- House by: #Sophiesaba -safesimmer renovation- ART BY: #Fruitsloops40 #Juste1souvenir #Mbarnet - 1) How to do the trim: Add 'flat square, when you hit the b key, and drag it out' to your roof, along the entire surface. Under where you find the roof trim, there's a section for another kind of trim. There are two kinds here. Under the first one, is the smaller trim. I recommend using this. 'Jutting Exterior trim' is my personal favorite. After applying the trim, do your roof.