Foundation Sliders have gone missing

Issue

The sliders for the foundations are gone since Patch 1.47.49.

Cause

The patch made it possible to individually set the foundation height for each unconnected building. You can now have buildings with different foundations.

Because of this, the slider was removed from the GUI and it’s working differently now.

Solution

Choose a room to which you want to add a foundation. You should then see an up/down arrow with which you can change the foundation for each building.