BRICK ISSUE GUIDANCE :
CAUSE.
Understanding Lime Run
on Brickwork and Stonework
Lime Run or Lime Staining are common terms used for Calcium Carbonate/Hydroxide deposits that typically emanate from a mortar joint, a gap in-between the mortar joint and the brick, or sometimes a gap or crack in a brick, or from weep holes within the brickwork facade. They are common issues encountered in masonry, particularly with brick and stone structures.
Lime run or staining occurs when soluble lime (calcium hydroxide) or lime-based materials leach out of masonry and deposit on the surface as a white, powdery film. This often happens after rain or when moisture evaporates from the brick or stone, leaving behind deposits, resulting in unsightly discolouration that can detract from the aesthetic appeal of buildings.
It can be initially confused with Efflorescence, as it will often be thick white in appearance, or sometimes a slight greyish colour. An easy way to differentiate between Efflorescence and Lime Run/Staining is that Lime Run will not disappear when brickwork is wet.
It will tend to occur where the brickwork has protracted large quantities of water that follow the same track repeatedly and where excess water continuously flows through a cementitious material. The excess water pushing through the cementitious material can dissolve calcium hydroxide, which is a form of free lime that is created as Portland cement hydrates. This then forms into a solution that finds it’s way to the surface of the brickwork, running down onto the brickwork face and reacting with carbon dioxide in the air to form a crusty calcium deposit.
Often the source of the lime is the Portland cement used in the mortar joint, or it can also come from adjoining concrete or cast stone products, such as dry or wet cast stone copings, cills, heads, and other cast stone feature work sitting alongside brickwork.
Lime run or staining occurs when soluble lime (calcium hydroxide) or lime-based materials leach out of masonry and deposit on the surface as a white, powdery film. This often happens after rain or when moisture evaporates from the brick or stone, leaving behind deposits, resulting in unsightly discolouration that can detract from the aesthetic appeal of buildings.
It can be initially confused with Efflorescence, as it will often be thick white in appearance, or sometimes a slight greyish colour. An easy way to differentiate between Efflorescence and Lime Run/Staining is that Lime Run will not disappear when brickwork is wet.
It will tend to occur where the brickwork has protracted large quantities of water that follow the same track repeatedly and where excess water continuously flows through a cementitious material. The excess water pushing through the cementitious material can dissolve calcium hydroxide, which is a form of free lime that is created as Portland cement hydrates. This then forms into a solution that finds it’s way to the surface of the brickwork, running down onto the brickwork face and reacting with carbon dioxide in the air to form a crusty calcium deposit.
Often the source of the lime is the Portland cement used in the mortar joint, or it can also come from adjoining concrete or cast stone products, such as dry or wet cast stone copings, cills, heads, and other cast stone feature work sitting alongside brickwork.
Severe Efflorescence on a new build development
Here’s a closer look at what lime run and lime staining are, their causes, and how to manage and prevent them:
Key Characteristics of Lime Run:
Causes of Lime Run and Lime Staining
1. Moisture Intrusion:
Water infiltration from rain, leaks, or condensation can cause soluble salts and lime to dissolve and migrate to the surface.
2. Poor Mortar Mix:
A mortar mix with excessive lime content can lead to increased leaching and staining, especially in areas exposed to frequent moisture.
3. Environmental Factors:
High humidity, rainfall, and temperature fluctuations can exacerbate Lime Run and Staining.
4. Inadequate Drainage:
Poor drainage systems can lead to water pooling around brick and stone surfaces, increasing the likelihood of lime migration.
Key Characteristics of Lime Run:
- Appearance: Lime Run appears as streaks or runs of white or grey powdery residue on the surface of bricks and stones. Lime staining can persist for longer periods and may require treatment to remove.
- Location: It commonly occurs on vertical surfaces where water tends to drip or flow, such as walls and facades.
Causes of Lime Run and Lime Staining
1. Moisture Intrusion:
Water infiltration from rain, leaks, or condensation can cause soluble salts and lime to dissolve and migrate to the surface.
2. Poor Mortar Mix:
A mortar mix with excessive lime content can lead to increased leaching and staining, especially in areas exposed to frequent moisture.
3. Environmental Factors:
High humidity, rainfall, and temperature fluctuations can exacerbate Lime Run and Staining.
4. Inadequate Drainage:
Poor drainage systems can lead to water pooling around brick and stone surfaces, increasing the likelihood of lime migration.
CURE.
How to Resolve the Effects of Lime Run
on Brick and Stonework
If Lime Run or Lime Staining has only just appeared, then it may be possible to remove it using water and gentle brushing with a soft bristled brush. Avoid using a stronger bristled brush to not damage the face of the brick and the mortar joints.
If the Lime Run or Lime Staining is more established and has been apparent for longer, then there will be a greater chance that it has formed into a harder crusty calcium deposit that will be more difficult to remove. If so then a brick acid should be used to thoroughly clean the area of brickwork.
