Dryer vent routing

[stranger706]

So our laundry room is in the middle of the house (single story).

The dryer vent goes down into/under the slab foundation, runs about 20 feet straight out, comes up and exits outside the exterior wall. The entire vent is 4" pvc. For 5 years, we haven't had any problems with it and I clean it out once a year. Sometime this past year, the line has cracked somewhere underground and whenever it rains, the line fills up with water for a day or so, unless I shop vac it out. This gets old fast with the amount of rain we've had lately.

I understand this is not a popular method of dryer venting and is only allowed in some states. I don't know why the builder chose this method.

I want to plug this line and install a new line on a new route. I would like to go straight up from the dryer into the attic, then over to the eave and install an eave vent. I could also go sideways out into the garage, and then over to the exterior wall. Both would be about the same length. I plan on using rigid metal lines and fittings.

Any advice or comments would be appreciated.

 

[dave180]

+1 on the rigid (smooth inside wall) pipe. If it were me I would look for the best and shortest route to go horizontally through an outside wall. I would shy away from trying to do a vent through an eave.

 

[LotI]

Stay under 75' equivilant venting for most brands. Every elbow is ~10ft and the wall cap is about the same. A single 45* elbow could be ignored but two counts as 90*

See the 2nd page

 

[EA82]

Yep and over 25' they recommend a booster fan, at least that's new construction code here.

 

[stranger706]

Originally Posted By: dave180
+1 on the rigid (smooth inside wall) pipe. If it were me I would look for the best and shortest route to go horizontally through an outside wall. I would shy away from trying to do a vent through an eave.


Horizontal would mean going out to the garage (through the insulation/moisture barrier) across the back of the garage and through the exterior wall (which is brick).

Any code problems with this? (Alabama)

 

[dave180]

Originally Posted By: stranger706
Originally Posted By: dave180
+1 on the rigid (smooth inside wall) pipe. If it were me I would look for the best and shortest route to go horizontally through an outside wall. I would shy away from trying to do a vent through an eave.


Horizontal would mean going out to the garage (through the insulation/moisture barrier) across the back of the garage and through the exterior wall (which is brick).

Any code problems with this? (Alabama)


I don't know the code for dryer venting. My suggestion was based primarily on the accumulation of lint and dust in the pipe and your ability to clean it out. I would reason that the more bends/vertical runs, etc. you have the more difficult this task would be. If it were my house I go for the shortest route to an outside wall.

 

[AandPDan]

One thing to consider if you choose an eave vent is how is your roof vented?

If you have eave vents for the roof nearby the exhaust could be drawn upward and create a mold/moisture problem on the underside of the roof.

 

[gathermewool]

Have you considered a ventless dryer?

 

[toneydoc]

My parents have their dryer vented into the garage itself and not to the outdoors. The garage can get a little humid that way though but not terrible humid. And on nice days you could open garage door to help vent humidity.

 

[flanso]

I ran a 20 foot metal vent vertically through the attic and roof. But drying times were quite long. I added a booster fan and lint trap in the attic which dramatically shortened drying times.
http://www.amazon.com/Fantech-DBF-Dryer-...ent+booster+fan

 

[stranger706]

Originally Posted By: AandPDan
One thing to consider if you choose an eave vent is how is your roof vented?
If you have eave vents for the roof nearby the exhaust could be drawn upward and create a mold/moisture problem on the underside of the roof.

Yes the eaves are vented. I did not realize the updraft was strong enough to draw the moisture back up.

Originally Posted By: gathermewool
Have you considered a ventless dryer?

No, had to look that one up. Kind of interesting...is that the future of dryers? The dryer I have now is perfectly good...should only be about halfway through its life expectancy. I may consider one when its time to replace.

Originally Posted By: flanso
I ran a 20 foot metal vent vertically through the attic and roof.

I'm really not looking to put another hole in the roof. I could deal with going through the eave but there was a concern of moisture going back into the attic a few posts up.

So its looking like the best option right now is out into the garage and exit through the exterior wall. That would only be 2 turns with a total length around 20 feet.

 

[EA82]

I don't see how the moisture would get in the attic if you go through the eave, most eaves are vented anyways, wouldn't the water get in that way, anyway the drier cap does have a flapper for that purpose. Just follow the shortest route, and make sure if the cap has a screen to remove it, sometimes it can be confused with a fartfan cap.

 

[JetStar]

Additionally, as with any exhaust vent, I try not to fight the prevailing wind. I changed my dryer vent from the south side of the house to the north side and made a significant improvement in flow.

 

[AandPDan]

Originally Posted By: laserred96gt
I don't see how the moisture would get in the attic if you go through the eave, most eaves are vented anyways, wouldn't the water get in that way, anyway the drier cap does have a flapper for that purpose. Just follow the shortest route, and make sure if the cap has a screen to remove it, sometimes it can be confused with a fartfan cap.


As the roof heats up air is drawn into the eave vents. If you have a [censored] fan or dryer vent, that warm moist air is pulled into the attic where it condenses on the underside of the sheathing - mold and rot follow.