused by flashing details, it appears ChatGPT is.

All joking aside, here’s my attempt at…