I am hoping someone can offer some insight on what my problem might be. When I create a scene in Sketchup of my porch frame, the floor is not included (see first photo).
As @DaveR said, this is something that can be diagnosed easiest with a copy of the SKP file. It LOOKS like an issue with the transparent material you are using. I don’t think it is the floor, at the back wall is solid black, as well (and there is no floor out there, I assume).
That material is an image of a grid (a screen). I am guessing that, when it is being drawn in Layout, Those black likes are getting blurry and showing up as black. You may want to try replacing the mesh material with a transparent material, instead.
Here is a dark gray material set to 50% transparency:
If you zoom in REAL tight, you can see that it IS actually drawing all those lines of the screen. It’s just drawing ALL those lines for the screen. As you back out, the lines for the screen are overpowering the breaks between the lines: