Hired a licensed pro for a shower niche framing job, am I being too picky?

Putting a shower niche on an exterior wall is a massive mistake that most experienced framers or tile guys will steer you away from imediately. When you cut into those studs and push the backer board out toward the exterior sheathing, you're essentially deleting all your insulation in that cavity. In the winter, that niche is going to be freezing, and you’ll likely deal with condensation issues behind the tile that can lead to rot faster than you’d think. This is especally true in colder climates where that R-value is the only thing keeping your wall from becoming a block of ice. The structural aspect sounds even sketchier if he didn't properly support the window header. If he cut out studs to make room for that niche without adding proper king studs and jacks to carry the load of that window, you’re looking at potential sagging or window operation issues down the line. Framing isn't just about making a hole the right size; it's about transferring the weight of the house around that opening. If the header is just hanging there or only supported by the exterior sheathing, that is a major structural failure.

As for the stained wood, framing over nasty black staining without checking for rot is a huge red flag. You need to take a screwdriver and poke that wood yourself. If it's soft or punky, it has to come out. Just beacuse it's a licensed carpenter doesn't mean they aren't cutting corners. If the studs aren't level or plumb now, your tile job is going to be a nightmare. You can't easily fix a significant lean with thinset, and you'll see every imperfection once those grout lines go in.

If I were in your shoes, I’d stop the job right now. It's much cheaper to tear out a few hours of bad framing than it is to tear out a finished shower because the niche is leaking or the wall is bowing. Move the niche to an interior wall where you don't have to worry about insulation, and make sure whoever fixes the framing actualy uses a level and addresses that subfloor rot properly before anything else gets covered up.

I'm just starting to learn about this stuff, and I always thougth 'licensed' meant they had to follow building codes for things like insulation. Is there actually a specific code that bans niches on exterior walls, or is it just a 'best practice' thing? I’m worried becuase I was planning somethig similar for my guest bath next month. If the guy you hired ignored the black staining too, that makes me wonder if 'licensed' even guarantees quality work anymore or if it's just a piece of paper for the city.

The 'licensed' tag is often just a piece of paper for the city; it doesn't mean the guy has a good eye for tile prep. If those studs aren't plumb, you're looking at a nightmare when the tile goes up. You'll end up with massive lippage or needing thick mud beds just to get a flat surface.

Since it's alredy open, grab a 4-foot level and check the plane across the whole wall, not just individual studs. If it's wonky, sister some straight 2x4s to the existing ones to get a perfectly flat plane for your backer board. It’s a cheap fix now, but if you wait, you'll be fighting those walls for the rest of the project.

Honestly, if he didn't even mention using a pre-formed niche insert, that’s another strike. Those foam inserts are way easier to waterproof than custom wood framing. If you stick with the wood frame, make sure he pitched the bottom sill slightly toward the shower floor.

If that bottom plate is dead level or sloped back, you’re just inviting water to sit there and rot out that stained wood he ignored. Since he's allready sloppy with the level, I'd bet money he didn't think about the drainage angle.

Check the blocking around the niche edges. If he didn't add extra 'dead wood' for your backer board to screw into, those corners will flex and crack your grout eventually. You realy need a solid 1.5 inches of stud surface for the board edges to land on so they don't just hang in space.

Regarding that staining, even if the wood is solid, I’d scrub it with a mold killer like Concrobium before closing it up. Trapping spores behind a vapor barrier is asking for trouble if any moisture gets in there. If he was too lazy to clean the plates, I’d bet he skipped the extra blocking too.