You'd just have a leak in a different part of the house

Agreed.
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bc

Sounds like you'll get it fixed. Good luck, and stay dry :)

OK, here is a real "out there" idea, what if there is a leak on one of the round roof vents, and the previous owner installed this tubing as a drain? Who knows, maybe they had a bucket at the other end of the vent! You should be able to test this idea with a volunteer and a hose. Go up in the attic with a really good flashlight, and have your volunteer aim the hose to rain on the vents, do not spray directly on them spray above and let the water fall on them like rain. Then look in the attic for water dripping.

Good luck, hope this helps.

Interesting thought but beyond my capabilities to test. My duct theory seems possible, but I'll admit, a bit unlikely. It seems there ought to be a simpler explanation, but I just can't come up with one. As an aside, how are gas hot water heaters supposed to be vented, anyway? Is it even possible that it what the duct is for?
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bc

Electric HW heaters are not vented. Natural Gas HW heaters are generally vented by a rigid vent pipe through the roof. It depends on the layout of your house, but as a rule, this is the norm. Tankless HW heaters require a larger diameter vent than standard tanks.

Not to belabor this, but I just took a much closer look at the duct in question and I now believe it is the venting duct for our gas furnace and not for the water heater. The two are fairly close together in the garage and there's lots of blown-in insulation in the attic covering everything so it was difficult to see exactly where the duct ended. The duct coming out of the furnace also looks like the right diameter, whereas the vent from the water heater is narrower and does appear to go straight up (we have gas for the dryer and heat so the now missing water heater was in all likelihood gas as well).
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bc

I would just look in the attic the next heavy rain storm and see if you can see where the water coming from. Even after the heavy rain you should see wetness. Especially how it’s getting down into the wash room.

I'll do that the next time that happens in the daytime. I'm not really a get up in the middle of the night person. :icon_wink:
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bc

One other question occurred to me. How are vents for gas furnaces supposed to be done, anyway?
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bc

Ok, nevermind about the furnace questions. I braved the attic one more time and had a much longer look at everything and its clear now the duct I was referring to is from the master bathroom, probably the exhaust fan vent.

I came to that conclusion after I observed that there's another identical duct at the other side of the house where the guest bath is that leads up to the same area. I simply hadn't noticed it before. I've attached a picture. Interestingly, the duct for the guest bath runs all the way up into the space just below the circular vent whereas the one for the master bath does not, it is just hanging in space several feet below. That should probably be fixed, but I can't imagine how anyone would get up in there to do that, especially with all the blown in insulation lying about. The master bath duct does pass over the area above the laundry ceiling and the place where the two sections of it is joined is right there, so it could still be involved I suppose.

On the other hand I also noticed this time that there's a large metal pipe in roughly the same area that leads up to the roof. It is the topmost gooseneck vent in the original picture (the lower one being the dryer vent). I'm not sure what that could be for. Could it be for the kitchen oven? That's right on the other side of the laundry room wall. I'm fairly certain that the roofer who was here in January worked on that area already, but perhaps it needs more attention. Maybe the vent just needs to be replaced. Upon further reflection, this seems somewhat more likely than the somewhat far-fetched master bath duct theory.

Though I was an engineer, I'm not the handyman type (bet you couldn't tell :1rotfl:).

We'll see what they say next week. Thanks for bearing with me ...
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bc

P.S. For the record, the second and third pictures are of the actual leak and the water on the floor after the storm earlier in the week. It's clearly not a huge leak, but has to be fixed regardless.

Ditto in our designer (when new). It took a year of roofer vs plumber arguments, but finally warranty stepped in and made someone come out and fix it. The vent angle needed to be changed. That solved the problem.

It looks like the builder ran the two bathroom exhaust ducts to the area just under the roof vents. This is probably okay, but, In the newer houses, they run the bathroom vent to the outside soffit and connect them to a hole that they cut into the soffit. I have even seen older houses that just vent the bathrooms into the attic space, and depend on evaporation to eliminate the moisture. But, it could be that your master bath duct has a low point above the laundry room, and the ceiling leak could be just an accumulation of moisture in the duct from the master bathroom exhaust fan that runs down to the low point and creates a leak. If that is the case, then you need to eliminate the low point by possibly installing a hanger to lift up the duct. This is just my opinion about what could be happening. Another solution could be to reroute the master bath duct to the nearest soffit location with hopefully a shorter run. Good luck.

One other point is that, if the bathroom exhaust duct is a long run, then the exhaust fan may not be strong enough to push the damp air to the end of the duct. In that case, all of the moisture from the bathroom will stay in the duct and run to the low point. This problem could be worse when it rains because of the increase in humidity in the attic.

The bathroom ceiling fans ducts are probably venting the the odors to the attic when you turn the fan on, I doubt the are attached to anything? In older home they don’t have ducts in attic the just vent up there.