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Doing a dryer duct, the right way...

3215 Views 7 Replies 3 Participants Last post by  Gary in WA
I am upgrading the duct on my dryer from a 3" diameter plastic duct to a 4" rigid galvanized steel duct.

Current configuration:
Dryer is located in an unheated basement on an exterior wall.
The plastic 3" duct makes a 90 degree turn "vertical" at the dryer. Runs about 8 ft then another 90 degree turn "horizontal" and attaches to a metal duct/hood with flapper. The duct/hood assembly runs through the rim joist and brick fascia.

Steps I have taken:
I enlarged the hole in the brick fascia and rim joist to 4-1/4". I used a carbide hole saw so it is a very smooth cut.
I bought Heartland 21000 dryer vent closure and painted it to match the exterior brick color.
I bought a few sections of 4" rigid galvanized steel duct, the kind that comes in un-rolled 4ft sections. Also bought two non-adjustable 90 degree galvanized duct pieces. There is not a lot of horizontal duct work, but I will keep the seams facing upward.

Where I need some guidance:

Assembling the duct sections..... Is UL approved metal tape the best product I can use? What about mastic reinforced with fiberglass mesh? I hear clamps can pinch things and screws collect lint. Any product links would be quite helpful.

Attaching the duct sections to cinder block wall.... I guess some type of pipe strap, again a link would be helpful.

The gap between the duct work and the brick fascia + rim joist..... Do I cement the duct into the brick fascia and fill the void in the rim joist with some sort of heat safe insulation?

Designing the duct in a way that it is easily cleanable.... Got nothing on this one.

Designing the duct it so it can be attached and removed from dryer easily.... Should I put a small piece of aluminum flex duct between the dryer and the rigid duct?
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I'd take back the termination hood you bought and get a Type "A" with 50% less air-flow restriction:

PS. make 45* bends rather than 90's. If not possible those 90's are ok with that short of ducting.
Try out the termination hood and let us know. It appears to be a good design, don't know how air-tight with the little nibs to keep the plastic door from freezing shut on the metal housing...

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