View Full Version : dryer vent

Jeff Eastman
04-13-2007, 08:58 PM

Tim Moreira
04-13-2007, 10:20 PM

Your over you limit on length here, not to mention the downward sloped part.

03 IRC:

M1501.3 Length limitation.
The maximum length of a clothes dryer exhaust duct shall not exceed 25 feet (7620 mm) from the dryer location to the wall or roof termination. The maximum length of the duct shall be reduced 2.5 feet (762 mm) for each 45-degree (0.79 rad) bend and 5 feet (1524 mm) for each 90-degree (1.6 rad) bend. The maximum length of the exhaust duct does not include the transition duct.

I count 26 feet with two 90's which would reduce your total length to 16 feet.

Jerry Peck
04-14-2007, 09:56 AM
Yep. Built an addition, relocated the dryer, and instead of taking it right up and out through the roof, they doubled back to the original dryer exhaust.

Real smart, real smart.

P.S., I like that plastic covered slinky too.

Rick Hurst
05-24-2007, 12:26 PM
There is always talk about the height or the length of a run for a dryer vent, but is there a dryer vent minimum height from a surface.

Had one this morning that was so low that the concrete patio was soaked directly below the vent.

It was located near a door and I was thinking during the colder months that this moisture could freeze and provide a hazard.

Any thoughts.

Rick Cantrell
05-24-2007, 12:35 PM
From the 2006 IRC

R303.4.2 Exhaust openings. Outside exhaust openings
shall be located so as not to create a nuisance. Exhaust air
shall not be directed onto walkways.

Rick Hurst
05-24-2007, 01:38 PM
Thanks Rick C. for that really quick reference.

Jack Feldmann
05-24-2007, 02:35 PM
I inspected a one year old condo yesterday that had an interesting installation.

It seems the dryer vent just exhausted into the attic at first. The builder then extended it to the outside. It goes up 10' or so then turns and runs another 20 feet or so. That didn't work so well, so they installed a dryer booster fan.

There's only a couple things wrong with that installation:
1. They attached the bracket to the roof truss - OK so far.
2. But failed to attach the fan to the bracket. It was close, only about an inch away.
3. They wired it to the forced air unit in the attic. They actually wired it to the "other" side of the switch, so if you trun off the switch to service the forced air unit, it will cut ff power to the fan.
4. The forced air unit is on it's own 15 amp/120V breaker.
5. One last thing - The fan doesn't work even though it has power going to it.

Got to love it