Problem: The mortar around your stonework has become cracked and loose. You can't fix it by just adding more mortar, because it will become loose again within a few months.
Solution: You can fix the stonework by removing the old mortar and replacing it with new mortar, a process known as "tuck pointing."
Equipment list:
Mallet
Masonry chisel with narrow bit (some newer chisels have a safety guard)
Pointing trowel
Bristle brush
Wire brush
Safety glasses
Safety gloves
Stonework is one of the most durable building materials. It's resistant to all the elements except ice. Sometimes water will seep through cracks in the stones or mortar. When the water freezes, it expands and pushes the stones out of position.
- If you feel uncomfortable using a chisel for the first time, practice on a chunk of old concrete or a cinder block.
- Always wear safety glasses when using striking tools.
- Chisel away the soft mortar. Keep chiseling until you reach the strong mortar underneath. You will need to remove at least 1/2 inch for the new mortar to have a good bond.
- Remove any loose stones and clear away the debris with the wire brush. This will give the new mortar the best surface for good adhesion.
- Mix your new mortar according to the manufacturer's directions. Most mortar is mixed to the consistency of oatmeal.
- Dampen the repair area with water. This will help prevent the existing stonework from absorbing the water from the new mortar. The water content of the mortar will determine how well it cures, so you don't want it to evaporate too quickly.
- Apply new mortar to the area with the pointing trowel. Add as much mortar as you think you'll need.
- Set the stone in place and secure it with a twisting motion.
- Add more mortar to fill all the joints. Work slowly and carefully until you fill all the areas around the stone. After the mortar cures for a few hours, you can wipe away the excess mortar with a brush.
- The new mortar will look different from the surrounding mortar for a while, but it will match after it weathers.
- A haze will appear on the stone, but it will weather away with time. You can also brush some of it away after the mortar has cured completely.
- If you take care of small problems as they crop up, you can prevent larger problems from occurring later.
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