Clothes dryer vent outlet routing

[Dan C]

Hello all,

I'm having a new house built, and today I noticed something that I wanted some opinions on...

My laundry room is not on an exterior wall of the house, so when they installed the dryer vent, it is run straight up and through the roof. It is the rigid (smooth) aluminum material, not expandable "accordian" hose.

Is having the vent run straight up from the dryer a problem? I've never seen that done before. Any "backpressure" issues from this? My thoughts are that hot air rises, so would probably be a good thing. True? Is this the normal way of doing it? Thanks for any info you can provide.

[Noozer]

Just make sure that they give you some method of accessing the bottom to clean the lint/etc. out of it. Most likely they'll just tell you to pull the dryer out and reach in with your hand.

Of course a vertical vent will be easier to clean than a horizontal one.

[Robert Allison]

The only problem that I have seen with these is that the roof tends to get covered with lint. It is unsightly, but hardly a problem otherwise. A good rain storm cleans it, that or a water hose.

[JerryMouse]

Look at it like this: What choice do you have?

[Joseph Meehan]

It sounds like they did a good job. Rigid metal (not the accordion stuff) is far better, more efficient and safer. Up is good, It is warm air going up, it will actually travel easier up, like a chimney, although not all that much.

Cleaning is a possible issue, but I suspect just pulling the dryer out. You really wanted to clean under it and maybe remove the back and clean inside anyway. That straight smooth bore run will be far easier to clean than most situations are.

[royroy]

My son called me to help with endless running dryer problems in his new (to him) house. It had a similar installation, which I blew though, from the bottom, with an electric leaf blower. Disconnected the "plumbing" from the actual roof vent and blew into a gunny sack. Anyhow, the problem was the roof vent. Contractor used the typical vent used to vent hot air from an attic. It had screen with a mesh so fine that all the lint collected there. It was jammed. I tore out the screen and we're going to see how that works. If it doesn't, will look for a proper vent for such an installation. I'm sure there must be one.

[Burnt Eddy]

Depending on how observent your building inspector is... a dryer vent has a length limit of 14' (horizontal and vertical) and two 90 degree elbows. You have to deduct 2' of length for every additional elbow (per the Building Code, ICC). If it is longer, your appliance dealer may be able to help with a booster fan or something else....

[Brian O]

I have a stack type dryer vent. They are not that easy to clean properly. First of all, of course, you need to be able and confident about walking on the roof of your house. Not the most pleasant thing in the world to do. Secondly, to clean it properly requires a special brush with a long handle. They sell these at various stores. Thirdly, a big problem is birds. For some reason they like the warm air, and for whatever reason they tend to fall down the stack. Cant tell you how many birds I've retrieved out of my dryer stack at the base. Unfortunately for them, they dried out before I realized they were there. Not only is it sort of disgusting, but it can be a fire hazard as well if they get too dry. You need some sort of cover on the stack to keep them out. Chicken wire comes to mind. Don't use window screen, as that will collect lint and clog the stack. I don't recall having a lint problem on the roof. Maybe some folks wear more cotton than others. Anyway, that's my experience. I'm in the process of rerouting my dryer vent to a side wall. Brian

[Joseph Meehan]

Not a good idea to use that vent. There is a proper vent that has a grill to prevent birds from entering but more important has a flap type valve to close the vent to prevent cold air from entering when it is not operating.

The brush I have can be used from the dryer end. I find that a little work with it and a blower of some type, I have used both a shop vac and a leaf blower does the job along with the brush.

[Duane Bozarth]

Joseph Meehan wrote: ...

...

I've never seen one (the flapper part) that would work well for vertical application, however.

[Dan C]

Thanks (to you and to everyone else) for the info. Sounds like one less thing I need to worry about. Appreciate it!

[Joseph Meehan]

I really don't know as I have no experience with that set up, all mine have been out the side.

[modervador]

vertical

I've seen this used succesfully in vertical runs (as long as the flow goes up):

Deflecto BD04 Draft Blocker

%mod

[Brian O]

"> > I have a stack type dryer vent. They are not that easy to clean

I might try that if I had access to some sort of large volume moving air blower.' B

[Goedjn]

Look at a tractor, sometime.

[Kathy]

Wouldn't exhaust have more pressure than a dryer?

[royroy]

I was going to have to do this sooner or later anyway, so I Googled: "dryer vent" vertical cap There are all kinds. Here's one:

[manhattan42]

ICC International Residential Code for 2003 states:

"M1501.3 Length Limitation. The maximum length of a clothes drye exhaust duct shall not exceed 25 feet from the dryer location to th wall or roof termination. The maximum length of the duct shall b reduced 2.5 feet for each 45-degree bend and 5 feet for each 90-degre bend. The maximum length of the exhaust duct does not include th transition duct."

Exceptions are the use of a mechanical booster or a dryer that can b shown by the manufacturer to be able exceed the 25 foot limits.

A roof vent should be the very last choice for venting a dryer and th vent would best be run to a sidewall via a soffit, or thru a basemen or crawlspace

-- manhattan4

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[Dan C]

Assuming the duct length is well within the limits you described, why do you say that the roof vent is the last choice? Is there something fundamentally wrong with that method?

[Goedjn]

Yes, but it doesn't matter, the flapper is counterweighted.