Hello yanti sweetie !! Thank you to you and to my dear Rose :D
Finally I could solve the error with the roof. I was adding more new features such as windows, doors, new columns and fences. I was playing with the decor as well, but I didn´t decided any definitive about ornaments with plants:
http://i1145.photobucket.com/albums/o510/AIRIS6962/Screenshot-456.jpg
http://i1145.photobucket.com/albums/o510/AIRIS6962/Screenshot-455.jpg
http://i1145.photobucket.com/albums/o510/AIRIS6962/Screenshot-457.jpg
http://i1145.photobucket.com/albums/o510/AIRIS6962/Screenshot-458.jpg
