We have a two storey condominium. Upper unit bathrooms and dryer exhaust vents are located in the soffits. we have not seen any indication of moisture in the attics, but we are re-shingling the roof and wonder if we should be putting vent sleeves in the soffit and routing these exhaust ducts to the roof. These exhaust ducts also have long runs of flexible duct. We feel it may be more efficient to vent out the roof than to force hot air down below the soffit. Any comments or suggestions would be appreciated

 

Bath exhaust should be vented to gable ends of a roof only if you have them.

Short of that, bath fans should be located in interior soffits in the bath ceiling so that the exhaust can be directed directly out thru an exterior wall.

It is not a good idea to vent bath exhausts (and may very well be against your building code) to vent bath vents to the eaves/soffits of a roof structure or thru the roof itself.

The main objection to venting to eaves is that open eaves draw air in and upward to vent thru the ridge of the roof. The result is to have moist bath air sucked right back into the attic where it will condense upon the underside of the roof sheathing. The result is condensed water and mold and mildew growth.

Venting thru the roof directly can cause condensation to form within the duct itself and cause the water to flow back into the fan. Also not a good solution.

Professional HVAC installers suggest running the ducts to the end of a gable only of thru a wall even if it means having to build a soffit in the bath ceiling to accomodate the duct.

Long horizontal runs to an exposed gable end should be assisted with power venting.

You should avoid roof venting and eave venting altogether.

 

Thanks for your input. Unfortunately I only have two choices. The bathroom exhaust fan currently discharges via a 20ft flexible insulated duct through the attic to the soffits. The only other alternative is to put in a vent sleeve at the soffit which will then discharge the exhaust through the roof level above the soffit. On balance I thought this was a better alternative

 

Personally, it doesn't appear you are comprehending the code nor itsproper applications and possibilites for running the duct to an outside wall of the house or thru the gable end of an attic, but it is your house and your decision and your property in which to violate the building codes and to deal with your failures accordingly.

If "I" have failed in my explanations please tell me so I correct them.

But as of now I only see a failure to comply.

Whatever.

 

Its all in what you need are can do. As long as the vent pipes vent to the outside and not in the attic it will pass. Many companys have vent grills just for this so the vent pipe vents to the outside there ,not in the soffits.


ED