Hi,
I have two bathrooms on the second floor of a colonial with no bathroom fans in them. I’d like to install them to vent out the moisture. A friend bought a similar home in a nearby neighborhood, and their bathroom fans vent into the attic, but not outside. I’m wondering if you have any opinions on whether that’s a good practice. It would seem to me that venting outside would be preferable, but is there a problem with venting directly into the attic?
Thanks in advance..
S
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Do Not Vent Into The Attic!!!!!!!
The reason you want to vent, is to get moisture out of the house.The attic is still part of the house.
Hope this helps.
Well put. Gets right to the point.
I completely agree! Do not vent in to the attic! Take the extra time and vent through the roof. Although I'm not a big advocate of roof penetrations (even if done right) It's far better than the moisture build up, eventual mold and decay your roof strucure is sure to encounter
Soap
A related question, what about venting out of the sidewall? Is that an okay way to go? I'm in the same situation, with two unvented bathrooms both situated on a gable end wall where I could go up into the attic and directly out the wall through vinyl siding. No roof penetrations necessary. Is that acceptable?
Bart
Sure, you can go out thru the side or down from a soffit. Code requires such outlets to be some distance from any window, door, or lot line. I think the number is 3 feet, but check if you need to know for sure. Run smooth PVC with the horizontals sloped to drain outwards.
-- J.S.
I don't think venting out a soffit is a good idea. I recently worked on an article with Mike Guertin about this particular subject as he explained it to me soffit vents are one place where the house breaths. Vapor exhausted there might (or probably will) get sucked right back into the attic. Vent out the roof or gable end wall.
Brian P.It's my job!
OK, I can see how that could be a problem in many cases. The one I remember seeing that was done that way was OK after about 30 years. The walls and underside of the soffit were stucco, and the location was near the ocean, so there was almost always a good breeze. It depends on the specifics of each house. About the only advantage I can see to using the soffit is that it's the least likely to leak in the rain, and we get hard wind driven rain at the coast.
-- J.S.
Talking about bath fans makes me think of one of the truss plants I worked at.
The office was in the corner of the plant. Since the plant had 16' ceilings, the office was built with 8' walls and a floor was put on top for storage.
The bathrooms in the office had fan/light combos in them, and they appeared to work.
One day a cat found it's way into the space between the ceiling and floor above and died. Wasn't too long before the smell became pretty bad in the bathroom areas. We turned the bath fans on and let them run, but it didn't seem to help. It actually seemed to make the smell worse.
Eventually we had no choice but to go upstairs and tear up some flooring to find the dead cat. After the cat was removed we found that there were no ducts hooked up to the bath fans - They just blew air into the joist space. Dr. Kevorkian for White House physician.
We had a problem like that for a while with pigeons nesting in the duct for the bathroom exhaust. When someone turned on the fan, it would kill a bird, which would then stink, and jam the fan. For a while we used to beat on the duct before turning on the fan. The studio insisted on waiting until nesting season was over before screening the damned thing.
-- J.S.
Venting through the wall is fine. There are code requirements in doing this, however. Make sure you check requirements for your area they very greatly region to region.
Your fans should be vented outside. Pumping warm humid air into your attic is never a good idea, it will only lead to problems with mildew and eventually.........rot. If your ductwork for your fans is going through unheated space you should also insulated the ducts or else the warm moist air going through the ductwork will meet the cold unheated air and cause condensation which can lead to more problems as well.
Run the vents completely out of the house....avoid penetrating roof....avoid flexible (ribbed) ductwork.....minimize bends and turns....pitch ductwork to the outside and wrap with insulation.
J. D. Reynolds
Home Improvements
"DO IT RIGHT, DO IT ONCE"
I vented mine into the attic because it meet code, after spending weekend with bleach and a brush in the attic. I cut the roof.
I,m Sorry, I was wrong, cut the roof.
Beside everybody knows the county are not that smart on code item. venting into attic does not work.
Hang on everyone.... Venting bath room fans is venting !!! It may be done horizontally or vertically... Code does not permit bath room venting to inside of house !! Except for those stupid enough to buy into venting CO2 from the fire place back into the living area or hood venting fumes through some type of filter then back into the kitchen. Ribbed or smooth, it truly does not really matter... Venting through the gable is fine if you can find the correct attaching hardware. Agree that you should not penetrate the roof OR try to tie into another vent pipe that may be a waste vent. You can even use one of those neat exterior vents for a dryer and cut a hole through the side wall of the attic.... But if you have varmits, you might get an uninvited visitor....
