Dryer duct venting

**Steve C.** · 07-21-2011, 07:47 AM

Is it o.k. to terminate your dryer duct through a foundation vent? Only other option in this particular case would be through the foundation wall. I see it done this way quite often, but wanted to see from others what they thought. I can't find anywhere where it says you can't. May not be the "correct" way, but is it something worthy of writing up? Thanks in advance.
Steve

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**Gunnar Alquist** · 07-21-2011, 09:09 AM

Originally Posted by Steve C.

Is it o.k. to terminate your dryer duct through a foundation vent? Only other option in this particular case would be through the foundation wall. I see it done this way quite often, but wanted to see from others what they thought. I can't find anywhere where it says you can't. May not be the "correct" way, but is it something worthy of writing up? Thanks in advance.
Steve

Steve,

The duct should extend to the exterior and should not be screened. Generally, the foundation vent screen will collect lint. If it exits completely at the exterior without obstruction, it should be ok.

**Steve C.** · 07-21-2011, 09:46 AM

Originally Posted by Gunnar Alquist

Steve,

The duct should extend to the exterior and should not be screened. Generally, the foundation vent screen will collect lint. If it exits completely at the exterior without obstruction, it should be ok.

What I meant is to exit the duct through the foundation vent and put the appropriate louvered cap on the end. Just use the foundation vent as a means to port it out of the crawlspace without drilling through a foundation wall.
Steve

**Bruce Ramsey** · 07-21-2011, 10:21 AM

The dryer duct reduces the net free area of the foundation vent. If the net free area falls below the 1:150 rule for the ventilatied space, then it is a ventilation issue for the space.

**Steve C.** · 07-21-2011, 10:30 AM

Originally Posted by Bruce Ramsey

The dryer duct reduces the net free area of the foundation vent. If the net free area falls below the 1:150 rule for the ventilatied space, then it is a ventilation issue for the space.

what are your thoughts on insulating a rigid metal dryer duct that is exposed in the crawlspace. Don't ever see it on an exposed dryer duct, but that doesn't mean condensation won't collect inside the pipe and lint sticking to it and clogging over time. Thoughts? Do you ever call it out? thanks in advance
Steve

**Brandon Whitmore** · 07-21-2011, 02:20 PM

I don't make an issue out of it when a duct runs through a foundation vent, unless there is minimal ventilation present. Just make sure there are no gaps in the screening.

I've never seen anyone insulate a dryer duct, but it couldn't hurt.

**Jerry Peck** · 07-21-2011, 05:06 PM

Originally Posted by Brandon Whitmore

I've never seen anyone insulate a dryer duct, but it couldn't hurt.

The dryer duct may overheat if insulated. Wouldn't want it too close to combustible material in that case, and then the lint inside would be closer to catching on fire by itself. Just some reasons off the top of my head not to insulate a dryer vent.

**John Kogel** · 07-22-2011, 08:46 AM

Originally Posted by Jerry Peck

The dryer duct may overheat if insulated. Wouldn't want it too close to combustible material in that case, and then the lint inside would be closer to catching on fire by itself. Just some reasons off the top of my head not to insulate a dryer vent.

Who needs insulation when you've got lint?

Better not to wrap them. Keep the pipes visible for their 10 year inspection.

Seriously, they will rust out if they are wrapped and leaking. Note the rusty elbow.