Dryer Vent Through Roof Code

When bath fans and clothes dryers vent through the roof they melt a bunch of snow.

Dryer vent through roof code.

The international residential code allows you to run a dryer vent through the attic but you can t terminate it there. Exhaust ducts shall have a smooth interior finish and shall be constructed of metal a minimum 0 016 inch 0 4 mm thick. Keeping a clean dryer vent is much easier when you can safely reach the exit. Considering that back pressure higher than 6 wci is generally recognized as inefficient you can see that venting through the roof with non dryer specific vents is immediately problematic.

If you have to install bends you should reduce this limit by 5 feet for every 90 degree bend and 2. The roof area of a house is used to vent many of the homes mechanical systems. Exhaust ducts for domestic clothes dryers shall conform to the requirements of sections 504 6 1 through 504 6 7. Flexible duct shall not be concealed within the construction.

The vent should be as straight as possible and the code sets a limit of 25 feet on its length. 504 6 1 material and size. The plumbing stacks are used to vent sewer or waste water odors and allow for proper gravity flow. Dryer vents should always be vented through the side of the house and not vented through the roof and ideally the exit should be fairly close to the ground.

A proper hood or a roof cap equipped with a backdraft damper must be at the termination of dryer venting. These terminals need to be cleaned on a regular basis to prevent lint buildup. Clothes dryers should be vented through the side of the house preferably within reach from the ground. The exhaust duct size shall be 4 inches 102 mm nominal in diameter.

Bathroom and cooking area fans also vent to the roof generally through a gooseneck style vent that exhibits a damper and grill. The laundry is located in the middle of our home in a hall closet. The maximum length of a 4 inch 102 mm diameter exhaust vent shall not exceed 35 feet 7620 mm from the dryer location to wall or roof termination and shall terminate with a full opening exhaust hood. The less back pressure is created by the roof vent the more efficiently the system performs.

When we bought our condo the home inspector said we might have trouble with the dryer vent and he sure was right. Dryer venting cannot be combined with other systems such as chimneys or exhaust vents. Check the local codes and dryer manufacturers recommendations for specifics in your area.