I have a fair amount of high-temp mortar on the firebricks. I learned this when I removed the styrofoam. I know not to fill in cracks because it will weaken with heat and crumble in time. My question: since I already have the high-temp cement on the ceiling, should I leave it alone or grind it off?
Congratulations on getting your bricks done! There are different thoughts on this subject. One is, leave it, you won’t be able to see it after you do some fires. I chose to use a angle grinder and a wire wheel to “softly” wear down the mortar. I caused no damage. There is still a little excess mortar but i am happy with it. It is a personal choice in my opinion.