How to Identify the Need for and Execute Repointing


Securing Your Chimney: How to Identify the Need for and Execute Repointing


Maintaining your chimney stack is essential for the safety and integrity of your home. Repointing, the process of renewing the mortar joints, is vital in preserving its structural stability.

Recognizing when your chimney requires repointing and understanding how to carry out this maintenance task effectively can prevent potential hazards and costly repairs.

This guide will cover how to identify the need for repointing a chimney stack and outline the steps to do so.

Identifying the Need for Chimney Repointing

Before jumping into the repointing process, it’s crucial to determine whether your chimney requires it. Here are signs to look for:

  1. Mortar Erosion: Check for signs of erosion in the mortar. If the depth of the eroded mortar is 1/4 inch or more, repointing is necessary.
  2. Cracked or Crumbling Mortar: Visible cracks or crumbling in the mortar joints are clear indicators that repointing is needed.
  3. Loose Bricks or Stones: If bricks or stones in the chimney structure are loose or moving, it’s a sign that the mortar has significantly weakened.
  4. Water Infiltration: Signs of water leakage inside your home near the chimney area can be due to failing mortar joints.

Tools and Materials Needed

  • Mortar mix suitable for chimneys
  • Trowel
  • Hammer and chisel
  • Stiff brush
  • Ladder or scaffolding
  • Protective gear (gloves, safety glasses, dust mask)

Step-by-Step Guide to Repointing a Chimney Stack

  1. Ensure safety: Securely set up scaffolding or a ladder for safe access. Always wear appropriate protective gear.
  2. Removing Old Mortar: Gently chisel out old and damaged mortar to about a 1/2-inch depth. Be careful not to damage the chimney bricks.
  3. Clean the Joints: Thoroughly clean out the joints with a stiff brush to remove dust and debris, ensuring a clean surface for the new mortar.
  4. Mix and Apply Mortar: Prepare the mortar mix as per instructions. Apply it carefully to the joints using a trowel, ensuring it’s firmly packed.
  5. Finishing Touches: Once the mortar starts to set, finish the joints to match the existing style. Clean off any excess mortar from the brick surfaces.
  6. Curing: Allow the mortar to cure as directed, avoiding any repointing in extreme weather conditions.

Professional Help vs. DIY

While minor repointing can be a DIY task, for high or severely damaged chimneys, professional assessment and repointing are recommended. Professional masons have the expertise and equipment to safely and effectively carry out the task.

Maintaining a Repointed Chimney

After repointing, regular inspections are key to early detection of any deterioration. This proactive approach ensures the longevity and safety of your chimney.


Knowing when and how to repoint your chimney stack is crucial in preserving the functionality and safety of your home.

Regular inspections, timely repointing, and proper maintenance are essential in keeping your chimney in optimal condition, and safeguarding your home against the elements and time.