How to Replace a Dryer Vent – Part 1

This project explains how to replace a dryer vent in an exterior wall. The dryer vent was 10 years old and the louvers were sticking open. The vent is an older style without a bird guard.

Worn Out Dryer Vent

How to Replace a Dryer Vent

I purchased a new deflect-o® 4″ Supurr Guard® Vent Hood with Pipe & Collar, model #GVHXW4 at Home Depot for $10.97 as shown:

deflect-o® 4″ Dryer Vent Model #GVHXW4


The new dryer vent consists of the preassembled vent and pipe, pipe collar (white plastic ring) and bird guard:

deflect-o 4-inch Supurr Guard® Dryer Vent #GVHXW4


The new unit has two louvers compared to three louvers in the old unit. Two louvers are slightly heavier and less likely to stick open. The louvers only allow air flow one-way and prevent back drafts.

Disconnect the Dryer Vent Flexible Duct

Before removing the outside vent hood, I checked the dryer vent duct in the basement crawlspace to see what I was getting into. The washer and dryer are on the first floor and the flexible aluminum dryer duct runs below the floor joists, suspended every several feet by metal hanger straps.

There are two vents through the outside wall: 1) 3-inch bathroom ventilation fan duct and 2) the 4-inch dryer duct. The house sits on a hillside and the concrete foundation walls step down with the exterior grade.

Dryer Vent Flexible Metal Duct in Crawlspace

Dryer Vent Flexible Metal Duct in Crawlspace


A couple of observations about the dryer vent duct:

  • The dryer duct is flexible aluminum.
    This is required by the Building Code and extremely important to handle the hot dryer gases and avoid fires.
  • The duct is properly sized at 4-inches in diameter.
  • The duct is not touching the PVC plastic drain pipes, which could melt the pipe.

From the basement floor, things look OK.

I went up the ladder to unfasten the flexible duct from the dryer vent. However, I saw daylight as I pushed the fiberglass insulation aside to expose the end of the duct! The insulation is a bit darkened from lint as the insulation filtered dryer gases leaking at the loose joint.

Dryer Vent Flexible Duct is Coming Loose from the Vent


Wow! The goober who installed the dryer vent tried to caulk the metal duct to the vent! Silicone caulk has just about no bonding strength and the duct was held in place against the vent only by it’s own rigidity. This is a bad installation! I was fortunate there was no signs of rot on the oriented strand board (OSB) wall sheathing or 2×4 studs from condensation from the leaking dryer exhaust gases. Aside: I have an electric dryer; had this been a natural gas dryer then carbon monoxide poisoning from natural gas combustion products would have been a worry.

Flexible Metal Duct Caulked to Dryer Vent


To get a clean end free of the gummed up caulk, I cut off about 3 inches of the flexible duct with a utility knife, slicing between the spiral metal ribs. When I’d made a complete circle with the knife, the metal rib was cut with pair of wire snips.

Cutting Away the Caulked End of the Dryer Duct


I inspected the flexible dryer duct with a flashlight and found only a light layer of lint inside the pipe. This is well as it appears the clothes dryer lint filter is doing a good job keeping lint out of the ductwork. I vacuumed the lint from the inside of the duct as a far as the vacuum cleaner hose would reach.

The new deflect-o dryer vent was test fitted to work out the kinks in the flexible duct. Ultimately, the 11-inch rigid vent pipe will slide several inches into the flexible duct.

Fitting Metal Duct to Dryer Vent

Fitting Metal Duct to Dryer Vent


Before going outside to remove the old dryer vent from the wall, I needed to find the appropriate mounting screws. I decided that Grip-Rite® 2″ PRIMEGUARD TEN exterior would screws would be best based on what I had on hand in my workshop. The bugle head wood screw fit the recesses in the vent face well and 2-inches is sufficient to reach through the stucco to the OSB sheathing.

2-Inch Exterior Wood Screws for Dryer Vent Mounting


This project is continued in Part 2.

Thanks for reading,

Bob Jackson

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One Response to How to Replace a Dryer Vent – Part 1

  1. Gerald Vonberger October 16, 2014 at 4:32 pm #

    I’m glad you outlined these steps. I had no idea how to get all the way through the wall without ruining the dryer duct or the wall. I’ve never tried dryer duct replacement before, so this is really helpful. If don’t succeed though, I’ll probably just end up calling a dry duct replacement professional.

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