Silly Roofing Details – Flashing (Part 1)

Posted by in Construction & Shortcuts | June 03, 2013

Our continuing series of Construction & Shortcuts by Dummies goes on the roof this week to look at flashing.

Proper flashing is a critical detail for all shingled roofs.  Proper flashing is usually comprised of metal or a rubberized membrane.  Flashing is commonly placed where two different exterior surfaces meet, such as a roof and a wall, one roof slope and another, a roof and a chimney, a roof and a skylight, etc.  Flashing is what directs roof runoff away from a joint in the roof surface and reduces the risk of (hopefully prevents)  infiltration.

On the above roof we found what at first appears to be a cut away view of how step flashing should be stepped at each shingle course where the roof surface abuts a second floor wall.  We see that the L-shaped step flashing tins are properly set at each course – very good!  Unfortunately, this is not a cut away view, but someone placed the step flashing over the shingles.  For the record, the step flashing must be placed UNDER each shingle tab.

If you have uncovered an unusual construction detail, please send me a photo and description at