Wet the brickwork thoroughly beforehand and apply the relevant brick acid delicately with a soft brush. Repeated cleaning cycles maybe required.
Staining can occur to the underlying brickwork, either from the Lime Staining itself, or from the strength of the brick acid required to remove it, and if so then brick tinting can be used to fully restore the brickwork back to its intended finish.
Here’s how to address lime run and lime staining on brick and stonework:
1. Identify the Source of Moisture:
Before tackling lime run and staining, it’s crucial to identify and address the moisture source:
2. Remove Lime Deposits:
Once you have addressed the moisture source, it’s time to clean the affected areas:
If the Lime Run or Lime Staining is more established and has been apparent for longer, then there will be a greater chance that it has formed into a harder crusty calcium deposit that will be more difficult to remove. If so then a brick acid should be used to thoroughly clean the area of brickwork.
Wet the brickwork thoroughly beforehand and apply the relevant brick acid delicately with a soft brush. Repeated cleaning cycles maybe required.
Staining can occur to the underlying brickwork, either from the Lime Staining itself, or from the strength of the brick acid required to remove it, and if so then brick tinting can be used to fully restore the brickwork back to its intended finish.
Here’s how to address lime run and lime staining on brick and stonework:
1. Identify the Source of Moisture:
Before tackling lime run and staining, it’s crucial to identify and address the moisture source:
- Inspect for Leaks: Check roofs, gutters, downspouts, and plumbing for leaks that may contribute to water infiltration.
- Evaluate Drainage: Ensure that drainage systems are functioning correctly, and that water is directed away from brick and stone surfaces.
- Check Humidity Levels: Monitor indoor humidity, especially in basements or enclosed spaces, as high moisture levels can exacerbate these issues.
2. Remove Lime Deposits:
Once you have addressed the moisture source, it’s time to clean the affected areas:
- Dry Brushing: Start with a soft-bristle brush to remove loose lime deposits. This method is effective for light staining.
- Wet Scrubbing: For more stubborn deposits, dampen the surface slightly before scrubbing. This can help lift the salts without damaging the material.
- Mild Acid Solution: If brushing does not suffice, you can use a diluted solution of muriatic acid (1 part acid to 10 parts water) for tougher stains. Be sure to wear protective gear, and test the solution on a small, inconspicuous area first to prevent damage.
3. Rinse Thoroughly:
After cleaning, it’s essential to rinse the surface with clean water to remove any residual salts and cleaning agents:
4. Apply a Suitable Sealant:
To prevent future occurrences of lime run and staining, consider applying a high-quality sealant:
5. Enhance Ventilation and Moisture Management:
Improving airflow and moisture control can help prevent future issues:
6. Monitor and Maintain:
Regular monitoring and maintenance are key to preventing the recurrence of lime run and staining:
After cleaning, it’s essential to rinse the surface with clean water to remove any residual salts and cleaning agents:
- Use a Hose or Pressure Washer: Rinse thoroughly to ensure all cleaning agents and dissolved salts are washed away. Avoid high pressure if using a pressure washer, as it may damage the masonry.
4. Apply a Suitable Sealant:
To prevent future occurrences of lime run and staining, consider applying a high-quality sealant:
- Choose the Right Sealant: Use a breathable, water-repellent sealant specifically designed for brick and stone. This will help to keep moisture out while allowing any trapped moisture to escape.
- Follow Application Instructions: Ensure the surface is clean and dry before applying the sealant and adhere to the manufacturer’s instructions for best results.
5. Enhance Ventilation and Moisture Management:
Improving airflow and moisture control can help prevent future issues:
- Increase Ventilation: Ensure proper ventilation in enclosed areas like basements to allow moisture to escape. Use exhaust fans or vents as needed.
- Use Dehumidifiers: In areas prone to high humidity, using dehumidifiers can help manage moisture levels effectively.
6. Monitor and Maintain:
Regular monitoring and maintenance are key to preventing the recurrence of lime run and staining:
- Routine Inspections: Periodically check for signs of lime run or staining, especially after heavy rains or in humid conditions. Early detection can prevent more severe issues.
- Prompt Attention to Moisture Issues: If you notice any new moisture problems, address them immediately to prevent further staining.
PREVENTION.
How to Prevent the Effects of Lime Run
on Brickwork and Stonework
Lime Run or Lime Staining can often be caused by inadequate protection of the brickwork during construction on site, which will encourage lime material to be washed from the mortar joints during the build. Brickwork should be covered up during construction and building in wet weather should be avoided wherever possible. Cement and mortar should also be covered up whilst being stored or being mixed on site.
Mortar should be carefully and thoroughly mixed and mortar joints should be fully filled to ensure that excess water does not collect in any air pockets.
