Working in a large model, fog does not work as intended

I’m working on a large project, that has context of the surrounding neighborhood included. When working on the elevations I am trying to give clarity through depth by using the fog to slightly fade the buildings to the back of the lot.

When using the fog slider it does not have a ‘roll in’ effect and instead the whole screen uniformly fades. I am wondering if this is a bug, or whether our model is just too big or what?
Any help would be great!

You are new to the forum and may not be able to include images yet. When you can, could you show your fog settings, and a screenshot of what your scene looks like?