Pan flashings don’t necessarily just have to be around skylights. Many walls utilize this same detail. Today in Vancouver we cleaned a long pan flashing along an exterior wall. The debris build up in these long pans is always substantially more then in smaller skylights. Make no mistake they all need maintenance or they will all leak. It’s just these larger pans will fill up with debris faster and thus leak at a higher rate due to the amount of roof they are covering.
We were working in Vancouver today and the task was a pan flashing maintenance. Through our work, we modified the detail to be more accommodating. Let me explain. You’ll notice we used 3 lead cover sheets on the right hand side of the skylight. Previous to our work, there were small “sliver” tiles placed in the pan flashing to continue the horizontal row of tiles to the curb (vertical wall) of the skylight. These sliver tiles were in fact counter productive. They were blocking up the pan flashing and acting as dams to collect and stop the debris the rain was washing down the roof.
By not reinstalling these sliver tiles we have now “opened up” the capacity of the pan flashing and the probability of it getting blocked with more debris in the future is now greatly reduced. Waterproofing integrity is still at 100% even without the sliver tiles. We have had nothing but success using this strategy.