Have you ever noticed a white powder similar to chalk on your walls? Known as efflorescence, the deposits might look alarming, which the homeowners mistake for mould, fading and structural damage. In this blog, we will break down everything you must know about brick efflorescence- from the causes to its prevention.
What is Brick Efflorescence?
Brick efflorescence is a white, powdery or crystalline deposit that appears on the surface of bricks. Efflorescence refers to the process through which salt migrates to the surface of a porous material, forming a coating of crystalline deposit of salts (also called Calcium Carbonate or limestone). The white, powdery substance is the result of the accumulation and evaporation of moisture on the bricks and other building surfaces. The colour of the brick efflorescence might vary from white to brown, grey or yellowish hues depending on the salt types present. It causes an aesthetic problem with the building.
How Does Efflorescence Occur?
Found on different types of masonry, efflorescence occurs when water or moisture present in the building surfaces dissolves certain salts and migrates to other areas, leaving behind the salty depositions upon evaporation. Efflorescence might occur at different times, from the beginning of your structure’s construction or occur over time.
Experts classify efflorescence into two types:
Primary Efflorescence: It occurs when water comes out on the wall surface with soluble minerals or lime. You might witness primary efflorescence within 72 hours of using building materials, where there is an excess of moisture.
Secondary efflorescence: It occurs when outside sources of water, such as rain or condensation, mix with the concrete and extract salts to the surface of the building materials.
The Major Causes of Brick Efflorescence
Factors responsible for brick efflorescence include the following:
- Presence of Water-Soluble Salts
- Natural Salts: Raw materials used in the manufacturing of bricks and mortar contain natural water-soluble salts, which, when they encounter the moisture in the air, dissolve and crystallize upon evaporation.
- Improper Materials: The use of salty water during construction, impure aggregates, and high-alkali cement often causes deposition of excessive salts.
- Sulphates: Manufacturers use clay for brick manufacturing. The clay contains soluble sulphate salts (such as sodium sulphate, magnesium sulphate, and calcium sulphate), which cause efflorescence when encountering environmental moisture.
- Presence of Moisture
- Weather: Rain, dew, condensation, and moist conditions provide the necessary moisture for efflorescence to develop.
- Groundwater: Groundwater rising through capillary action in the building’s foundation and brickwork is a common source of moisture.
- Construction Water: Excessive water use during construction and improper curing often contribute to the occurrence of efflorescence.
- Leaks: Poor drainage, water leakage through plumbing systems, or damaged gutters and downspouts can introduce moisture into the masonry, increasing efflorescence risk.
- Improper Construction Practices
- Lack of Damp-Proofing: The absence of damp-proof courses (DPCs) or improper installation allows groundwater to rise through capillary action, carrying salts into brickwork.
- Inadequate Joint Filling: Poorly filled or unsealed mortar joints permit water penetration, which can accelerate salt movement and promote efflorescence.
- Improper Curing: Over-curing or under-curing of brick masonry can retain moisture within the walls, leading to salt migration when the structure dries.
- Poor Site Drainage: Improper grading or insufficient surface drainage near the building foundation prolongs contact between brickwork and standing water, increasing the risk of efflorescence.
- Use of Contaminated Materials: Reusing old bricks or unwashed sand containing residual salts can introduce efflorescence sources right from the start of construction.
- Evaporation
- Salt Transport: During a rain or if the building experiences a leakage, the moisture moves through the bricks, dissolving the salts present in them and resulting in efflorescence.
- Salt Deposit: The moisture on dry days evaporates from the building surfaces, leaving behind the dissolved salts in the form of white, crystalline deposits.
- Weather changes: The dropping of temperatures, high humidity and rains dissolve salts, followed by slow evaporation, causing the salts to dry on the masonry surface.
Impact of the Brick Efflorescence on Your Home
Most homeowners question does efflorescence damages brick. Efflorescence might not be structurally harmful; it signals underlying issues affecting masonry over time. While the salt deposits primarily affect your brick’s appearance and finish, prolonged exposure to moisture might reduce coating, adhesion and durability. Addressing the situation promptly preserves your building’s structural integrity and aesthetic appeal.
Potential Damage to Your Home
Efflorescence, being a surface-level condition, prolonged moisture infiltration weakens masonry and concrete over time. The recurring cycle of moisture absorption and salt crystallization often leads to crackling, spalling and reduced material strength. When ignored, these effects will gradually compromise the structural stability and durability.
Possible Health Risks
Efflorescence, consisting of naturally occurring salts, remains harmless and non-toxic. However, constant moisture intrusion creates favourable conditions for mould and mildew growth, affecting indoor air quality and the health of occupants. Addressing the underlying cause ensures a safer and more durable living environment.
How to Remove Efflorescence from Brick?
Are you looking for the best ways to remove efflorescence from your bricks? Then, first, you need to address the underlying moisture issue and proceed with the least invasive cleaning method possible. The best time to carry out the process is when the weather is warm and dry.
