Way to go, a future fish house disguised as a garage.
So when the second tank goes in you can just park in the street again.
Cause lets face it stocking and maintaining this tank or 2 a new car is just out of the question.
Just a couple side notes.
Calling concrete "cement" is lile calling cake "flour". Cement is an ingredient in a concrete mix.
You get two guarantees with concrete:
It's gonna crack!
Nobody is gonna steal it!
Cement in away is easier in that you build wooden forms to hold it in and have it pored along at the same time as the concert slab when you build the building.