Chimney repointing

LAST UPDATED: 5th January 2023 by The Editorial Team

Chimney repointing

Summary: Step by step guide and video how to repoint a chimney stack, remove the old mortar and repoint the chimney stack brickwork.

Repointing a chimney

Over time mortar holding bricks together on a wall can come loose and break away. Damaged mortar can make a wall look unattractive and allow damp to penetrate. If left for a long period of time it can cause the wall to become unstable.

It is important to repair the joints in the brickwork of any wall to prevent further damage to its structure. This is equally important with regards to a chimney stack. If you find that mortar has become dislodged in places, then you will need to repoint the brickwork in question. If you do not see to the problem, it could result in water penetration, which will lead to more damage.

Removing the mortar

  • When taking on the task of repointing the brickwork, you need to prepare and plan beforehand how you are going to tackle the job. The height of the chimney will require a ladder or scaffolding. All safety aspects of the job should be thought about and met appropriately.
  • Gaining access to the chimney using a ladder may require a safety harness for added security or at least an extra person who can hold the ladder steady.
  • Firstly you need to clear out the old mortar, which has become damaged and loose. The tools that are best for the job depend on the toughness of the mortar. If it is soft and relatively easy to clear, then a screwdriver or joint raker would suffice. However, harder mortar may need a hammer and chisel to clear properly.
  • In particularly narrow joints, where other tools are too large, you may wish to use a hacksaw blade removed from the handle to scrape with.

Repointing the brickwork

  • Before starting the next part of the process, you need to be aware of the likely weather for the next day or two. If rain and/or frost are expected, do not undertake the task, as it will affect the new mortar.
  • Using a soft hand brush, sweep away as much dust and debris as you can. Before you apply the new mortar into the brickwork, spray or brush a little water onto the joints to dampen the area you will be working on.
  • With a hawk and pointing trowel, fill the joints in the brickwork with the correct mortar mix. You may find it easier and quicker to apply the mortar if it is laid on the hawk at the right thickness and depth as is needed to fill the joints. This way it can just be pushed off the hawk and into the brickwork with less fiddling.
  • To see the different types of finishes or for more details see our pointing brickwork project.

Tools Needed

  • Ladder or scaffolding
  • Joint raker
  • Hammer
  • Chisel
  • Brush
  • Hawk
  • Pointing trowel

Materials needed

Repointing a wall video

Summary: DIY video showing you how to repoint a brick wall, remove old mortar and repoint the brickwork.

Author

The Editorial Team

The Editorial Team at lets-do-diy.com are a team of experts led by Mark Wilson. We have been creating DIY projects, articles, costs guides and product reviews since 2008. For more info see our about page.