I would break it up into various rooms, approximately 10 feet by 15 feet each, though a longer one with a long narrow (2 feet?) water feature against the wall and seating and plants in the center part would work. Plants on the wall, making it vertically green. A path leading from room to room should jog, so you cannot see straight through. Change the theme of rooms, large fancy pottery, an outdoor dining area, sunbathing area if possible.

Congratulations to all of you. Its a wonderful platform to be on and you all are doing a great Job. My favourite Design Style is 'Minimal'. I just have this strong connection with simple, subtle and elegant things. Cheers:)

You can use natural stone like marble for floor but do not use granite for floor at all as it is very slippery when wet. As for tiles do not go for glazed vitrified tiles for the floor for the same reason. ( floor becomes slippery once wet and may cause mishap) Go for ceramic anti skid tiles that are specially meant for bathroom floor. For wall tiles you can use whatever you like and then decide over the matching anti skid floor tile/ marble. Double charged vitrified tiles are usually used for flooring in rest of the house.

Yogender Sharma To make a grass cover, the first thing you will need to ensure if whether the structure of the half basement is capable to holding a green roof. The next would be to waterproof the top again, keeping in mind the soil and the constant contact with water. Once these things are done, you need to locate were it is you want the lawn and ensure you have access to a drainage within or at best near it the area. You will then require the services of a horticulturist to help you set up the lawn. In terms of cost, it really depends on quite a few factors Existing condition of the structure Location Quality of Horticulturist Type of Green Cover etc....