I saw a while ago requests about it and found out an easy way to do so. Maybe this is helpful... at least I didn't find solutions as easy as this one.
When you have Numenor's walls you can even remove parts of the fountain next to the garage later on for a split level house but be careful, in this case my game crashed sometimes!
It's save when you are fine with a house on a fountain above a garage in the basement/ cellar

I don't want to write a complete tutorial with pictures (if it's required because my description is not clear enough tell me and I'll write a complete tutorial with screenshots, download version etc. though I hope it's easy to follow as is), here are just the steps:

1. Place the driveway and extension(s), for one or more cars.

2. Add the garagedoor(s) and two tiles of walls only next to the garage door(s) and finish the garage with a 'one-tile-row' fountain around the extension (this one-tile fountain will be the wall of your garage!). For now you have to keep one tile between the fountain and the wall free. For further cellar rooms and your house place further fountains, of course. You can already now add walls on the fountain.

3. Lower the ground inside your garage (= the room between the fountain and the extension) until you reached the height of the fountain. The extension won't be lowered for now.

4. Turn on (ctrl + shift + c) the cheat BoolProp ConstainFloorElevation false and lower the ground inside your garage, the inner walls of the fountain included. The extension will stay in the air first (instead of the ground underneath) while the garage door should move with the walls.

5. As the cheat is turned on you can now add walls left and right of your garage door(s) - the space which had to stay free earlier. Now your garage is a closed room.

6. Choose a tile that makes it easy to see differences in height and start to lower the driveway, create a sloped driveway - as far as you can see it for now.

7. Remove the driveway and extensions.

8. Undo! Important: Use the Undo- Arrow, otherwise this won't work!

9. When the driveway appears again it lays on your sloped ground and the extension is on the ground of your garage. Finish the slope-shape of your driveway(s) with lowering the ground (remove the driveway(s) and undo until your sloped driveway is finished).

10. Don't forget to flatten the ground on the next level ("house area") before you turn off the cheat (BoolProp ConstainFloorElevation true).
Now You can go on building your house!

Have fun!

Last edited by Khaibit : 27th Oct 2006 at 12:26 AM.

Thank you for your explanations Khaibit, just add 2 pics after the 2nd and the 4th points.

For the driveway this is only a visual effect, If you forgot the undo/redo phase it will be on place, sloped and lowered, next time you enter the lot. With the undo/redo way you can see easily what you did.

Nice to help
OK, here they are - and the undo/redo steps are easier to finish the sloped garage without re-entering the lot. You can finish building in one step

Last edited by Khaibit : 27th Oct 2006 at 12:15 AM.

This seems to be exactly what I was looking for. Thanks!
A question though, you meant "foundation" when you said "fountain"? I'm confused...

edited:I'll assume it's foundation. Translations can be hard some times!

I'm so glad I found this tutorial, it helped me make my dream house! Thank you!