How to Replace Broken Mortar Around Brick

Replace crumbling mortar to restore your brick wall's appearance and stability.

Builders use mortar between bricks to create a tough, durable seal. Despite its sturdiness, mortar may break down over time due to erosion, acid rain, extreme temperature changes or stress. If the mortar in your brick wall is missing or breaking down in certain areas, you can mix a new batch of mortar to fill in the gaps.

Things You'll Need

• Pressure washer
• Hammer and chisel
• Re-pointing mortar mix or bricklayer's sand and Portland cement
• Colored oxide
• Trowel
• Joint ironing tool
• Wheel rake
• Muriatic acid
• Stiff bristle brush

Instructions

1. Power wash the brick wall with a pressure washer to remove dirt and debris.

2. Hammer into old, crumbling mortar with a chisel to a depth of 1 inch, or when you reach hard, solid mortar.

3. Mix a commercial mortar mix, or four parts sand and one part cement, with enough water to make a thick paste. To test the mortar's thickness, roll it into a ball. If it holds its shape, the mortar is thick enough to use.

4. Add colored oxide to the mortar to match the exact shade of the existing mortar. Let the mixture sit for 90 minutes before using it.

5. Place mortar on the flat side of a trowel and pack it into joints with a joint ironing tool or your fingers. Smooth the mortar flat with a wheel rake to blend it in with the existing mortar line.

6. Clean dried mortar from the bricks using muriatic acid and a stiff bristle brush. Thoroughly rinse the brick afterward to prevent acid erosion.

Tips & Warnings

• Dry mortar particles can get in the lungs. Use a dust mask when mixing new batches of mortar.

• Wear work gloves and eye protection when handling muriatic acid, and wash anything it comes in contact with.

References

• Masonry Magazine; Mixing Mortar for Properties -- The Prescription Mortar Method; Tom Inglesby
• Reader's Digest: How to Replace Brick Mortar