ROOF DECKS in cities where space is a luxury, a roof deck is like a surprise “present.” penthouse units or condo units in a terraced building are usually lucky to have roof decks. here are some ways to utilize this outdoor space. 1. Urban garden. create your own city oasis with a potted garden; small trees are also welcome, as long as they fit in the service elevator! make sure you have proper drainage (and a faucet) in the area for when you water the plants. 2. An additional “room.” condo units have limited floor area, and a roof deck is a wonderful opportunity to create an extra “room,” be it a seating or lounge area or an al fresco dining spot. use weatherproof upholstery and materials. 3. A smoker’s lounge and bar. add a few cocktail tables and chairs, a weatherproof bar, plus ashtrays, and your home will be your friends’ favorite hang-out spot. 4. An observatory. place a couple of telescopes and a seating area, and you’re ready to view the night sky (among other things).