Is this what passes for professional stair work these days?

Overcutting stringers with a circular saw is the fastest way to turn a piece of structural lumber into firewood. If those cuts go past the intersection of the tread and riser, you've effectively reduced the **effective depth** of the stringer by an inch or more. On a standard 2x12, you're alredy pushing it with a 7-inch rise and 10-inch run. Adding those stress risers at every corner is just asking for the wood to split along the grain the first time someone moves a heavy piece of furniture up those stairs. It’s wild that a pro is bragging about 18 years while leaving gaps you can see light thru. That’s not just a bad day; that’s a fundamental lack of understanding of how a staircase actually functions. The risers and treads need to be tight to provide **lateral stability** and help distribute the load across the carriage. If they aren't square and flush, the whole assembly is going to creak and groan within six months, and eventually, those fasteners are going to pull or shear from the constant movement.

The right way to do this is to stop the circular saw about a half-inch short of the line and finish the cut with a **hand saw** or a jigsaw. It takes an extra five minutes per stringer but keeps the structural integrity of the wood intact. Anyone telling you it's easy while hacking away with a 7-1/4 inch blade and overshooting every mark is just lazy. They’re relying on the fact that most homeowners never look at the underside once the finish work starts.

If I were the GC on that site, I'd be telling the client to demand a redo before any more material gets wasted. You can't realy fix an overcut stringer once the meat of the wood is gone. And if he’s that sloppy with the framing, his finish work is almost certainly going to be a mess of wood filler and oversized trim. Better to have the uncomfortable conversation now than deal with a structural failure down the road.

Man, as someone just starting out, this is exactly why I'm terrified to hire out anything. I've been watching a ton of videos on stairs becasue I want to try a simple deck set, and every single one warns about those overcuts. If a 'pro' with 18 years is doing this, how do you even vet someone? Is there a specific way to bring this up to a contractor without sounding like an annoying DIYer who thinks they know everythign? I’d hate to be that guy, but I also don’t want my stairs collapsing because I was too shy to point out a saw cut.

That '18 years' line is the biggest red flag in the trades. It usally just means they’ve been doing it wrong since the 90s and nobody had the guts to call them out. If those overcuts are deep, he’s basially turned that 2x12 into a flimsy 2x6. I’ve seen hacks try to fix this by scabbing 2x4s onto the side of the stringer, but that’s just hiding a structural failure. If he’s that careless with the framing, I’d bet anything his math for the total rise is off too. Check the bottom and top steps—I bet the heights aren't even consistent with the rest of the run.

It’s always the guys with the cleanest trucks and the fancy brochures who pull this stuff. They spend more on marketing than they do on sharpening thier blades. If he’s leaving gaps big enought to see light, I’d bet my lunch he didn't even check if the subfloor was level before he started his layout.

Once those treads start shrinking and expanding with the humidity, those gaps are going to turn into a drum set every time someone walks up. I'd check his math on the rise too; guys who overcut usally can't be bothered to calculate for the finish floor thickness either.

I bet he didn't even check the crown on those 2x12s before he started hacking away. If you don't put the crown up, the weight of the stairs will just make the whole thing sag and open those gaps even wider. I spend more time with my framing square and a set of brass stair gauges than I do acutally cutting. If your layout isn't dead-on and consistent to the 1/16th, the wood isn't going to magically seat itself. Seeing light trough the joinery is just embarrassing.