Nearly succeeded! Thanks for the idea, at least i learned to make a Custom Brush! 
The problem still exists as the walls aren’t 90 degrees. And for some reason two corners were cut like this one and two of them were sharp?
The House:
://i1292.photobucket/albums/b569/Nuutia/Unreal%20Engine%204/landslide02_zpsz0qmrvko.png
And here is my Custom Brush:
://i1292.photobucket/albums/b569/Nuutia/Unreal%20Engine%204/CB_fathers_house_base_zpswurqgm2t.jpg