I have a 25 yr old brick home with a stone fireplace on the inside the home, brick on the outside. The stone part is made of the, for lack of knowledge, plates, that are embedded in mortar. The plates seem to be starting to crumble. I don't detect any moisture. I live in southeastern USA and my interior temperature is kept around 68 winter and 73 summer. Will I have to replace this or can it be repaired? BTW we have not used the fireplace for about 15 years. Thanks!

Hi Rockitman and welcome, do you mean the stones are crumbling? Can you post a picture.