[avasylev]

From my anecdotal experience, a lot of recent immigrants (legal or illegal doesn't matter) don't know English and it takes them time (some times many years) before the can work in English speaking environment. Naturally such groups of same ethnicity are formed, and typically are the only work option for new immigrants (who don't speak English). This also means they are paid less, as have limited job options.

I'm not sure if I understood correctly, that your dad's crew was mostly immigrants, why do you think it was like that? If pay was good and semi-skilled (easy to train), why mostly immigrants?

[curun1r]

He probably could have found Americans to do the work, but I think he preferred immigrants because they were more willing to get paid under the table. He wasn't trying to dodge taxes, he just hated complexity and filling out forms. He was an artist who learned to see roofs as art and fixed them as a concession to needing money that he never could earn from his painting and photography. I think he was paying enough to find Americans, but not enough to find Americans who would stay with him for years, especially since it was seasonal work and they'd need other work during the rest of the year. Continuity and quality were also really important to him and he wanted people he could trust.