How to seal dryer vent pipes: Small, medium and large gap filling

• How to seal a dryer vent pipe: Tips for successful renovations
• How to seal a dryer vent pipe: Small gaps
• How to seal a dryer vent pipe: Medium to large gaps

Protecting your home is an important part of any renovation. This is especially true when doing a laundry renovation.

Before gutting your laundry room, consider the placement of the washer and dryer units. It’s important to have the shortest distance possible between the dryer and the exterior vent opening. The longer the pipe, the harder it is to push excess lint out. This can lead to lint buildups and clogs.

The duct type is also an important choice. Old metal foil ducts tend to collect lint and can become a fire hazard. We recommend replacing them with semi-rigid or a smooth-rigid duct system.

Filling the gap between the vent pipe and the wall is also an important step. Proper sealing keeps out pests, dirt and drafts. 

Here’s how to seal a dryer vent pipe.

1. Clean the surface, make sure all dirt and dust is removed.
2. Cut the application tip according to the desired bead size. Load the caulk gun and puncture the cartridge.
3. Apply the sealant by forcing the bead into the gap between the pipe and the wall. Move around the pipe until the perimeter is covered.
4. Tool the perimeter if necessary.
5. Leave to cure. 

For filling larger vent gaps, foam is the best choice. For extra-large gaps up to 3 inches in size, go with Loctite Tite Foam Big Gaps Insulating Foam Sealant. To achieve the best results, the foam should be applied in several layers, especially for vertical joints. Both of these sealants form air and watertight seals that protect against the elements. They can be used indoors and outdoors and are paintable.

Here’s how to seal a dryer vent pipe, from the exterior.

1. Clean the surface, make sure all dirt and dust is removed.
   
2. Shake the can vigorously for at least 30 seconds (minimum of 15-20 times).
3. Pull the safety tab to activate the trigger.
4. Hold the can upside down and squeeze the trigger to dispense foam into the gap.
5. Fill the joint in several layers by applying smaller foam strings up to 1-inch thickness.
6. Accelerate the cure time by applying a slight water mist.
   
7. Cut away excess foam after an hour.
8. Wait 24 hours for full cure.
9. Cover the foam with paint, plaster or mortar to protect from UV rays.
10. Clean tools and uncured foam immediately with acetone.
11. Attach a vent hood over the vent opening.