Bath Vent

[nelson_bw]

I need to install a new vent in my bathroom, the existing vent does not work and vents into the attic. So i need to install a new vent, and vent it outside either throught the roof or soffit. Which method is the preferred method? And is it possible to install the roof cap during cold temps (I am worried about being able to bend up the shingles and nail the roof cap) Any input is greatly appreciated.

[CAMAN]

Going through the roof or gable end would be the best, but if you are able to keep the vent far enough away from the soffit vent code requires that would work also.

If you go through the roof and are worried about the cold brittle shingles breaking you can always warm them with a heat gun. But if you are able to do it on a warmer and sunny day they should be plyable enough without the heat gun.

Do you have any mold issues in your attic because of it being vented improperly?

[SkunkedAgain]

Until spring arrives, you could vent through an attic vent. Then next year you could create a specific fan vent

[Tom7227]

The big thing that I have been told is to use an insulated pipe to get the air from the vent fan to the outlet. You can find both at the big box stores. Make sure you use the correct one cause otherwise you'll just create more problems. Moisture condenses in the non-insulated pipe and then it gets out and screws up your ceilings and insulation.

[frazwood]

I have installed a handful of these over the last five years. One of the most important things is to use a insulated duct, as stated.

As far as "preferred", it is best to run a solid (not flexible), insulated duct immediately up from the bathroom fan through the roof, using the shortest path possible. That said, "best" is not always possible.

I am certain that you can "legally" (legal = minimum code or better) vent the duct out the soffits or the roof. I haven't heard about using a gable (so I don't know, either way). I would *not* vent into the attic space during the winter... that moisture will freeze onto the sheathing and ruin it pretty quickly.

[upnorth]

The big thing that I have been told is to use an insulated pipe to get the air from the vent fan to the outlet. You can find both at the big box stores. Make sure you use the correct one cause otherwise you'll just create more problems. Moisture condenses in the non-insulated pipe and then it gets out and screws up your ceilings and insulation.

Or is starts to melt and drips back into the fixture and bathroom.

[soldoncass]

If you have a gable end within 12-14 feet, that would be the best place to vent it out. As was mentioned, use a 4 inch insulated flexible pipe, and use an outside vent cover, that matches color of siding. It is important to use something on the outside that shuts, when not in use. Just going to an open roof or soffit vent doesn't work well.

[cavalierowner]

I have never liked roof vents because I have always wondered how well they could work when covered by a snow drift. That said, when I added a vent to my master bath, I went out the gable end that was about 18' away. Because a bathroom vent can't handle that kind of distance, I immediately transitioned the bathroom fan up to 6" and then, just before the louver in the gable end, I installed an inline duct fan and wired it into the bathroom fan so they both come on together. Works great; small children have to carry rocks in their pocket to avoid being sucked into the fan I got the idea from a mechanical engineer who did a similar thing on a commercial project I designed for a clothes dryer exhaust.

[hunter76]

Is there such a thing as a ventless, bathroom vent?

[cavalierowner]

Is there such a thing as a ventless, bathroom vent?

I've never seen or heard of one. But I would assume there isn't because one of the primary purposes of a bathroom vent is to remove moisture.

[marine_man]

I have never liked roof vents because I have always wondered how well they could work when covered by a snow drift.

This is always my concern.. unfortunately I'm stuck with a couple of them at my new to me house... it seems like I always ended up with a small ice dam below the outlet unless I religiously cleared the snow from it. Is there another alternative? I do not have a gable end to route it out.

marine_man

[311Hemi]

I need to do this as well as I have high humidity on the main level of our house.

Is there dripping issues if you vent strait up through the roof from the fan? I have a clean shot strait up but was thinking that all that moisture would collect on the inside of the duct/vent and drip back down to the fan. Because of this I was thinking of venting out the gable end which is only 10-12' away.

Also, if you vent through the roof is there any code requiring the vent to be any certain distance away from other plumbing vents. Thought I had read this somewhere where someone had a bath vent close to the sewer/plumbing vent and was getting some of that air back in the house.

[cavalierowner]

I believe there are also wall fans designed to vent directly thru an exterior wall.

Or if your joists run perpendicular to an exterior wall, you can run ductwork in the joist space and go out the wall. Or if you have the newer open web trussjoists parallel to the exterior wall, you can thread ductwork thru the open joist webs and go out the wall. In either of these cases, you should check with the building inspector to see if there is a residential code about minimum distances from openable windows. I know there is in commercial, but I don't know about residential.

I don't think there is a code distance from plumbing vents, just air intakes and openable windows. Best to check with the building inspector rather than have to redo something.

[IamZombie]

Here's another question.

Installing the bathroom fan in the attic, do you need to put the electrical in conduit?

[frazwood]

Here's another question.

Installing the bathroom fan in the attic, do you need to put the electrical in conduit?

There are more than a few electricians on here, but I can't imagine that the answer is anything but "no". There are tons of wires in my attic that are not in conduit.

[frazwood]

Is there dripping issues if you vent strait up through the roof from the fan? I have a clean shot strait up but was thinking that all that moisture would collect on the inside of the duct/vent and drip back down to the fan. Because of this I was thinking of venting out the gable end which is only 10-12' away.

If you do it correctly, this shouldn't be a problem. And by "do it correctly", I mean that your duct needs to be insulated.

[Mike_Top]

I recommend using 6" flex insulated duct instead of 4", which seems to be the most common for bath fans. You'll get way more flow through the duct which will help get rid of moisture fast, and it will also make up for long runs or bends in the duct. And if you buy 25' of duct but only need 15', cut it down instead of coiling the excess up.

[Tom7227]

Another thing you might want to pay attention to is the noise the fan makes. They have a rating in a thing called "Sones" and the lower the number the better. Of course it costs more to get a lower number. I bought one at a real plumbing supply store that you can barely tell is turned on. It cost over $100 but it was worth it in my opinion. I was not much impressed with the ones on the counters at the big box stores.

[dougger222]

A bath fan or as most roofers call them fart boxes are best vented out a gable wall. If that's not an option through the roof is your only way to go. Attached to a turtle vent or box vent will not do your attic any good in the Winter. Like many have said insulated tubing is a must.

I like to run them with a bend in them so when the flapper is opened and when wind driven rain gets in it won't go straight down to the fan. I said when and not if. The same is true for moisture that can't get out through the vent.

If I had $5 every time I took off a fart box and saw moisture around the vent on the decking I'd be able to get a new LX7!