The offices under this curved glass roof had been getting wet for years. The drops of water usually came down days after the rain — not surprising, given the height of the brick wall above, a likely water reservoir. I started with some controlled testing and discovered that water was showing up inside about 10 feet away from an area where I could see a lap in the metal through-wall flashing outside.
Next I called for removal of the drywall ceiling to further narrow the possible entry location. From what I could see inside, I suspected that the laps in the flashing had failed, if they ever worked in the first place. We had no choice but to rent a bucket truck and — very carefully, considering the glass below — start deconstruction.
We first uncovered the suspect lap joint, which — sure enough — was not sealed.
I also pulled off the brick at the end of the solarium, pretty sure that I would find no end dam in the flashing there. Without dams, water would eventually make its way down into the walls at each end.
When the roofing contractor did the repair, he soldered the new copper flashings wherever he could, and sealed them with Carlisle’s Water Cut-Off Mastic, a clay-based caulk that effectively stops water as long as it’s in compression and out of direct sunlight.
For good measure, we also added a layer of uncured rubber membrane over the flashing laps. . . .
. . . and at the ends of the flashing. It’s been years now and they’ve not had any leaks since.