Bathroom Fan water leak

[Leo]

110 cfm Broan new const. 2006 main (1st floor) powder room. Ceiling water stains from fan about time 2 kids moved in so bathroom use increased 500%. As is first floor, it is not cold in the floor joists so can condensation be the case?

 

[WorthFlorida]

If it exhausts through the roof, it can be a leak if it is only happens during a rain event, if not it is condensation. Check the exhaust pipe, usually 4" of ridged duct work or flexible aluminum duct. It should slope downward if going out the side wall of the home so any condensation can drain outside. The duct should be insulated to minimize condensation.

 

[Sponsor]

 

[Leo]

If it exhausts through the roof, it can be a leak if it is only happens during a rain event, if not it is condensation. Check the exhaust pipe, usually 4" of ridged duct work or flexible aluminum duct. It should slope downward if going out the side wall of the home so any condensation can drain outside. The duct should be insulated to minimize condensation.

4” rigid downslope horizontal run thru side of house confirmed. The vent is 25’ between floors so in a heated portion.

 

[WorthFlorida]

Broan has made dozens of 110 CUFT exhaust fans it cannot tell what type if fan yours might be. Low end units have a small fan and better ones use a drum fan. Drum fan models are very quiet compared to a fart fan. I looked up the installation manual on two fans and they no longer recommend any maximum length of exhaust duct. They only had static air pressure that determines volume of air flow.

About three things that might be happening. I'm assuming the staining is around the exhaust fan?

1) The 24' run is too long causing too much back pressure therefore limits the amount of air flow.

2) There is a damper at the duct connector. Be sure that it is not stuck closed. It it is made of metal you'll usually hear it click around during very windy days. Check the outside vent hood. If it has a damper cover, be sure that is now stuck closed. It could be possible a bird had built a nest at the exhaust hood even with a flapper. This happened my my parents house.

3) When you say kids, are these teenagers that never seem to get out of the shower? We all have at least one in the household. With restricted or limited air flow all that humidity is collecting at the ceiling and it doesn't have to be cold for condensation, it's called dew point. Same as the mirrors fogging over. Perhaps the fan is not running long enough. Install a timer switch for the fan. Some are up to 60 minutes, other 30 minutes. For a bathroom of this size 30 minutes should be enough to run after the shower has ended. For larger bathrooms up to 60 minutes is what we use for our master bath.

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[Leo]

Broan has made dozens of 110 CUFT exhaust fans it cannot tell what type if fan yours might be. Low end units have a small fan and better ones use a drum fan. Drum fan models are very quit compared to a fart fan. I looked up the installation manual on two fans and they no longer recommend any maximum length of exhaust duct. They only had static air pressure that determines volume of air flow.

About three things that might be happening. I'm assuming the staining is around the exhaust fan?

1) The 24' run is too long causing too much back pressure therefore limits the amount of air flow.

2) There is a damper at the duct connector. Be sure that it is not stuck closed. It it is made of metal you'll usually hear it click around during very windy days. Check the outside vent hood. If it has a damper cover, be sure that is now stuck closed. It could be possible a bird had built a nest at the exhaust hood even with a flapper. This happened my my parents house.

3) When you say kids, are these teenagers that never seem to get out of the shower? We all have at least one in the household. With restricted or limited air flow all that humidity is collecting at the ceiling and it doesn't have to be cold for condensation, it's called dew point. Same as the mirrors fogging over. Perhaps the fan is not running long enough. Install a timer switch for the fan. Some are up to 60 minutes, other 30 minutes. For a bathroom of this size 30 minutes should be enough to run after the shower has ended. For larger bathrooms up to 60 minutes is what we use for our master bath.

Leviton Decora Preset Resistive/Inductive 60-Minute Countdown Timer, White R22-LTB60-1LW - The Home Depot

Decora Countdown Timer, 120 VAC, 60 Hz, 1800-Watt Incandescent, 600-Watt CFL, 5 Amp LED, 20 Amp Resistive/Inductive, 1HP, Single pole, 3-way or more locations (with VP0SR). Has 4 preset buttons for 10-minute,

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Kid got married and now both living here. They like long hot showers. There‘s no window. Dew point comment makes sense. Stains are on popcorn ceiling around fan cover. It is the higher efficiency squirrel cage drum style. Damper is plastic and operating as it should. I will get up on the roof soon to inspect the vent. Know this, enough water flowed over the ceiling and down the wall, (bedroom closet) and into crawlspace enough to fill 2-3 coffee cups more than 5 or 6 times earlier this year so am very unclear where coming from. Thanks so much.

 

[WorthFlorida]

Popcorn sucks up water like a sponge. To remove it all you need is a like spray of water and it melts. That is an awful lot of water and I'm doubting that the water is condensation. Seeing stains around the fan cover is not so unusual. Are there an hot and cold water lines in that attic space? A possibility from the valve body to the shower head has a small leak so it only shows itself when in use. I've had that happen to me in my last home. Condensation down to the crawl space is doubtful.

At the shower head slide the shower arm flange down the pipe and take a lot at the inside the wall for dampness. You can remove the valve body cover to look inside the wall. In the crawl space look for mold or water stains.

 

[Jadnashua]

You want the duct to slope down to the outside. In 24', ideally, you'd have 1/4" per foot, so 6" drop...it would need to go vertical for at least 6", then slope down to the outside to ensure whatever condensation that might accumulate flows out rather than back down into the ceiling. Plus, if the seams aren't well sealed, moisture could escape from any seam(s) where water might condense.