Repointing a chimney: An expert step-by-step guide

Close up of poorly pointed chimney
(Image credit: Chris Longhurst)

Why would you need to think about repointing a chimney? Because they are constantly exposed to the elements such as wind, rain and frost and over the years this will take its toll on the mortar holding the components of the chimney together.

The mortar will start to break down and make the chimney unsafe and dangerous to passers by. The brick will start to spall – this is where moisture in the brick freezes, the frost expands and when it thaws it contracts – which will, in time, cause the face of the brick to blow off. Repointing will help stop this happening.

But it is not just the weather conditions that can play havoc with the mortar in your chimney. Sulphur produced by the burning of wood and coal can also build up on the inside of the flue which attacks the mortar causing it to break down, leaving the chimney's strength compromised.

Once your chimney is safe, watertight and ready for the next 30+ years you can carry out internal work such as removing a chimney breast without any worries of what might happen above. 

Here, we provide a step-by-step guide to repointing chimneys, whether you're a competent DIYer or simply want to understand the process before hiring a tradesperson to undertake the task for you.

Chris Longhurst

Chris is a full-time Staffordshire builder who has more than 40 years of experience in the construction industry. He has his own YouTube channel that has had over 19 million views and 45K subscribers and provides how-to videos to aid builders and DIYers undertaking building tasks around the home.

With contributions from