Don't have to worry about marring the floor (concrete), but I wouldn't tape it directly to the floor anyway (too hard a surface, need some underlay, etc.).
Good luck in your home dojo. We have had Zebra mats (tatami green) directly on concrete for about the last six years at the Jiyushinkan and have no problems. Everyone found their ukemi getting better and we take lots of falls.
My son just bought a house about 45 minutes north of Seattle with a space in his basement that's similar to yours (almost 1000 sq. ft). He's putting Zebra mats in soon. His ceiling is 10'. When he gets the outdoor dojo built, I suspect the basement will become the home theater room...