You can get them by watching youtube videos. I re-roofed my own house (I simply couldn't afford to hire a crew). After the job was done I compared to other hous

You can get them by watching youtube videos. I re-roofed my own house (I simply couldn't afford to hire a crew). After the job was done I compared to other houses in my neighborhood - my roof had straighter lines and looked better than any roof I could find.