Porkpal, our last house was a quad level. We had carpet at the ground level garage entry and I always hated how dirty the carpet was, so we pulled it up with the intent of tiling a big area in front of the door and at the bottom of the stairs. AFTER cutting off the carpet, we noticed a bump in the concrete where the slab had settled away from the piers. We didn't think about getting a jackhammer. Instead, we had to lay new carpet in a big room. What we did was draw a curvy line that left the bump under carpet and tiled the rest. It looked pretty artsy because we had a good carpet guy and I did the tile.
In the older house we're in now, we had to jackhammer out a portion of the basement floor because I moved a staircase and we had to pour support piers. The surprise there was the old basement floor was 8" thick. Way way better than current code. Concrete was so much cheaper in 1967--the porch and patio we tore off was 8" thick also! Too bad it had settled towards the house instead of leaning the other direction.
We kept a big part of it and put it out in the yard under the firepit. The previous owner had scratched their initials in the wet concrete with the date and we thought that was worth keeping.
The rest was recycled as riprap on our low water bridge.