Step 1: Identifying and Fixing the Moisture Source
Check for any leaks: Inspect the area for leaky pipes, faulty gutters and improperly installed flushing.
Improve drainage: Ensure that the building has a proper runoff and adjust the surrounding landscape, helping water to flow away from the walls.
Consider rising dampness: Older buildings draw groundwater from the foundation through capillary action. The best way is to switch to more advanced solutions, such as installing a damp-proof course.
Seal hairline cracks: Look for any minor cracks in the mortar or bricks to prevent moisture intrusion.
Step 2: Choosing a Cleaning Method
Method A: Dry Brushing (for light efflorescence)
Often, efflorescence is a fresh, powdery deposit that is water-soluble. You can scrub it off with a stiff, non-metallic brush. Sweep away the loosened salt powder so that it isn’t reabsorbed into the brick later.
Method B: Wet Brushing with Water
If dry brushing isn’t enough, a water-based approach will help in dissolving the salts. The method requires:
- Pre-soaking the brick and scrubbing: Saturate the wall with clean water before applying the cleaning solution. Pre-soaking in water prevents the cleaning agents from penetrating deeply. With a stiff brush and water, clean the surface.
- Rinse thoroughly and dry the surface: Rinse the wall with clean water using a soft-pressure hose. Ensure to apply low pressure, as high pressure will push the salts deep into the bricks. Allow the bricks the dry completely and repeat the process if you notice efflorescence.
Method C: Distilled Vinegar (for stubborn efflorescence)
The acidic nature of the distilled vinegar is effective for stubborn deposits. To use distilled vinegar as a cleaning agent, mix equal parts of vinegar and water in a spray bottle and apply it to the affected areas. Let it set for a few minutes, and with a non-metallic brush, scrub off the deposits. In case of removing efflorescence from old bricks, apply a paste of baking soda after rinsing to neutralise the effect of vinegar.
Preventing Efflorescence: Proactive Measures to Take
During Construction
- Use proper materials: Choose low alkali cement combined with clean and salt-free water for preparing mortar.
- Control moisture: After opening the packaging, store the bricks off the ground and cover them with waterproof sheets.
- Cure concrete properly: Ensure proper curing of the concrete after pouring to prevent efflorescence.
- Incorporate proper drainage: Install damp-proof courses, copings and flashing when designing your building, preventing the moisture from entering the wall.
- Protect new masonry: Cover your new brickwork or structure with tarpaulin to prevent it from rain and moisture absorption.
After Construction
- Manage drainage: Ensure that the landscape slope is away from the building with clear and extended gutters and downspouts at least six feet from the building.
- Apply a sealer: Apply a high-quality and breathable sealer on the bricks to prevent water penetration.
- Ensure regular maintenance: Inspect and repair the cracks, gaps and other damage immediately to prevent moisture entry.
- Improve ventilation: Certain areas, like basements, are prone to moisture buildups and require adequate ventilation.
Brick Efflorescence: Common Mistakes to Avoid
The following are common mistakes to avoid when cleaning brick efflorescence.
- Use of harsh chemicals: Most homeowners use muriatic acid for cleaning, which is strong enough to damage brick surfaces. Hence, test the cleaners on a small patch before cleaning.
- Excessive pressure: Pressure washers often use too much force, which can cause bricks to crack.
- Not rinsing thoroughly: The remains of cleaning solutions and undissolved salts on the bricks’ surface increase the chance of efflorescence.
- Cleaning in hot weather: The hot surface of bricks evaporates the water faster, leading to the rapid reappearance of salt deposits.
Conclusion
While most homeowners fail to consider brick efflorescence seriously, it is an early warning sign of moisture intrusion. A sound understanding of the causes, removal and prevention will help you restore the aesthetic appeal of your structure and maintain its durability. With a combination of best construction practices and latest technologies, Brick & Bolt ensures your home is safe from any hidden issues, such as brick efflorescence.
FAQs
What is the efflorescence test of brick?
The test determines the presence of soluble salts in bricks. To perform the test, experts submerge one end of a brick in a shallow container filled with distilled water for a few days, allowing it to absorb water. Once the brick absorbs water, the brick is dried in a warm, ventilated room to examine the occurrence of powdery residue or efflorescence.
Will the efflorescence stop growing on its own?
An efflorescence generally disappears over time; however, rain and humidity accelerate its removal, dissolving or washing away the salts. Severe efflorescence resulting from persistent moisture issues might not disappear and require proper treatment.
Is damp and efflorescence has a similar effect on my home?
No, efflorescence and damp are not the same and do not affect your home in the same way. Efflorescence indicates an underlying problem, such as a leak or inadequate drainage, which, if left unaddressed, will cause significant loss to the building. If you notice any unusual signs, such as discolouration or increased damp on your building surfaces, seek professional help immediately.
Apoorva H P Achar