Have not seen this before

From today’s inspection. 2 story residence, built in 1997, both the Master bath and Hallway bath exhaust vent hoses terminate into the attic floor structure. As you can see, hose is foamed in place, the only exterior vent ports are the dryer and microwave. New one on me, can someone explain?


Check to see if it has a central fan unit down in the furnace room. Quite common in our area. Usually its piped in with solid tin ducting though? It typically vents out the side of the home down around the sill plate.

The foam may have been for airsealing purposes or possibly just to hold the hose in place.(They don’t use screws and brackets / metal strapping there??)

Of course, the bath fans must go to the exterior. (and not just out into the eaves with perforated soffit but fully to the exterior through a vent hood.)

Should be to the exterior.

I think you are missing my point. I realize the foam was there to hold the hose in place and to provide a barrier. I realize they need to be exhausted to the exterior. Can anyone explain the building principal of running the hoses into the interior cavity of the home with NO means of exit and how could this EVER be an acceptable practice. That is my point.

Thought the flex duct was coming up from the wall and into the insulation on the attic floor.

Then Darrell’s post #2 probably hit it right on…or were they planning on some central exhaust fan that never got installed?

The duct is undoubtedly going to the soffit.

I don’t think it can be explained, because I don’t believe it is an acceptable practice.

I would also be incline to believe that this was a “homeowner” installation, rather than part of the original build.

I would comment in the report that “the vent terminations were not visible and should be verified as venting to the exterior of the residence, or proper venting should be established by a qualified contractor.”

My guess is with Joe. Just turn on the fan and listen for it outside.

Common around here. Stupid install. BTW: The bathroom exhaust pipe should be insulated.

Hope this helps;

This is what I typically see that happens when you vent an exhaust fan out an soffit vent. The one pictured may have even missed the soffit opening.

There are a few problems that I see with installing out a soffit.

  1. reduced insulation
  2. Stained sheathing

It make more sense to vent towards a exhaust roof vent and not an intake roof vent like a soffit.

I do have an illustration that states it can be vented out a soffit. See attached


I disagree for this reason: anywhere you penetrate your roof, you are more likely to have a leak. Punching holes in my roof would not be an option. My personal preference would be to vent to a soffit using an approved soffit vent (there would be no stained sheathing in that case). The insulation loss is negligible.

Time for another Global Warming summit!

I did not say punch a hole in the roof, in most cause a vent opening is already there. I stated direct towards an exhaust roof vent like a ridge or roof top.

I disagree with your disagreement.

Your illustration showed a dedicated roof bathroom vent. I misunderstood your position. Sorry.

Dave what do you mean by reduced insulation.
The soffit vent is an opening that would get covered up and actually cause a little less ventilation,yes?

No reason to be sorry. I value your opinions.

Come to find out that the homeowner was the GC and this is not the only substandard issue with this home.

I inspect homes in the same general area you do and I have never seen this before, but agreed that it is a “stupid install”

Thanks for the feedback.

Bob, I probably mis spoke about the vent pipe reducing the insulation amount, not a big deal. I just am not a big fan of venting the exhaust fan out a soffit vent, but what the heck do I know!!

I know I do see quite a few of the soffit exhaust vent termiations stained and blocked like the one pictured.