The US clamped down on Mexican border crossings. Guess what? There’s no labor. Who would have thunk it.
Now, the border is more porous than ever. There's plenty of labor -- go to any home improvement store parking lot. And that's just the illegal labor -- boost wages and you could recapture legal workers.
But for now, go to any construction site in California, and you'll hear only Spanish spoken between the carpenters, roofers, etc. and their supervision.
I wouldn’t assume all or even most labor on constructions sites are illegal immigrants just because they speak Spanish, if only because the USA has a lot of legal first-gen Hispanic immigrants.
Back here on earth, roofers are making $36/hr. My brother’s restaurant is paying $28-32/hr for line cooks and dishwashers.