How can I fix a settlement crack in stone(round creek rock) fireplace?

Would like to do something about it before putting house on market because buyers assume it is a problem which it is not
  2 answers
  • Tab Bisignani Tab Bisignani on May 28, 2017
    Cracks in Mortar Joints
    1. Clean the cracked mortar joint with a wire brush. Remove any larger loose particles with a chisel and hammer as needed, removing up to (but no more than) one-third of the depth of the mortar joint. Blow out the debris with the blower attachment of an air compressor hose to eliminate any fine particles from the crack.
    2. Pour a bag of mortar into a mixing tub or metal wheelbarrow. Add half of the water called for on the bag's mixing instructions, and thoroughly mix the mortar with a trowel until the mortar can be mixed into a well-formed ball that holds its shape.
    3. Allow the mortar to sit for an hour, then mix in just enough water to make the mortar pliable but still stiff.
    4. Wet the damaged mortar joint with a bucket of water and a brush. Tightly pack the joint with a layer of mortar 1/4-inch thick from the edge of the existing mortar, using a tuck pointer. Tightly push the mortar tightly into the joint to eliminate any air pockets, then add additional 1/4-inch layers until the joint is packed fully to the front edge of the stone.
    5. Allow the new mortar to sit for 30 minutes, then drag a masonry jointer along the edge of the joint to smooth out the mortar.
    6. Brush the mortar joints with a brush to clean away any excess mortar from the joints.