Re-pointing a chimney refers to removing the mortar and applying new mortar to the areas surrounding the brick. The mortar joints stabilize the chimney and prevent water and debris from entering the inner recesses of the chimney. Re-pointing, also known as tuck-pointing, is necessary when mortar joints crack, crumble or otherwise fail. Exposure to freeze-thaw weather patterns often cause cracks and crumbling on a chimney, and may turn small cracks into large problems.
Position a hand-held power masonry grinder onto the mortar joint. Set the blade depth to 1/2 to 3/4 inch to remove old mortar.
Turn the grinder on and move it along the mortar joints to remove old mortar. Begin on damaged or loose horizontal mortar joints, then grind out damaged or loose vertical mortar joints.
Sweep out debris from the mortar joints with a hand-held whisk broom. Brush out stuck pieces of mortar with a wire brush.
Mix water and mortar in a bucket to form a thick paste, according to manufacturer directions.
Mist the mortar joints with plain water from a spray bottle. Misting dry mortar joints prevents the brick from sucking the moisture out of the new mortar.
Dip a trowel into the mortar and place the mortar onto a hawk. A hawk is a flat holder with a handle on the bottom, used for holding mortar as you fill in mortar joints.
Place the hawk up to the empty mortar joint with the edge of the hawk just under the mortar joint. Push mortar off the hawk into the mortar joint with a thin trowel. Press the mortar into the joint as far as possible. Move the hawk along the empty mortar joints, push the mortar into the joints deeply until mortar is in all joints.
Place a striking tool onto the new mortar joints and drag it along the mortar while pressing the mortar tightly into the mortar joint.
