This is the 2nd times I see this condition in my inspection. There is a 6" vent from laundry room ceiling to attic. The vent pipe terminate in attic, but not connect exterior.
I have not idea why the interior area ceiling need an vent to attic, the first new construction house builder told me it is because the dryer is gas supply and it need vent for fresh air. Yesterday the laundry room dryer is electrical supply, I have not idea why do we need this vent. I double check the dryer has another directly vent to roof for dryer only.
Look this picture, the left hand side is the vent from laundry room ceiling to attic, the right hand side is the dryer directly vent to roof.
It is likely not an exhaust vent, but rather an intake vent. Typically for the intake of combustion air for gas-burning appliances. Did you notice a pipe hanging in the utility room near the furnace and/or water heater that looked similar to this?
As Ryan said, it’s for intake, not exhaust.
If the gas dryer is running, and the door is closed, it could use up the oxygen in the room, and cause carbon monoxide or back drafting.
In my area, it’s typically just a register vent in the ceiling, pulling air from the attic.
The pass through vent above the door would do the same thing, and also meets code, because it pulls combustion air from the hallway.
It’s likely that the plans for the laundry are the same home to home, and that vent gets installed whether the gas or electric dryer is put in. The builder gets the home to the 95% point and then the buyer chooses appliances and other finish options.
I do understand what you write there. My questions is why not connect to exterior for intake fresh air from outside? As I am not like the attic air quality and it is energy waste connect to attic.
If it is FL building code required it, I will pay attention about it next time.
I agree, it’s not ideal, especially considering fire blocking/ proofing, but in FL it is allowed.
I see it done that way often. The only time I see it ran to the roof /exterior is when there’s a gas water heater in the garage, so they keep the garage fire separation intact.
Search for the current FBC and read about all the requirements pertaining to Mechanical, including ventilation & combustion air for gas appliances. There are options, and it’s quite thorough.
