Replies

1. 
   nigelUsa | Sep 02, 2002 11:42pm | #1

   shorter is better, and to the outside is best. a side wall is fine for venting. panasonic make a range of fans that run very quite. Much less noise than the very best nutone

2. 
   rjw | Sep 03, 2002 12:07am | #2

   As noted, "shorter is better, and to the outside is best. a side wall is fine for venting"

   IN NW Ohio I often see bathroom vents discharging into the attic with no apparent problems -  but maybe they aren't being used!

   In my area they are frequently nailed off to the framing right below a through roof vent, and I've never seen one of those with signs of problems.

   But then again, sometimes I'll see lots of mold and sometimes rot when they are improperly vented, as seen in tha attached picture (you can see the bath vent discharge just behind the waste vent stack.)

   
1. 
   rez | Sep 03, 2002 03:20am | #3

   Doesn't that photo make you feel like crawling around up there and working. Preferably on a summer day.Half of good living is staying out of bad situations.

1. 
   brownbagg | Sep 03, 2002 03:47am | #4

   I talk to the mechanical inspector about this item. He claimed that it is legal to exhaust into the attic. With codes coming out every which way they must thing its safe. On mine, I went to the ridge vent, it ehaust out side but just under the ridge vent cap.

2. 
   nigelUsa | Sep 03, 2002 05:38am | #5

   Venting into the attic from a hot steam shower on a cold wet day will sometimes lead to condensation on the underside of the roofing. This is what causes the mold and could lead to damp rot. A well vented attic might be ok.

1. 
   rjw | Sep 03, 2002 10:26am | #6

   Yep, that's what the pic shows, and you're right, it's only sometimes: more likely on a north slope, mopre likely lower down, I think more likely on plywood or OSB but can't prove the last.

3. 
   TLRice | Sep 03, 2002 03:16pm | #7

   It is usually less expensive to vent out the side than the roof, if the duct runs are similar, and you eliminate the potential leak of a penetration though your roof.

   Whether it is legal or not , it is a bad practice to vent anything into the attic, and it is not "ok". Do it right and you'll never regret it. Vent into the attic may not cause any problems, but why gamble.

   Several manufacturers make exhaust fans that are meant to be remotely located.

1. 
   snharris | Sep 04, 2002 02:15am | #8

   Thanks for the input, I will vent to the side wall.

4. 
   goldhiller | Sep 04, 2002 06:32am | #9

   SN,

   Since you're in the NE, I'll assume you encounter winter temps and so you'd want to adequately insulate that vent pipe or water vapor will condense inside during the winter and run/drip back to your ceiling. I've seen more than one uninsulated vent pipe completely blocked with ice.

1. 
   snharris | Sep 05, 2002 04:04am | #10

   Thanks, thats a good point. Wrap with insulation or styrofoam?

   STEVE

1. 
   goldhiller | Sep 05, 2002 04:50am | #11

   We usually wrap the pipe with some R-13 fiberglass insulation in a spiraling fashion and some long plastic zip ties or light wire around it to hold it in place. We try to get it secure without compressing the insulation anymore than is necessary, but enough to make certain it's secure so it won't slide down or come undone. If you're using metal pipe for the exhaust (which I'd recommend, rather than the plastic flex type), you might be able to find some preformed sleeves used for HVAC that are made for this purpose, but frankly we've never bothered to look as this gets the job done nicely. If you want to really do it up, you could apply some metal foil tape around those joints in the pipe, if there are any in your installation.

1. 
   wlai | Sep 05, 2002 08:08am | #12

   There was a recent issue of Fine Homebuilding that talked about Fantech attic-mounted exhaust fans.  Currently I have two ceiling mounted fans, venting straight up thru the roof, and I'd like to replace them with one Fantech unit.   How should I go about patching up the extra roof vent that's no longer needed?  The roof vents doesn't seem to have any leaks, so I wasn't going to patch both roof vents and relocate the vents to a side wall.  But given what is said about venting side walls, is that something I should consider?

   Thanks

1. 
   TLRice | Sep 05, 2002 02:44pm | #13

   One thing to consider is that the two individual roof jacks are most likely 4". A 4" roof jack is not good enough to exhaust 2 bathrooms. The comment I made about the cost and the penetration of the roof was based on having the option to do one or the other, both being a similar distance. Wall jacks are less expensive than roof jacks. There is nothing wrong with going through the roof. Its done all the time, and flashed properly, never leak.

2. 
   TLRice | Sep 05, 2002 02:45pm | #14

   2" foil-faced insulation for ducts is the stanadard, with taped or stapled and taped seams.