How to Repair a Brick Chimney: A Step-by-Step Guide

Brick chimneys add aesthetic appeal to a home’s exterior and are crucial in venting smoke safely from a fireplace. However, exposure to the elements can lead to deterioration over time. At SVD Restoration, we want to help you preserve the integrity and safety of your brick chimney with some DIY repair advice. Whether you have cracks in the chimney crown, bricks, or mortar, addressing these issues promptly can prevent costly repairs down the line.

Project Overview

  • Working Time: 2 – 4 hours
  • Total Time: 1 – 2 days (including drying time)
  • Skill Level: Intermediate
  • Estimated Cost: Around $150 – $200


Signs Your Chimney Needs Repair

  • Cracks in the mortar or bricks
  • Deterioration of the chimney crown
  • Loose bricks or missing mortar
  • Evidence of water leakage inside your home


 Before You Begin

  • Check Local Codes: Verify if a permit is required for more involved chimney repairs in your area
  • Check Weather Conditions: Only conduct these repairs in suitable weather—above 40 degrees Fahrenheit and with no rain expected within 24 hours.
  • Ensure Safety: When working on a roof, ensure you take precautions against falls. Use non-slip footwear, work on a dry day, and consider a safety harness if the roof is particularly steep or high.

Tools and Materials Needed

  • Sturdy ladder
  • Masonry chisel
  • Hammer
  • Wire brush
  • Joint raker
  • Tuckpointing tool
  • Mortar mix
  • High-heat mortar caulk
  • Caulk gun
  • Putty knife
  • Garden hose
  • Safety glasses
  • Fall-arresting harness (optional but recommended for steep roofs)
  • Masonry sealer (for hairline cracks)
  • Latex gloves
  • Clean rags
  1. Repoint Brick Mortar:

Begin by scraping out the loose mortar. A joint raker works well for minor crumbling. For more persistent issues, carefully tap the mortar with a chisel and hammer. Clear out the debris with a wire brush. Dampen the bricks slightly with water from your garden hose, then fill in the gaps with fresh mortar using a tuckpointing tool. Shape the mortar to match the existing joints and let it cure as recommended.

  1. Caulk the Flue and Crown:

Inspect the space between your chimney flue and the crown for gaps, a common entry point for water. Clean out the area, then apply high-heat mortar caulk for a weatherproof seal. Also, examine the step flashing and apply silicone caulk if necessary.

  1. Repair the Crown:

The crown requires attention if you see larger cracks. Use a pre-mixed cement patch or mortar, applying it with a squeeze bottle or putty knife. Ensure that it fills the cracks thoroughly and the surface remains smooth.

  1. Seal Hairline Cracks:

For smaller, hairline cracks, use a masonry sealer for a more penetrative fix. After cleaning out any loose debris, apply the sealer with a brush. This will not only fix the hairline cracks but provide additional protection for the entire area.

  1. Fix Cracked Bricks:

Bricks with small cracks can be remedied with high-heat mortar applied directly into the cracks. Ensure the area is clean before applying, then smooth the mortar and wipe away any excess.

  1. Replace Cracked Bricks:

If a brick is too damaged, it’s best to replace it entirely. Carefully chisel out the mortar surrounding the brick, remove it, then prepare the replacement brick with new mortar. Insert the new brick, ensuring it’s level with the existing bricks, and smooth out the joints.

When to Call a Professional

Early detection and repair of chimney problems can save you from more significant, costly issues in the future. By following these steps, homeowners can often handle minor repairs themselves. For peace of mind and safety, SVD Restoration is always here to provide professional evaluations and repairs for your chimney needs. Remember, maintaining your chimney is not only about preserving the appearance of your home but also about ensuring the safety of your living space.