Uneven concrete flooring

Hi, This is my first time in a forum so here goes.

I have a concrete slab that once was an out side area but now has been buit in. the slab was poured with a slope (away from the house) of around 1 brick over about 4 metres. I want to level it some how and place floorboards. Is the slope too extreme or is there a way to bring it back?

Hope to get a reply because i would love to tackle this myself if possible.

Ta:U

when flooring over it simply raise the floor by the required amount at the outside edge.

if you do not understand how to do this i can post pics to explain it.