My sims can't use the stairs that lead to my basement for some reason. I remodeled Beau Chateau from Riverwood by expanding it and adding a basement, but I never bothered testing the basement stairs because I have never had a problem like this before. It is on a foundation, but I used a method to add contiguous stairs from the first floor to the basement without using any cheats. I used this same method in another house without any problems. I have tried deleting and rebuilding the stairs completely, clearing my cache, resetting my lot as well as building the stairs in different locations and orientations, but I simply cannot get them to work. The small stair section that goes through the foundation seems to be causing the problem because when I delete it and clear enough space for my sims to enter from outside the house, they can use the basement stairs without any problems. However, when I replace the foundation and the small stair section, I can not get it to work with this particular house. Is there anything else I can try to get this to work? Thanks.
Edit: I still can't get a contiguous set of stairs to be functional, but if I stagger the small section as MeestorMark suggested then it works perfectly.