To find the surface area of the walls, take the total length and multiply by the height. For a square room that would be 4 * length * height. For a rectangular room then ((2 * length1) + (2 * length2)) * height. For a room of any shape, just set a start point, then measure all along the wall until you end up at the same place, then multiply by height.
For the floor and ceiling, basically the same thing, take length * width and that should be.
If the celing is sloped, or vaulted, then split it into flat areas and add them up. 3D floor plans
