Interior foundation problem

[Jocelynn]

Since I've installed AL I have an issue with building interior foundations, so I think this is the right place for this post.

Whatever I'm trying, how empty the exterior foundation is: When I'm trying to put an interior foundation over the exterior foundation it still keeps saying that I cannot place an interior foundation over a halfwall or fence.
But there are NO halfwalls or fences on the foundation below.
So, you can imagine this turns me  .
Tried everything: Leveling terrain, other lots, deleting all objects... but EA keeps saying it's impossible what I'm trying to build.

I wonder what's going wrong and how I can solve this problem?

[retrotrut]

I'm having the same problem....I tried removing all my CC and it still giving me problems. Any clue?

[miros1]

I'm not sure what an interior foundation is... but here's my best guesses:

1) If you want a foundation wall on the floor above the basement/foundation level, use a regular wall, save and quit the game, and use Mootilda's Wall  utility from MTS to make it a foundation wall.

2) If you're making a double wall foundation on the same level to hide the sloping grassy bits, use a regular wall on the inside.

[Theraven]

I don't think it's possible to place the interior foundations on the exterial ones (not without any mods, at least). Tried it myself, and it did not work. As far as I know you can only place them directly on the ground or on floor that isn't foundation.