I just finished a brick patio for a neighbor and saw something wild! We picked a quick-set mix to save time. After two days, hairline cracks appeared all over the surface. A guy from the supply house told me this blend reacts badly to morning dew. He said it needs perfect dry conditions to work right. Now I tell my clients to avoid it for outdoor work in humid areas. It's not worth the risk of callbacks. Stick with standard mortar and let it cure naturally.
