What Is Chimney Repointing and When Does It Need Doing?
The chimney stack is one of the most exposed parts of any property. Standing above the roofline, it faces constant wind, rain and frost from every direction while expanding and contracting with changing temperatures. Over time, the mortar between the bricks begins to deteriorate, and repointing is the maintenance that keeps the chimney structurally sound and weatherproof. Although it is one of the most common roofing repairs, it is also one of the most frequently overlooked.
1. What Is Chimney Repointing?
Repointing is the process of removing worn or damaged mortar from between the bricks and replacing it with fresh mortar. This restores the strength of the chimney while preventing water from entering the brickwork. Properly repointed joints improve both the structural integrity and the weather resistance of the entire chimney stack.
On older properties, selecting the correct mortar is essential. Many Victorian and Edwardian homes were built using lime mortar, which allows the brickwork to breathe and move naturally. Replacing it with hard cement mortar can trap moisture inside the bricks, leading to frost damage and the gradual deterioration of the brick faces themselves.
2. Signs Your Chimney Needs Repointing
Several visible signs indicate that repointing may be required. Crumbling or missing mortar joints, gaps between bricks, white salt staining and vegetation growing from the chimney all suggest that moisture is entering the masonry. These problems tend to worsen over time if left untreated.
3. Signs Inside Your Home
Chimney problems are not always visible from outside. Damp patches on chimney breasts, particularly in upstairs bedrooms or after prolonged rainfall, often indicate water entering through failed pointing, damaged flaunching around the chimney pots or defective lead flashing at the base of the stack.
4. What Happens If You Leave It?
Once water penetrates the chimney, deterioration accelerates. Bricks become saturated, frost causes the brick faces to crack and flake away, and the mortar continues to erode. Eventually, sections of the chimney can become unstable, creating a genuine safety risk. Rebuilding a damaged chimney is considerably more expensive than carrying out timely repointing.
The flaunching that secures the chimney pots can also deteriorate over time. Loose pots are particularly hazardous during strong winds and should be repaired before they become a danger.
5. What Does Chimney Repointing Involve?
Safe access is the first priority, which usually means scaffolding or a properly erected access tower. The damaged mortar is carefully raked out to an appropriate depth, the joints are cleaned and fresh mortar is applied to match the age and construction of the property. This restores the weatherproof seal while preserving the character of the original brickwork.
6. Combine Other Chimney Repairs While Access Is Available
Because access equipment represents a significant part of the overall cost, it makes sense to complete other chimney maintenance at the same time. This may include renewing the flaunching around the chimney pots, securing loose pots and inspecting or replacing the lead flashing around the base of the stack, avoiding the need for additional scaffold hire later.
7. When Should You Arrange an Inspection?
If your chimney has not been professionally inspected for several years, or you have noticed crumbling mortar, damp patches or signs of movement, arranging an inspection sooner rather than later can prevent much larger repair bills. Early intervention almost always costs less than waiting until significant structural damage has developed.
Need Your Chimney Checked?
If you're concerned about the condition of your chimney stack, we'll carry out a thorough inspection, provide photographs of any issues we find and explain honestly what needs repairing now and what can safely wait. We offer free quotes, require no deposit and are available seven days a week on 0800 474 8347.