Old stone steps can deteriorate over time, leaving the mortar between the stones loose or crumbling. If this occurs, it is important to repair the steps to maintain a safe surface to walk on. The mortar between the stones must be chiselled out and repointed with fresh mortar in a two-part process. The first part is called tamp pointing and is followed by finish pointing. Two different mortars are used for the mixes. The end result will be a sturdy repair for your stonework.
Chisel out the loose or crumbling mortar joints in the stone steps until you reach solid mortar, approximately 2 to 3 inches. Tap a masonry chisel with a masonry hammer as you guide the chisel along the joints to clean it out.
Brush any loose debris left behind by the chisel out of the joints, using a wire brush.
Mix seven parts sharp sand, one part lime and one part cement in a mixing trough with a trowel. Slowly add water until you reach a stiff batter-like consistency.
Pack approximately half of the depth of the cleaned-out mortar joints in the steps with the mixed mortar, using the tip of a pointing trowel. This is called tamp pointing.
Mix six parts sharp sand, one part lime and three-quarters part cement in a mixing trough with enough water to create a stiff batter mix, using a trowel.
Fill the remaining depth of the tamp-pointed joints with the mortar you mixed in Step 5, using the point of a pointing trowel to finish-point the joints. Drag the tip of the trowel across the finished joints to smooth the surface.
- Inspect stone steps seasonally, and make small repairs to the mortar as needed to maintain the stonework.
- Wear eye and hand protection when making stone step repairs.