Hi helen, it's good to see you back!

I understand the "catwalks" of which you speak but they are uncommon enough here that I can't think of a word for them. The "private terrace" you describe, I would call a balcony. I think that's our British heritage seeping in. I think of a deck as necessarily being made of wood, and a patio being close to the ground, and not made of wood. Usually stone, I guess, or cement.