How to vent dryer in 2x4 wall?

I can't see the pic, but you can run a rigid duct up the wall. It doesn't have to be inside the wall. They also make flat box shaped periscope type ones, but that's not made for long lengths. Is this for a regular dryer or stackable?

mikegp said:

I can't see the pic, but you can run a rigid duct up the wall. It doesn't have to be inside the wall. They also make flat box shaped periscope type ones, but that's not made for long lengths. Is this for a regular dryer or stackable?

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This is for a regular electric dryer.

I'm thinking of using this...Link to dryer vent

Those short radius 90s look like trouble to me. Consider 4 PVC drain pipe with long sweep / long radius 90s not glued so it can be disassembled for inspection / cleaning.

Sheetmetal rectangular duct is what has to be used. That means getting a local hvac shop to make it per your spec's.

It does not matter about he link, what matters is the IRC and fire codes.

I would not use that duct from the Home Depot link. Fer a drawing and the dimensions, or rip out that wall in make it a 2x6. Especially if you are putting in plumbing for a washer.

You need to use 4" metal duct. Metal tape on the joints- no screws allowed. The termination must be 3ft from windows and other air intakes.

SeniorSitizen said:

Consider 4 PVC drain pipe with long sweep / long radius 90s not glued so it can be disassembled for inspection / cleaning.

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I believe pvc is strictly prohibited anywhere in the country. Lint sticks to it and it builds a static charge. Plus it doesn't handle burning very well.

I would definetly use metal as was recommended .Would also make sure there is a ground wire attached.I've have three friends places burn even with metal.
Best thing with any is to make sure you have a regular cleaning schedule.
I'm not one of "those kinds of people". Just sean to many things happen from lint buildup and inproper materials and installs.

PVC outlawed many, many years ago... smooth metal is required; pp.7 Exhaust systems- gas or electric; http://www.codecheck.com/cc/ccimages/PDFs/CC6th_Sample.pdf

Even the short periscope is bad. Building a round to rectangular duct will stop more wet lint and create air turbulence; http://www.dryerbox.com/ratings/dryerfittingschart.htm

Will you be adding builders paper to the frame wall, on concrete side, or SPF?

Will you be adding foil-faced foam board to the exterior rim joists? Could you still add a vapor barrier under the frame walls near the concrete perimeter to stop capillary wicking; http://www.greenbuildingadvisor.com...ressure-treated-sill-plates-and-building-code Where are you located?

Gary

TheEplumber said:

You need to use 4" metal duct. Metal tape on the joints- no screws allowed. The termination must be 3ft from windows and other air intakes.

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Actually they now are allowing screws to be used, as long as they do not penetrate anymore then 1/8" into the interior of the dryer duct.

mako1 said:

I would definetly use metal as was recommended .Would also make sure there is a ground wire attached.I've have three friends places burn even with metal.
Best thing with any is to make sure you have a regular cleaning schedule.
I'm not one of "those kinds of people". Just sean to many things happen from lint buildup and inproper materials and installs.

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There is no reason to ground the duct. As for your friends places catching on fire. I doubt that it had anything to do with the dryer vent.

gregzoll said:

Actually they now are allowing screws to be used, as long as they do not penetrate anymore then 1/8" into the interior of the dryer duct.

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They've been allowed for a long time but the pros around my area don't use them.

TheEplumber said:

They've been allowed for a long time but the pros around my area don't use them.

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I do mot like them either. Too much hassle when you have to have a bit of flex, when you have the vent just a bit higher then the length of the duct.

Plus after a while, the scews do not hold as you know.

gregzoll said:

There is no reason to ground the duct. As for your friends places catching on fire. I doubt that it had anything to do with the dryer vent.

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That's wasn't my call.That is what the fire marshall determined as the cause.Grounding will help with the static charge.

Maybe not available in all areas due to local codes: In my area a contractor can go to the local HVAC supply store and buy rectangular sheet metal ducting that goes into a wall before sheet rock is applied. Within my county a homeowner cannot purchase from an HVAC supply house. Plumbing-yes, electrical-yes, but not HVAC, go figure. There is an inlet at the bottom and and outlet at the top which can be moved to either side, not end-to-end. There are NO screws within these purchased units and tabs are provided for installation so that no screws penetrate the duct. I don't know the rating tags that I have seen on these but I do know a UL/FM tag when I see one and they are on there.

Thurman said:

In my area a contractor can go to the local HVAC supply store and buy rectangular sheet metal ducting that goes into a wall before sheet rock is applied.

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I'd like to visit with the person that thought of that plan to determine how he proposed cleaning it.

mako1 said:

That's wasn't my call.That is what the fire marshall determined as the cause.Grounding will help with the static charge.

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What Fire Marshall. Not a requirement in Springfield. The duct is already grounded when connected to the dryer, unless the exhaust outlet is plastic. There is no static charge in the metal duct. Also how did they state to ground it, since it would have to be grounded with a complete path back to the incoming Cold Water pipe if Copper out to the curb, or to the Earth Ground Ufer or Rod.

The dryer itself is grounded through the 4 Prong plug. Attaching a ground wire, would require a screw, which will catch any lint that gets past the screen.

Dryer fires are caused by a build up of Lint inside the dryer and in the pipe if not cleaned out on a regular basis.

Gregzoll: Not going to get into a pissing match with you as you know more than us all for sure.Simply stating that the fire marshall in my little Podunk town stated the fires were caused by dryer vent fires .I don't have a clue what caused them.The town is not Springfield but Mattoon.You can look up the fire that caused Burnham Neils death if you wish.Owner of Neil Tires,
I have never seen a dryer with a 4 prong plug.It's true that a dryer would be grounded by it's duct thru the machine .It's also true that lint going thru the pipe will build up a static charge that can be disapated by a ground wire.Never said it was code or stated by any official .Just a good idea IMHO.

New dryer circuit installs have been required to be 4 wire since the 70s. Older 3 wire circuits can be reused with new dryers.