A Clothes Drier Exhaust Duct

Home | FAQ | Finishing | Sump Pumps | Foundations


A clothes drier dumps 8 or 9 pounds of vaporized water into a laundry room with every average load—enough moisture to cause damage in most homes. To discharge this exhaust outdoors, you hook up a special clothes-drier vent before you set the drier into its permanent position. Such vents come in kits that consist of a flexible plastic duct, clamps and a hood vent pipe. Make sure you get one the right size to fit your drier’s exhaust outlets, and get a vent pipe to suit the installation you plan.

Driers can be vented through a window , with a 3-inch-long pipe or through a wall, with a 12- inch-long pipe. The method you choose will depend on the design and construction of your house as well as where you put the clothes drier. The window vent is easiest to install. Simply replace one pane of glass with a vent plate bored to hold the pipe. Pre-bored vent plates are available in transparent plastic or in aluminum. However, you can make your own out of a scrap of 1 exterior ply wood and then paint it the same color as the window frame.

If you don't have a convenient window, or if your windows are close to plants that the exhaust would parch, you will need a wall vent. This requires making a large hole through the foundation if it's made of cinder block, or through the siding and header joist if the foundation is poured concrete. Either job is fairly simple with an electric drill.

For efficient venting, the duct should always be as short and straight as possible. Although a plastic duct can bend to snake around pipes or joists, and extra units may be added for stretches of more than the kit’s usual 20 feet, loops and long distances slow down the air flow and may cause the duct to clog with lint.


Installing a Vent in a Window

1 Attaching the vent plate. Chisel out the putty around one pane of glass, pry out the glazing points and remove the pane. Wearing goggles, use a hacksaw to cut the vent plate to fit the window opening. Then, working from outside the house, set the plate into the opening. Anchor the plate with glazing points and seal the edges with glazing compound. Nail the window shut so that it can't be opened accidentally.

To make a plywood vent plate, use the pipe as a template for drawing a circle of the required size on the wood. Cut out the circle with a keyhole saw, then trim the plywood to fit the window opening. Follow the procedures above for removing the glass and installing the wooden plate.

2. Inserting the vent pipe. Slide off the flange plate from the back of a 3-inch-long vent pipe. Working from outside the house, push the pipe through the hole in the vent plate until the back of the hood is flush with the plate.

3. Attaching the duct. From inside the house, slip the flange plate over the back of the pipe and press it firmly against the vent plate. Place a clamp on one end of the duct, then fit the duct over the pipe and anchor it by tightening the clamp. Move the drier to its permanent place and extend the duct to the exhaust outlet on the drier. Use scissors or wire cutters to cut off excess duct. Slide a clamp around the loose end of the duct, slip the duct over the drier exhaust outlet and tighten the clamp.

To prevent the duct from stretching or sagging, anchor it with strings tied to nails in the wall or ceiling joists, or with perforated metal straps held in shape by nuts and bolts and nailed in place.


Installing a Vent in Masonry

Making the opening. Locate the exhaust opening close to the drier but away from pipes and shrubs, and outline it with masking tape, indoors and out, in a circle the same diameter as the vent pipe. Wearing goggles, use a ½-inch masonry bit in an electric drill to bore several holes in the circle from outside, penetrating to the hollow core. Knock out the material between the holes with a cold chisel and hammer. Chip away the edges of the opening until it's large enough for the pipe. Then bore and chisel out the opening on the inside of the block.

2. Sealing the vent pipe. Spread a 1-inch band of mortar around the exterior opening in the cinder block. Slide the interior flange plate off a 12-inch- long vent pipe and spread mortar around the pipe behind the hood. Push the pipe into the opening, pressing the hood in firmly to squeeze out the excess mortar; wipe it off. Working inside the house, clean away any mortar inside the pipe. Spread mortar around the interior opening in the block, then slip the flange onto the pipe and press it on firmly. Wipe up the excess. Attach the duct to the pipe and drier.


Installing a Vent Siding

Cutting the opening. Use the pipe as a template to draw a circle on the siding over the header joist but between the ceiling joists. Then cut the opening through the siding, through the sheathing and through the header joist. As you saw through each layer, remove the material so you can get at the next layer easily. The hole can be cut by drilling a starter hole and using a keyhole saw for wood, or a saber saw with a metal-cutting blade for aluminum or asbestos siding. A circle cutter in a 3/8- or ½-inch electric drill is faster, but practice using it before you try it on the wall.

2. Sealing the pipe. To weatherproof the opening, seal it all around inside and outside with butyl or silicone caulk applied the same way as mortar in a cinder-block installation .

Top of Page | Home | Prev: An Exhaust Fan in a Ceiling | Next: Related Articles

Updated: Sunday, August 14, 2011 16:55