The inside of the Brady residence bears little relationship to the outside.
From the exterior front, we see what appears to be a split-level home with the two story part on the left. Yet, from the interior, we get the feeling that the two-story part is on the other side.

In addition, is there a "back yard"? The astro-turfed area seems to be to the side of the home.

uuuuuuuh--can someone draw me a floor plan so I can begin to comprehend the house!!

The window on the exterior of the house was fake. It's interesting that they filmed all the shots of the house before the series even started and just recycled them through the shows run.

Read more about the house here:
http://davidbrady.com/times/latbrady.html
http://www.bigwaste.com/photos/ca/brady_bunch/

blueprints:
http://www.unc.edu/courses/jomc191/mirrors/bradys/bbhshist.htm

THANKS, TJ. I ENJOYED LOOKING AT THE BLUEPRINTS FOR THE BRADY RESIDENCE...
I STILL THINK THE DESIGN IS WEIRD AND THE CAMERA SHOTS SEEM TO BE INCONSISTENT WITH THE PLANS...OH WELL............

The set was designed/built before they chose a house for the exterior shots. It was decided that the house seen in the exterior shots was perfect for the show (had just the right feel) but it was a ranch and the two story set had already been built, so they added a fake window to make it look like a two story house.