Damp Proof Courses and any Damp Proof Membranes should be should be correctly installed and you should avoid any direct water run-off from adjoining floor slabs, etc.
Here are effective strategies to prevent lime run and lime staining on brick and stonework:
1. Choose Quality Materials:
2. Ensure Proper Installation:
3. Enhance Drainage:
Mortar should be carefully and thoroughly mixed and mortar joints should be fully filled to ensure that excess water does not collect in any air pockets.
Damp Proof Courses and any Damp Proof Membranes should be should be correctly installed and you should avoid any direct water run-off from adjoining floor slabs, etc.
Here are effective strategies to prevent lime run and lime staining on brick and stonework:
1. Choose Quality Materials:
- Select Appropriate Mortar: Use a mortar mix with balanced lime content. Overly lime-rich mortars are more prone to leaching. Aim for a mix that provides the necessary strength without excessive lime.
- Use Salt-Free Aggregates: When mixing concrete or mortar, choose aggregates that are low in soluble salts to reduce the risk of staining.
2. Ensure Proper Installation:
- Follow Best Practices: Ensure that brick and stone are installed according to industry standards. Proper installation minimizes gaps that can trap moisture and cause staining.
- Control Moisture During Construction: Limit the use of water during the construction process. Excess water can lead to increased lime migration.
3. Enhance Drainage:
- Install Effective Drainage Systems: Ensure that gutters, downspouts, and drains are functioning correctly to direct water away from the building. Poor drainage can lead to water pooling and increased moisture exposure.
- Grade the Landscape: The landscape around the structure should be graded to slope away from the foundation, preventing water from accumulating near brick and stone surfaces.
4. Implement Moisture Management Strategies:
5. Regular Maintenance:
6. Monitor Environmental Conditions:
7. Consider Professional Advice:
- Seal Vulnerable Areas: Apply a breathable, water-repellent sealant to brick and stone surfaces after installation. This helps to prevent moisture penetration while allowing any trapped moisture to escape.
- Improve Ventilation: In enclosed areas, such as basements, ensure proper ventilation to reduce humidity and moisture buildup.
5. Regular Maintenance:
- Routine Inspections: Regularly check brick and stone surfaces for signs of efflorescence or lime staining. Early detection allows for prompt remediation.
- Cleaning and Maintenance: If you notice lime run or staining, clean the affected areas promptly using a soft brush or a mild cleaning solution. Keeping surfaces clean can help prevent the buildup of lime deposits.
6. Monitor Environmental Conditions:
- Control Humidity Levels: In areas prone to high humidity, consider using dehumidifiers to maintain optimal indoor conditions. This can help prevent moisture from affecting masonry.
- Manage Watering Practices: Be mindful of landscaping practices that involve excessive watering near brick or stone surfaces, as this can lead to increased moisture exposure.
7. Consider Professional Advice:
- Consult Experts: If you’re unsure about the best materials or methods for preventing lime run and staining, consult a masonry professional. They can provide guidance tailored to your specific situation and location.
CONCLUSION.
Prevent and Resolve Lime Run
Lime Run and Lime Staining are common issues in brick and stonework that can detract from the appearance and longevity of your masonry. Understanding their causes and implementing effective management and prevention strategies can help maintain the aesthetic and structural integrity of your buildings. Regular maintenance and prompt attention to moisture issues are key to preserving the beauty of your brick and stone surfaces.
Curing Lime Run and Lime Staining on brick and stonework requires a comprehensive approach that includes addressing moisture sources, removing deposits, and applying preventive measures. By following these steps, you can effectively treat existing lime problems and protect your masonry from future issues.
Preventing Lime Run and Lime Staining on brick and stonework involves a combination of quality materials, proper installation, effective drainage, and regular maintenance. By implementing these strategies, you can protect your masonry from unsightly stains and ensure its longevity. Taking proactive steps not only enhances the aesthetic appeal of your structures but also safeguards them against moisture-related issues in the long term.
If Lime Run and Staining persist despite your efforts, consider consulting a professional for a more in-depth assessment and remediation.
Maintaining the beauty and integrity of your brick and stone structures is essential, and proactive care can make all the difference.
Curing Lime Run and Lime Staining on brick and stonework requires a comprehensive approach that includes addressing moisture sources, removing deposits, and applying preventive measures. By following these steps, you can effectively treat existing lime problems and protect your masonry from future issues.
Preventing Lime Run and Lime Staining on brick and stonework involves a combination of quality materials, proper installation, effective drainage, and regular maintenance. By implementing these strategies, you can protect your masonry from unsightly stains and ensure its longevity. Taking proactive steps not only enhances the aesthetic appeal of your structures but also safeguards them against moisture-related issues in the long term.
If Lime Run and Staining persist despite your efforts, consider consulting a professional for a more in-depth assessment and remediation.
Maintaining the beauty and integrity of your brick and stone structures is essential, and proactive care can make all the difference.