Just had a 750 sqft stamped concrete patio installed by a local concrete company but 80% turned out rough and looked much different then the other 20%. I reached out to the owner and he said this was a common occurrence under decks. I would be more accepting of the final product if it was in a small area or only 20% was affected, but it the majority. Is there any way to fix this?

Not the greatest photos but can someone tell me why this happens.