Hmmmm, how do you do that?
In essence the same way as Turkishswede did it with LukesDarkUfo mod. Placing internal west and north walls to block lof.
I modified ufol83.mcd slighty to have a west/north wall corner tile with another loft just to make sure.
the additional walls do increase the ammount of recovered aliens alloys slightly , 10 additional tiles 1 alien alloy.
i can post a few screenshots later if you like.
it was a rather time consuming process...