In a previous thread I mentioned that I have a yankee gutter issue. This thread is to replace the roof drain that receives the runoff from those gutter.
Before pictures showing the existing roof drain and what it looks like below the roof deck.
To be honest, I couldn't find any roofer locally who have experience, so I researched it myself and decided I want to use a scupper drain, and hired a roofer who seemed willing to take on the challenge, but have never done one.
I settled on the Zurn Z187 drain at the bottom of this page.
The installation instructions are here but it is not entirely clear.
Here is a picture of the drain.
Here is what the roofer did.
First, he demo the existing portion of the gutter. Cut out the existing metal gutter liner, and the membrane over it.
Here is the existing metal liner that was on top of the gutter, one single piece.
Next, he built a depressed box with 2x4 and plywood to set the scupper drain into. That work is solid, the drain sits nicely in it.
Next, he laid a piece of lead flashing into this box. We debated whether it may be better to use aluminum or galvanized, but he felt better with lead because it is easier to manipulate. The flashing covers around the lip of the drain inlet. Then he applied some mastic over the top of the lead flashing to seal the flashing to the drain. This is where I am a bit confused. I know from the instructions, the flashing goes OVER the perimeter of the scupper drain. I am not sure where this black mastic is involved.
Then he applied some roofing paper on top of the lead flashing, and the roofing paper again goes over the "lip" of the drain. Then he added more of the sticky black mastic, and then threw some granules on top of that.
Then he put the silver colored metal "rim" on top, and secured with the bolts.
This created two problems.
First, between the drain lip and the clamping collar, are now many layers. Above the drain lip is a layer of mastic, then the lead flashing, then more mastic, then roofing paper, then more mastic then granules, then the collar. Is this right? I am thinking, all it is needed is the flashing. The granules, will end up causing leak, I think...right?
Second, because it has so many layers, the clamp collar now sits 1/4" above the bottom of the finished surface. That means there will be 1/4" of water always sitting there. If he just put the flashing over the lip, and cut the roofing paper around the edge of the collar, it will end up being flushed vertically.
So both the roofer and myself are not experienced with this. I looked at the installation instructions on Zurn, and it didn't say.
Would really appreciate some feedback on this. Thanks in advance!