This tutorial shows how to attach a garage to a "lowered foundation" - or, actually, ANY foundation - with the Grid-Adjuster

YOU WILL NEED
Mootilda's Grid-Adjuster Tool ...obviously!
Simler90's Stair Mods to allow large dogs access if you are making a 2-Click/2-Step Foundation House.

AND I SUGGEST READING
Moo's own G-A Tutorial
My other Grid-Adjuster Tutorials...

This tutorial assumes you are already familiar with TS2 building techniques and the Grid-Adjuster (somewhat familiar, anyway!)

Instructions:
The house built for this tutorial has specifically a 2-click/2-step foundation. BUT, the same technique can be used for regular 4-click foundations, or any height you need. Just modify the Grid-Adjuster settings accordingly.

You could've also used the foundation tool to create the foundation level.
In fact, if you are doing a 1-click/1-step foundation, I recommend using the foundation tool - because you must use HL's SimplePassageModularStairs, to allow sims access to the 1-click/1-step foundation, and they must be added while the house has a 4-Click foundation.

No need to "count out" the areas of the house - unless you are making a no-slope basement (which is not what this tutorial is about!)

(Just leave the red-lined items alone. Don't change them at all!)

Don't worry about turning the cheats off. They will reset when you exit and restart the game.

The G-A setting for a regular 4-click foundation is: Elevation = 20 (16 + 4)
...for a 2-click foundation is: Elevation = 18 (16 + 2)
...for a 1-click foundation is: Elevation = 17 (16 + 1)

Here is the link for Numenor's Unlevel Wall - #90.

If you have any Grid-Adjuster questions, please post below or shoot me a PM. I haven't learned everything there is to know about it yet, but I'm gaining lots of experience! And, I'll help if I can!

This house is uploaded here: Modest 4B Ranch - in case someone wants to reverse-engineer it to see what I did.

Good luck!