If there is a toilet involved, yes.I'm installing laminate flooring in a 5x7 walk-in closet that is connected to the bathroom. The floor in the closet and bathroom is flat, but slope towards the same direction. The slope in the closet is 1", as well as in the bathroom (the tub is level).
I've looked at ways to level the closet, including using roof shingles, removing the underlayment to inspect the joists, self-leveling cement, and long 1x1 shims on the bottom underlayment. I don't know which I should do, but I'd rather avoid getting to the joists as there doesn't seem to be signs of structural damage.
If I level the closet, the tile-laminate transition between the bathroom and closet won't be level. If I also level the bathroom, I'll have to learn real quick how to do a floor tiling. Is the slope even something to worry about?