How About Dryer Venting into the Attic? - Answers & Solutions  

How About Dryer Venting into the Attic?

It takes much effort, talent, and time to vent your dry outside via a wall in your home. Since hot air always seems to end up in the ceiling, is it safe to have the vents lead up into the attic?

Dryers must not have their vents directed upwards into an attic, as per the International Residential Code. Dryer vents are allowed to pass through an attic, but they cannot be finished there. Venting into the attic poses not only a fire risk but also a moisture problem that can lead to the growth of mould and rot.

Dryer vents are subject to extensive regulations that must be met for your family’s safety and the continued validity of your homeowner’s insurance.

In this piece, I’ll discuss:

Venting into an unfinished attic might be dangerous.
If you want to avoid potential danger, you should use a roof vent.
Exhaust ventilation via roof installation instructions

6 The Risks of Dryer Venting into an Unfinished Attic

Dryers, whether electric or gas, share the same attic venting concerns:

1. The Duct’s Total Length

The distance between the laundry room and the storage area in the attic could be a serious problem. Most dryers have a 35-foot maximum ducting length, according to the manufacturer. When you use longer ducting, it puts a lot of stress on your dryer, reducing its efficiency and shortening its lifespan.

2. Properly Directed

Dryer performance will suffer if exhaust is forced to take circuitous routes before being released into the open air. Bends in ducting at 90 degrees add five feet to the total run.

3. Condensation

Condensation contributes to why the ducting is kept short. Due to the colder temperatures seen in attics during the winter, any moisture present on the interior of the metal duct will condense before it is expelled from the building. The water will collect and return in streams to the back of your dryer.

4. The Accumulation of Fluff

Lint can get stuck in the middle of the duct when water condensate drips down from the top. There will still be a fire threat if the lint finds its way into the attic and accumulates.

Some forms of venting, such as running ductwork farther than 35 feet or into an attic, are prohibited by local building standards. If you’re unsure of what kinds of ductwork are allowed in your area, check the relevant building codes.

6. Placing a Nest for Mice and Rats

When venting into the attic, it is common practise to leave the pipe or duct open to maximise airflow and reduce the risk of clogs. The balls of lint that accumulate around the vent provide ideal nesting material, and the resulting environment is ideal for rats.

Rooftop Dryer Venting

It’s not ideal, but cutting a hole in your roof to let in air can be necessary in some situations. Dryer exhaust can be safely and efficiently vented through roof vents in places where no windows nor exterior walls are present.


For reasons of efficiency and conformity with construction rules, access to the exterior may be best gained via the roof.
More water vapour will condense outside than against the ducting walls if the duct is short and straight, which is why condensation is important.
Be More Thoughtful If you live in a densely populated area, the hum of your equipment and the lingering odour of its exhaust may annoy your neighbours. The airflow from a roof vent will be directed upward and out of sight of any nearby residents.
Prevents A roof vent is less likely to have exhaust blown back into the duct by directed winds.
Safer, since it prevents the growth of harmful moulds and wood rot caused by the buildup of gases in the attic. Gases that are harmful to humans and animals are kept outside, and lint balls in the attic are avoided.


Damaged Roof – If you make a hole in your roof, water will be able to go inside. No matter how thoroughly you try to seal the vent, it will never be as effective as a solid roof.
Aesthetics Depending on the location of the chimney’s exit hole, you may not like the way it looks protruding through your roof. It also may not comply with the roofing codes enforced by your city or county.
Exhaust piping must be at least 12 inches above the roof’s peak to comply with most local ordinances. This not only draws more attention to the chimney cap but also provides additional area for storms to damage.
Installing a duct through your roof is more expensive and difficult because you have to repair the leak and try to restore the roof’s waterproof integrity. To protect your home’s curb appeal, you may require a custom-made chimney crown.
Repair – A vertical dryer vent through the roof may be allowed by your local codes, but only with certain restrictions. Every year, have a professional vent cleaner inspect and maybe clean the roof vent.

Techniques for Dryer Roof Venting

It is easy to over-complicate the task of installing a dryer vent in your roof; you want to make it look neat and avoid destroying your insulation.

Drilling a hole through your roof to install a vent should be simple, which it is if you follow these steps:

  1. Mark up – It is worth spending time planning where the hole is going to come through. Consider, will the duct need to be longer than 35 feet? Will it hit a support beam? Is there another object on the roof that will be in the way of the vent?
  2. Plan the duct path. For the best airflow, you want to try to run the duct with the least number of turns from the back of the dryer to the roof vent.
  3. When you are happy with the placement, cut a hole for the shape and size of ducting you are using. For tiled roofs, remove the tiles from around where you want the vent to sit on your roof.
  4. Cut a hole through the roof insulation with a utility knife and use a jigsaw to cut a duct-sized hole through the support board. If you have tiles cut them so that they fit around the hole.
  5. Raise the shingles so that you can slide the vent cap beneath them. Use scrap wood to hold it out the way.
  6. Spread roofing tar between the vent shield and the roofing deck. Put the pipe of your vent cap through the hole you made.
  7. You may want to secure it with nails, then spread more tar over the shielding and the roof.
  8. You want to have the shingles or tiles overlap the vent’s shielding for better rain flow.
  9. Go back into your attic and secure the duct to the vent pipe. You may want to use a hose clip to tighten the connection.
  10. A cold pipe will condense the water vapor to the inside of the duct before it reaches the outside air. Consider lagging the metal duct pipe to reduce the action of the cold air in your attic on the water vapor.

Do I think I made every point?

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