I realize that there's a door in the bottom picture where there was a window in the top picture - it's because we added on a giant master suite to the rear of this property. Our first addition ever. And just in case we didn't have enough to manage on this renovation, we did another addition on to the front of the house as well. But that's another post for another day.
This house was a 3000+ square foot, 3 bedroom, 3 full bath home when we purchased it. All of the bedrooms were on the top floor, with the living areas on the middle floor, and a walkout basement with full living room and garage on the bottom floor. It's in a higher-end area of Louisville called Rolling Fields, adjacent to the highly desirable Country Club section of Indian Hills.
In this area, we knew we had to create at least a fourth bedroom - three bedroom houses don't sell in this area because it's almost all families with children. Additionally, the existing master suite wasn't going to cut it in this area and price range: it was a nicely sized room with hardwood floors and several windows - but the closets weren't walk-in and the bathroom was small, and only allowed for a 36" vanity and a good-sized stand up shower. Now, in another neighborhood and price range, this setup would be perfectly fine. But this property is located in a neighborhood where sales START at around $450k for the smaller houses needing tons of work, and go up to $1 million-plus. We HAD to meet the neighborhood "standards" or this house would never sell.
SO - we decided the best way to do this was to add a master suite onto the rear of the home, off of the living room. There was an unused, flat corner of the backyard that seemed like the perfect spot for it. Upon further inspection, it was definitely the place for it since all of the plumbing was in the rear of the house, and accessible by crawl space - making running plumbing to the addition about as efficient as it could get. I don't have official measurements/design drawings of the ground floor layout that the house had when we purchased it, but here's a quick sketch that is NOT to scale: