Rubber Roof to Sidewall Flashing

This is a homeowner's question posted to an online building forum, not a news story, so there's no policy or program update to report. The person is re-siding a house and asking for advice on a specific, tricky detail: how to flash where an old rubber roof (EPDM) over a mudroom meets the wall of the second story above it. Getting this junction wrong is a common source of leaks, since water running down the wall has to be directed over the roof membrane rather than behind it.

The homeowner's new wall assembly uses a weather-resistant barrier (a water- and air-blocking layer that wraps the sheathing), rigid fiberboard insulation, a small gap behind the siding to let moisture drain and dry, and fiber-cement siding. A materials representative suggested sealing the rubber roof to the wood sheathing with butyl tape, then sticking the weather barrier directly onto the face of that tape to tie the two systems together. The homeowner also noted that old tar paper, left over as temporary protection while removing shingles, is peeling away at the point where the roof meets the wall.

For a homeowner watching your own house, the takeaway is less about a specific product and more about the general lesson: any place where a roof meets a wall is a leak risk, and it needs a real air- and water-barrier connection, not just old felt paper or tape improvised as a stopgap. If you have a similar roof-to-wall junction, it's worth having it looked at whenever you're already re-siding or re-roofing.