Thanks guys! Turns out it was not just the tallest wall driving the roof elevation, it was the tallest object/furniture! All sorted, thank you

And screenshot of the floating roof for anyone not loading the full file: https://www.mediafire.com/view/0edghd8i ... 9.png/file

Oops! Here you go: https://www.mediafire.com/file/uredbv8r ... .sh3d/file

Downloaded that version, restarted it and all looked ok (screenshots in mediafile also). Tried a new roof, same issue. Hopefully you'll see something wrong in my settings or how I am doing this, but I can't find it!
SH3P file:
https://www.mediafire.com/file/9sltw8oklhlol1s/GenerateRoof_%25283%2529 ...

This forum doesn't support attachments so how do you want the files? I have the screenshots showing ver 7.1.1 and ver 4.0 beta 2 for the roof generator.
Cheers

Version 4.0, and @Louis, I'm not adding anything other than a floor, then roof? Even if I place a floor on a new space on the drawing, where nothing has been before, the roof is about 6m up!

My roofs are all way up in the air, even with elvation at 0? What am I doing wrong?