If drilling a hole through the stone wall not under a soffit (as at an end of the structure) isn't possible, I'd go through the roof. Putting a properly flashed and sealed vent into a tile roof shouldn't be too difficult for a capable roofer, though it's a small project for sure.

@Elmer J Fudd Every wall occurs where a soffit is, unfortunately. The house is made of hip roofs, so there are no gables to create that condition.

Well then, if it were mine, that suggests through the roof to be the most likely good solution.

Or, if the local code permits, how about replacing 15-20 feet or so of vented soffit cover with solid cover that you seal closed at each piece's edges and put a soffit outlet in the middle of that stretch? Choose the side carefully considering prevailing winds so that the output isn't blown back into the attic through an open section. .

@Elmer J Fudd This project is a renovation, so I dont have any real control over which wall this vent will go onto, prioritizing the least amount of bends in the duct. Hmph. I have a feeling it will be near impossible to coordinate a tile roofer's schedule with the renovation.

If it's been blowing into the attic for a long while, can't it wait a bit longer until a roofer can drive up? I'm not sure that timing is that critical.

The difference between one wall and another is 90 degrees, shouldn't be a big deal. But heck, I'm just a homeowner. I always try to have things done the right way, compromises or less advisable alternatives too often lead to further problems.

@Elmer J Fudd I also am a homeowner who only wants things to be done right.. that's actually part of my problem, because it might be to a fault! I know venting this through the roof is the most correct, and most expensive option by a long shot. Just trying to strike a balance..

Currently this bathroom has no shower, so this fan is never turned on. But all of that will change with the planned renovation. I think the best thing i can do is have them price it and see..

Most any competent contractor can do the roof work. There is nothing really special about tile.

Okay. I will push for roof exhaust. The contractor we last spoke to (didn't hire anyone yet) said it was common for it to go out the wall, and I was trying to be sure I wasn't crazy thinking that was incorrect.

@mike_home Yes thank you!! This was the info I was getting at when I asked about coordination. Gold star for you

Are you in an area where tile roofs are common? My area has only a few older houses with clay roof tiles and it is quite difficult to find a residential contractor to work on that type of roof. If you get someone who isn't familiar with tile, they can end up cracking tiles and then you have a new set of issues if matching replacements are not available.

That's why I was originally thinking I would need a specialized roofer.

We do have lots of old homes in the area, and many of them have tile roofs. Its just that I'm afraid hiring a tile roofer to do this will add thousands to this project just in this fan. But it sounds like that's what must be done.,,

"The contractor we last spoke to (didn't hire anyone yet) said it was common for it to go out the wall,"

If he does this regularly under soffit vents, he's lazy and not committed to doing things right. That gives you a good reason to hire someone else, no telling what other shortcuts are "common" for him.

Mount it to vent out the soffit. You are using mechanical venting which will easily bypass the passive venting in your soffit. Save your money on the roof work and buy a quality bath fan, you'll have no problems if you buy the right equipment.

https://www.lambro.net/product/4-white-plastic-eave-vent/

"Most any competent contractor can do the roof work. There is nothing really special about tile."

That depends on the age and condition of the tile and the experience of the roofer. The last thing you want is a production asphalt shingler traipsing about on brittle old tile. This has the potential to become a nightmare; venting through a soffit does not.

Shoot.. This thread is starting to look like my research.. Some say it's OK and others no.. I have had someone screw up my tiles before, and they crack each year just from the weather. I can't truly accept that tile isn't it's own animal in that regard.. And I've read that there is a special way to even walk on them so you don't break them.

I just don't want to have to deal with a mold problem later because I cut a corner but also don't want to spend thousands if another way is acceptable due to new products or technology advances or whatever it may be..

Another concern with a tile roof is whether replacement tiles are even available. Even though the same company was still making the same shape, the current version of green doesn't match the green with gold flake glaze of the vintage tiles. Took three tries to get a reasonably close match glaze and then we hid the replacements on the back side of the house. Walking up the tiles isn't all that difficult but it takes a nimble person with soft soled shoes, the lighter the better.
I would not mess with a tile roof if the soffit vent would work.