Attach a Garage to a House With a Foundation in Sims 2 Nightlife

This neat trick will create a house with the garage attached to it, with foundation leveling inside.

Steps

Start with the base of your garage. Add a driveway and driveway extension on your lot.
Create a base foundation rectangle one tile away from your garage. This will be the base start for your house. Remove two foundation tiles for steps.
Add the steps along with railing inside the foundation.
Add the back wall. You'll notice that you can't connect to the house.
Turn on the cheat. Press "Control" "Shift" "C" simultaneously. Type in boolprop constrainFloorElevation false in the white box and press "Enter".
Connect the walls to the house. Do the same with the front, as you'll see "spiked" walls, which is going to be fixed soon.
Get the "Level Terrain Tool". Set it on a foundation tile and drag it across the front half of the garage.
Repeat it for the back section and you'll see that the garage "ground" is leveled with the foundation of the house.
Create walls around the garage and the foundation.
Add a garage door to the front wall. You also have the option of choosing the color of the door. You'll see that the wall above the door rises, which is going to be fixed soon.
Go to the top floor. Get the level terrain tool and drag it diagonally behind the garage rise to the "tile" next to the door wall. Let go and you'll see that the garage top is leveled down.
Remove the cheat by typing in boolprop constrainFloorElevation true in the cheat box.
Add color to your walls and garage.