Bathroom venting out of new siding

**ryan87500** · 09-22-2011, 02:53 PM

I have one bathroom upstairs that is not vented through the roof. It is layed next to the soffit and there is mold there. We are getting new siding put on and the company said they can install a vent cap similar to a dryer one on the side of the house and vent it out of that.

Is that a good solution. They said they would not recommend doing it out of the roof if not putting a new roof on as it can cause complications.

Thanks!

**cacher_chick** · 09-22-2011, 03:04 PM

Any decent roofer can properly flash a new vent onto an old roof.

Are you talking about a ventilation vent or a plumbing vent?

**ryan87500** · 09-22-2011, 03:28 PM

Ventelation vent. He will do it as part of the install so if it is ok to do it this way and I save some money that works for me as well.

**cacher_chick** · 09-22-2011, 06:46 PM

The challenge in doing such an installation is that the vent pipe should not have any dips in it where condensation can pool.

**ryan87500** · 09-22-2011, 08:31 PM

Originally Posted by cacher_chick

The challenge in doing such an installation is that the vent pipe should not have any dips in it where condensation can pool.

So I would just have to run it a little higher than the fan and use something to hold it up. Maybe some sort of bracket on the rafters.

**mrmedic** · 09-22-2011, 08:39 PM

I have installed the type that go under the soffit before and I always use ridged 3 or 4" duct work, That way you don't get it sagging. Also you should insulate the duct if you are in a cold climate so it does not sweat and drip in your attic.

Ron

**ryan87500** · 10-02-2011, 06:14 AM

Originally Posted by mrmedic

I have installed the type that go under the soffit before and I always use ridged 3 or 4" duct work, That way you don't get it sagging. Also you should insulate the duct if you are in a cold climate so it does not sweat and drip in your attic.

Ron

I was thinking about using a fantech in-line fan. Can one be used if just going horizontal and not vertically through the roof?

**jadnashua** · 10-02-2011, 12:52 PM

The in-line fans generally don't care whether they are horizontal or vertical. The only potential problem is if it has a built-in damper. If so, then you'd need to ensure it is oriented properly and rated for horizontal use. I see you don't want a new roof penetration, but soffit vents are not good for bathroom exhaust. A roof vent can be problematic if you have a lot of snow in the winter, though. I didn't have a choice on my townhouse - I went through the roof. Since the bathroom was also windowless, I replaced the original overhead light fixture/fan with one from www.solatube.com. This would require yet another hole in the roof. On a sunny day, it brings in the equivalent of the light from a 300W lightbulb, all for free. Worth looking into.

**ryan87500** · 10-03-2011, 05:57 AM

Originally Posted by jadnashua

The in-line fans generally don't care whether they are horizontal or vertical. The only potential problem is if it has a built-in damper. If so, then you'd need to ensure it is oriented properly and rated for horizontal use. I see you don't want a new roof penetration, but soffit vents are not good for bathroom exhaust. A roof vent can be problematic if you have a lot of snow in the winter, though. I didn't have a choice on my townhouse - I went through the roof. Since the bathroom was also windowless, I replaced the original overhead light fixture/fan with one from www.solatube.com. This would require yet another hole in the roof. On a sunny day, it brings in the equivalent of the light from a 300W lightbulb, all for free. Worth looking into.

Is it possible to vent out of the side of the house and not a soffit? I was thining they would just use one of the caps like for a dryer vent on the siding?

hj · 10-03-2011, 06:03 AM

quote; Is it possible to vent out of the side of the house and not a soffit? I was thining they would just use one of the caps like for a dryer vent on the siding?

Of course it is possible. It is done all the time when a roof termination is not possible, or very difficult.

**mrmedic** · 10-03-2011, 08:11 AM

I did not mean to say to vent it into the soffit. They make a special cover just for a under soffit vent. It vents out each side of the cover. If you have room for the duct in the overhang area they can be pretty easy to install. I have seen no problems at all with these type vent exhaust covers. Remember that you should use insulated ductwork to prevent condensation.