Ken in Savannah
Thanks everyone.. i'll run insulated ductwork to the attic roof or gable, and out there. I appreciate the advice!
> Ribbed or smooth, it truly does not really matter...
Except maybe on horizontal runs if the potential for condensation exists. In that case, smooth and sloped to drain outward is what you want.
-- J.S.
js
Never have seen a condensation problem with ribbed. As long as the fan is used and air moves through the vent, there won't be much of a chance for moisture forming as any minor condensate material will evaporate....
Also, venting to a soffit vent is fine also.
Ken in Savannah
Ken, when was the last extended period of below freezing weather there in Savannah?
Warm moist air entering a cold pipe will condense onto the walls of the pipe. There is a LOT of water in that air.
Joe H
JoeH
around 18300 BC.
But, I still need convincing that the air moving through the vent is not enough to vaporize the moisture... What happens to vents running through the roof, straight up ?? Does the moisture fall back into the room ??
Ken
Yes. It happens. And at most times, the air moving through the pipe that you are assuming is going to evaporate the condensation is in a cooling state. It will not be absorbing more moisture from the condensate already in the pipe.
Joe H
We moved into our house in the fall after it was constructed (spec house). Two months later, while standing in the master bath following a shower, I got drenched by water pouring from the vent fan. (Okay, it was a couple of tablespoons, but it felt like a bucketfull.)
I climbed up into the attic to find the uninsulated plastic hose from the fan nearly vertical, the end nailed next to the gable vent, in the idiotic hope that the air/moisture would find its way outside. That's when I learned how much moisture was in the air after a shower and how it can condense on a cold New England evening. The vent is now insulated, canted toward the exterior, and is vented out the wall 4 feet below the gable vent.
I've since installed many fans myself, and have never had a similar problem. Insulate, slope the hose, vent outside; you can't go wrong. (And use the bird-cage thingys to keep out the critters.)
I never met a tool I didn't like!
Was still curious and talked with the tech reps from Broan.... They say ribbed or smooth is ok also !!! (even in cold weather) makes no difference as long as insulated if in a cold unheated space .... They state the main problem is that users turn off the fans too quickly... Should be left on 15 minutes after leaving the room.....
Ken in Savannah
A bath fan doesn't have to be on a gable end but that may be an easier place to place the hole. Through the roof sounds like a lot of unnecessary work. Try to direct it the shortest, straightist possible route. You can option exhaust on the the units 90 degrees so the vent will chase the joist bay and out the gable end or eave. I usually try to put it in a dark and obscure place because the exterior vents look cheap and ugly. I don't think the 3' from a window rule applies either because it is not a gas appliance exhaust. If you have exposed rafters then you can vent out the frieze block. If you have a soffit then run the flex hose or hard pipe if that is "Finer" out the soffit and not into it.
Condensation and code issues are very regional. What's a winner in Las Vegas might not cut it in New Orleans. The bathroom fan isn't venting combustion products, but it can be venting ... shall we say ... odors. That's why there may be a distance-to-window code. Check with your local bldg. dep't. for the rules that apply to your job.
-- J.S.
and dont forget to slope the outside end of the (insulated) vent tube DOWN a few degrees so condensate drips outside rather than back down the tube and into the fan...
I have been reading any thread that has to do with bathroom ventilation and ventilation in general. I was just wondering what y'alls thought on this are.
I have an old (1904) house with the back section being a gable end. The bathrooms are both in this gable end as is the kitchen. I am putting Icynene under the new roof deck as well as in the walls, so my envelope is on the exterior walls.
There is a gable end vent opening that is no longer needed and something I would be closing up now that the envelope includes the entire area under the roof. I was thinking of using a remote fan located under the roof to serve both bathrooms and thought I could vent it out of the gable end vent instead of just closing that off.
Does this make sense? I was concerned that it might cause the painted siding to blister and peel around it. I was also considering putting a HRV system and a continually circulating system up there but, even with the Icynene, I have to wonder if an old house with 30 windows is ever going to be so tight as to justify the controlled vebntilation.
OK, thanks in advance for any replies.