This is a very common problem I see when showing homes in the Chicagoland area. I know it can be a real pain for homeowners living in an area where the climate and gravity can be the cause of concrete porches and/or stairs moving away from the foundation....
Heavy things must be founded well. When they are not, over time, they will settle.
Stoops and stairs are mostly made of strong, heavy materials, like concrete. And when concrete stairs move, the foundation can't be far behind.
Generally you want stairs such as this to angle slightly away from the house.
That is so water is encouraged away and does not get behind, against the foundation.
These stairs have moved more than it appears from this photo.
They have actually moved quite a bit.
These stairs have moved about 1" away from the house.
But think of the shape of the concrete. The straight backside against the house is about 3.5' from top to bottom.
As the front of the stairs settles into the soil, and the top of that backside pulls away from the house, the bottom of that same backside is pushing AGAINST the house.
That concrete staircase is very heavy.
It is hard and strong. It is harder than the concrete block foundation wall, and can push very hard as it settles.
The result is a horizontal crack, outlined in red. This crack appears just where the bottom of that staircase would hit the house.
This crack begins under the one side of the porch and continues behind the wall on the right.
Foundations of concrete block will be subject to outside forces, including water/soil pressure, tree roots or other weight. In this case the outside pressure is created by a heavy, concrete monolith - a staircase which was not founded well. It has settled over time, putting pressure in the opposite direction of the settlement.
Try it yourself! Stand straight, bend at the waist as you put your head forward. Which direction does your backside go? It has to to maintain balance. This staircase stays balanced too.
Hard to see in the photo, but this crack is 1/4" wide.
That is a lot of foundation movement.
My recommendation: staircases such as these are subject to the forces of gravity. They will move if given opportunity. In this case we could see what was happening to the foundation wall. Had we not been able to see it I would have suspected this movement you see here. Look around for yourself if you suspect this too. You might just see what we saw!
Jay Markanich Real Estate Inspections, LLC
Based in Bristow, serving all of Northern Virginia