Babka: ha. they (fixtures) are vented to the space above, (which is under the stairs), not to the outside - which is against the code, I know that much. I guess they (whoever added this bath) ran into the same problem with venting fixtures as we are facing trying to figure how to vent the exhaust fan. and maybe that's why there is no exhaust fan to start with. The bathroom is under the staircase whichi s in the middle of the house, and there is space directly above it because the ceiling is short. But then the ceiling height changes as you go to any neighboring room (the rest of the house around has much higher ceilings). Basically, you can put the duct vertically through the ceiling above the bathroom, but then as you turn it 90 degrees towards in the direction of any outside wall, it would have to come out through the wall of any room around, not in the ceiling above the rooms. And if you try to go higher with the duct so that the turn is at the level of the over-the-ceiling space for these rooms, then the duct would have to come out through the staircase! Hard to explain, but I hope you go the picture. Also, even if we could somehow get the duct to the space over the ceiling of any adjacent wall, then we still can't open up that high ceiling to run the duct further because it has some fancy beams and moldings (house is over 100years old) so we cannot touch the ceiling. That's why I wrote "absolutely no way" for the ceiling route Unless, as somebody above suggested, we place the fan in the ceiling, but run the duct through the wall down to under the house (actually through the under-the-stailrcase part as the stairs go down). But as far as I understand that comment, we will have to install some inline fans in the duct to keep the air moving down...

Think you missed something, Tom. She doesn't want to vent into the attic. She wants to vent OUTSIDE by punching THROUGH a closed section of the soffit. That section of soffit is 4 feet from any vents. FWIW, it is not the optimal solution but it is extremely common where I live because of heavy snow and ice buildup on roofs which can block roof vents; it does meet code, and it is a hell of a lot better than no fan at all or just venting into the attic as so many nimrods do. Our upstairs bath fan is vented out through the soffit because there was nowhere to go in a side wall due to the angle of the roof, going through the roof would have tripled the cost of the installation, and going through the gable end would have made much too long a duct run for the fan we needed to use. (Long story I will not go into here.) Since our house had continuous soffit vents, the vents for several feet in either direction from the outlet were blocked off so the warm, moist air wouldn't rise back into the soffit. There is a special duct outlet made specifically for going through a soffit, it looks like a short (maybe 6" long) cylindrical pipe with a grille at the end. A hole is cut in the soffit, the outlet pushed through from the outside and glued in place. Then the duct is attached to this. One with a screen inside the grille will keep insects from coming in and taking up residence in your attic. Make sure you use insulated duct so you don't get condensation in the duct (and be careful when you open the box with the insulated duct - it's packaged compressed and ours sprang out like those peanut cans with the "snake" inside!).

You can also transition from 4" round to oval, and then back to round where it connects to the outside cap. The oval shape easily fits inside a wall and you can maintain the same cross-sectional area. Even Amazon carries a variety of oval duct and fittings. Below is one example that is used for a dryer, but you could use it with a fan as well. Or you could just get fittings and make up your own to fit your situation. Here is a link that might be useful: Round-to-oval-to-round periscope duct

JDS and Joe don't laugh at my lack of knowledge but explain something to me. We have wooden hexagon shaped attic vents in three gable ends. See link below - mine are similar to this. I need to remodel a bathroom and install an exhaust fan. Can we run the duct work to the exhaust fan out the hex attic vent? I would use the one closest to the bathroom of course. If so, how does the duct attach to the attic vent? I am assuming there are some type of clips or fasteners or thing-a-ma-jiggies that does that. DH and I DO NOT want to go through the roof, but would if absolutely necessary. I had always assumed we would need to go through the roof so this discussion may help solve our problem. Joe don't you dare get sarcastic - just tell me if I am on the right track. I would hire you to do this if you were in Kentucky :). And I wouldn't get three quotes. Hex wooden attic vent