Oops. I forgot to say I posted this in the porch/deck section but things seem very quiet there so I thought I'd get more carpenters reading here for opinions.

The router method you speak of is the old fashioned way the earliest that I have seen was 1764 around this same time it was also conmen to nail cleats to the stringers for the treads and risers. The router method has made a come back in the last 10 years or so. It makes for a tighter skirt board with less effort how ever all the treads must be attached to all the raisers to form a single unit. This method also nearly eliminates squeaking. How ever I would think that 4Â is a little far for no support in the middle and any bounce is completely unacceptable. All wood that comes in contact with concrete should be treated. My personal opinion is that the front where there is one 2x4 should be doubled and all the cleats that are nailed to the wall should have 2x4 from the deck to the floor. The latter my be over kill but thatÂs how II would have done it.

Simpson has stair angle brackets that basically are similar to angle iron.For your tread to stringer connects, you could lag these brackets in to strengthen the 1/4" dado connect.You could go with simpson, or get some 1-1/4" angle iron 3/16" thick, drill some holes for your lags.If you can, cut in a pressure treated 2x4, notching your stringers to allow the 2x4 to lay horizontal from stringer to stringer, then add a center stringer as mentioned above.When you notch the p.t 2x4 in,make the notch 1-1/4" to slightly hold the stringers off the concrete.The 1/4" wont affect the feel to the step.

That makes sense. Thanks for the info.

I spoke to the builder. He told the carpenter to make the stairs look nice, and build them like an interior staircase. My mistake, the grooves are 1/2 in deep. The builder says he never uses pressure treated wood in interior garage stairs, and prefers open risers as it's easier to sweep out under the stairs. The treads have a 1" gap in the vertical dimention to the next step ie an inverse stair nosing. If I look down I can see the ground between two steps. Great if I drop my keys.

I feel like tearing the whole thing out and rebuilding it myself. Oh well, I've only already paid a few hundred for this I'm sure, however much is built into the house price! I shouldn't be irritated so much by such a little thing, but I am. These stairs WILL get changed.