Except for that slope the floor itself might be flat.
How to make a sloped floor.
Draw a slope arrow while sketching or editing the floor boundary.
As soon as you place the point revit resolves the new surface by triangulating it.
A slant slope situation might be one where over the course of 15 or 20 horizontal feet the floor slopes down one or two inches.
For rooms that have a general slope the issue may be foundation problems that require the assistance of a foundation repair company or a general contractor.
You can create sloped floors in the building model.
Use one of the following methods.
If we switch to a 3d view it is far easier to see what is going on.
You can envisage that this point may represent a drainage point in our floor that we want to slope down to.
Specify a value for the defines slope and slope properties for a single floor sketch line.
Specify a value for the offset from base property for parallel floor sketch lines.
Make sure you place it within the boundary of the floor element.