Tennis Court:
There is an area in the front yard completely surrounded by trees and bushes. It is large enough to fit / hide a standard size tennis court. The court used in the simulation photo comes from Marly-le-Roi’s Tennis Club. It is of course at scale with the aerial picture of the house.

(simulation)
Swimming Pool:
Swimming pools are not that uncommon in l’Etang-la-Ville, so it should not be too hard to find a solid pool construction company in the area. Some of them are even heated. This one was taken from one of our neighbors’ garden.

(simulation)
Both:

(simulation)
Turning the 3rd Floor into an Independent Apartment with an Elevator.
This could be convenient if you want to sublet, or accommodate a family member. The Grande Salle would make a beautiful living / dining room. There is already a kitchen installed, a bathroom, lavatory, and two nice bedrooms.
Terrace / Veranda on the roof, with 360 view of the whole region.
This may actually be the simplest project if you just want a terrace. A veranda might be a bit more complicated but would be ideal for the winter, especially on sunny days. There is already a spiral staircase leading to the roof, right above bedroom 7. That’s where the terrace would be. Right now, the opening is just big enough to get through. It would need to be enlarged for easier access. Also, the part of the roof to be used, the square surface right above bedroom 7, would need to be flattened, and a nice Art Nouveau metallic barrier installed all around.




