Soot around the bathroom vent

[lclark]

Has anyone ran across this before? The photo is kinda far away. I didnt take a close up, but you can see the black around the vent. This is an upstairs bathroom. The fan was running allright with no problems. There was also what appeared to be soot at the ridge vent above the two upstairs bathrooms. The attic was clean what I could see of it. I could'nt get all the way in due to a closet organizer. I do know that the owner is a cigar smoker. If he smokes in the bathroom with the fan on, could this cause this?

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[Doug Edwards, CMI]

What kind of heating was in the house?

[lclark]

Forced air w/ electronic air cleaner.

[Doug Edwards, CMI]

I can't say what that is or the cause of it. I thought briefly if they had some kind of fossil fuel heating that may be causing the sooting. A friend of mine installed a propane gas log set up in his home and immediately started having sooting problems. The only thing I can think of and its just a guess is that fan is doing its intended purpose and removing humidity from the bath and at the same time may be depositing the moisture onto the surface around these vents, than the dark soot is collecting on the moisture. I have seen in homes where there are heavy smokers where the nicotine in the smoke will collect on the moisture droplets in a bathroom and turn the wall dark brown. The moisture droplets on the cool surface act like a collector. It is a nasty looking mess too so you may be onto something with the cigar smoke. If you find out keep us posted.

[lclark]

Thanks Doug, makes sense. They do have a gas log setup in the fireplace. Its natural gas. They may be using the fireplace with the damper closed. The room with the fireplace has a vaulted ceiling with an open balcony to the upstairs. It would make sense, if the bathroom vent fan was on, it would draw the soot an smoke up to the bathrooms and out the vent.

[Brian E. Kelly]

Originally Posted by lclark

Thanks Doug, makes sense. They do have a gas log setup in the fireplace. Its natural gas. They may be using the fireplace with the damper closed. The room with the fireplace has a vaulted ceiling with an open balcony to the upstairs. It would make sense, if the bathroom vent fan was on, it would draw the soot an smoke up to the bathrooms and out the vent.

If the fireplace has a gas log the damper should be blocked open with a damperstop or the damper should have a knockout. This is an unsafe condition as described.

[Stephen W. Stanczyk]

I've seen this once or twice in my area. Turned out to be "a mold like substance". The increased moisture stayed right around the vent and stained the siding. Never enough to cause drips but enough to discolor. Was this on the dark side of the house?

Of course Washington is known as the Evergreen State because we are all covered with moss and algae. WHERE IS THE SUN?

[Robert Alexander]

There are numerous causes for this as this thread indicates. The first question I have is, "Do you know for sure if it is soot?"

The most common cause for soot or soot-like substance around the vents is the homeowners not changing the filters often enough. This is especially true in homes where they have pets and/or smokers.