14 year old house recently reroofed due to hail damage. Later on, a
leak was discovered at the furnace vent on the roof. It must have been
leaking awhile, onto a 4x8 chipboard floor under the furnace, but this
last rain was enough to cause enough problem to get attention.
The gas furnance is in the attic (Texas), and the leak was around the
vent pipe itself, at the thin gap between pipe and top of conical metal
flashing. From inside, there was a thin ring of daylight visible at
this small gap around the vent pipe where it goes through the flashing
dome. There is a loose rain deflector ring outside on the pipe above,
sitting on the flashing dome, but the rain was running down the pipe
The gas hot water heater vent is built similarly, also with a minor
leak, but the larger furnace vent was leaking much more.
I dont know if the roofing job needed to mess with the top of the
flashing cone (where it was leaking), but I called the roofer back out,
and he said they should have sealed it. He put a black sealer goop on
it. I think he called the sealer something like MP3 (not all sure I
Is this how it's done? I assume the furnace vent gets warm, although
probably the outside air cools it. Will such sealer last several years?
Anyone know of a web site with illustrations how such flashing and vents