This winter we did one side of a see-through fire place with stucco. It looks great! The effects of heat on this product aren't a problem. If you follow the label and apply exactly as the directions tell you won't have a problem. The only thing is that this product dries quickly. A two man project - one to apply and one to even it out (the thickness of this product on the fireplace is extremely important) you don't have a lot of time to get the stucco nice and even and "perfect" - so don't sweat it - practice a little on a piece of drywall, etc. Sometimes imperfection looks a lot better than a perfectly balanced application. Although I love the results, I remember during application I kept feeling that I was applying cottage cheese to a wall and trying to get it even. It went quickly (because it had to) but it was frustrating. The end results were worth the mess. Good Luck!