If you own a historic property and notice the face of your stone or brickwork flaking, peeling or crumbling off, you could be seeing the destructive signs of spalling. This isn’t just an aesthetic issue. Rather, it’s a critical indicator that your building is struggling to manage moisture, often due to improper maintenance.

At K. Blythin, we specialise in preserving the integrity and beauty of historic buildings across Chester and the Northwest. So trust us, understanding what causes spalling is the first step toward saving your masonry.

So, What Exactly is Spalling?

‘Spalling’ is the term used to describe the deterioration of masonry where the surface material breaks away from the main body of the stone or brick. It often looks like the outer layer is literally being pushed off in thin flakes or large chunks.

This damage is nearly always caused by moisture trapped inside the wall being forced to escape through the masonry itself, rather than through the joints as intended.

The Real Culprit: Cement Mortar

While spalling can sometimes be caused by freeze-thaw cycles on poor-quality stone, the overwhelming cause in historic buildings is the use of hard, non-breathable cement mortar for pointing or repairs. So how does this happen:

1. Trapped Moisture: Historic walls were designed to breathe, allowing moisture to evaporate safely through the soft, porous lime mortar joints.

2. Cement Seals the Wall: When cement is used, it acts like a rigid, waterproof seal. Thus, it prevents moisture from escaping through the joints.

3. Hydrostatic Pressure: The trapped moisture inside the wall is then forced to migrate outwards through the path of least resistance, which would be the softer brick or stone. As it evaporates, it leaves behind dissolved salts, which crystallise beneath the surface.

4. Pressure Builds: These expanding salt crystals generate immense internal pressure, which would then physically push the outer face of the masonry off. This process is spalling, and it is irreversible damage to your historic fabric.

The Solution: Restoring Breathability

Now that you understand what the issue is, the only long-term remedy for a wall suffering from spalling is to remove the inappropriate cement and reinstate the breathable lime mortar system.

Our expert approach at K. Blythin focuses on:

• Careful Removal: Meticulously removing all non-breathable cement from the joints without causing further damage to the masonry.
  
• Bespoke Lime Mixes: Repointing with a carefully formulated, traditional lime mortar that perfectly matches the aesthetics and function of the original material. You can have peace of mind knowing this mortar allows the wall to breathe again.
  
• Preventative Durability: By restoring the breathability of the wall, we eliminate the primary cause of spalling, ensuring the longevity and structural health of your historic property for generations to come.

So if you are seeing signs of crumbling or flaking stone or brick, act fast. 

By delaying the repair, it only increases the cost and the amount of damage to your precious historic building. And professional lime pointing is an investment in preservation that guarantees your masonry can finally breathe and retain its value for years to come.

Who is K. Blythin?

K. Blythin Brick & Stonework Ltd is an experienced, family-run business from Chester with over 60 years of combined experience in the brick and stone-working trade. 

We handle all manner of brickwork and stonework from lime mortar pointing & brick laying to paving & drystone walls. Rest assured, we’re qualified in heritage practices, so this means we can assist with restoration and improvements to listed properties and buildings of historical importance. So give us a call and let an expert guarantee the longevity of your historic structure.