How To Remove Efflorescence From Masonry Structures

Efflorescence is a common phenomenon seen on many masonry structures, causing unsightly white stains and blemishes. While it may not pose significant structural risks, it can be representative of deeper issues within a masonry structure and it can also detract from the aesthetic appeal of buildings. Understanding what efflorescence is, its causes, and how to effectively remove it is crucial for maintaining the integrity and beauty of masonry surfaces. In this blog post, Lennox Masonry of Victoria, BC will guide you through how to spot, remove, and prevent efflorescence.

What is Efflorescence?

Efflorescence refers to the migration of soluble salts to the surface of porous materials, where they form a white, powdery deposit upon drying. This deposit is often composed of salts such as calcium carbonate, calcium sulfate, and other minerals dissolved in water. These salts are naturally present in many building materials, including bricks, concrete, and natural stone.

Causes of Efflorescence:

Efflorescence occurs when moisture within the masonry carries dissolved salts to the surface. Several factors contribute to its formation:

• Water Intrusion: The primary cause of efflorescence is moisture infiltration from rain, groundwater, or even water used during construction. As water seeps through porous masonry materials, it dissolves salts present in the substrate.

• Poor Drainage: Inadequate drainage systems around buildings can lead to water pooling against masonry surfaces, increasing the likelihood of efflorescence.

• Temperature Changes: Fluctuations in temperature can affect the rate of evaporation, causing water to migrate through the masonry and deposit salts on the surface as it dries.

• Salt Content in Materials: The type and amount of soluble salts present in the masonry materials themselves can influence the severity of efflorescence.

Removing Efflorescence:

While efflorescence may seem daunting to remove, several methods can effectively eliminate or reduce its appearance:

• Brushing: For light efflorescence, a stiff brush, scrubbing pad or steel brush can be used to physically remove the deposits from the surface. Care should be taken to avoid spreading the salts to unaffected areas.

• Water Rinse: Gentle rinsing with water can help dissolve and wash away efflorescence. However, this method should be used cautiously to avoid further saturating the masonry and exacerbating the issue. However, if your newly constructed chimney or stone wall is already creating efflorescence, it is likely a "new bloom" which is natural for new construction and it is recommended to wash it off as soon as possible.

• Chemical Cleaners: Various commercial cleaners are available specifically designed to dissolve efflorescence salts. These products often contain acids or other chemicals that break down the salts for easier removal. It's essential to follow the manufacturer's instructions carefully and test the cleaner on a small, inconspicuous area first. Exposing brick and certain types of stone to strong chemicals such as muriatic acid can damage them and the mortar surrounding them.

• Poultice Application: A poultice made from absorbent materials such as clay or sawdust mixed with a cleaning solution can be applied to the affected areas. As the poultice dries, it draws out the salts from the masonry. Once dry, the poultice can be removed, taking the efflorescence with it.

Preventing Efflorescence:

While efflorescence can be treated after it appears, preventing its recurrence is equally important:

• Proper Mortar: Using a mortar which is designed to expel excess moisture and salts within a masonry structure is paramount. It's important to utilize mortars which contain lime. Preferably, using a Quicklime or Natural Hydraulic Lime-based mortar would be best when it comes to preventing efflorescence from occurring. To learn more about specific mortar mixtures and their uses, visit our blog post: Masonry & Mortar: A Guide to Different Types of Mortar and Their Uses

• Improved Drainage: Ensure that drainage systems, including gutters, downspouts, and landscaping, are designed to direct water away from masonry structures effectively.

• Selecting Low-Salt Materials: When possible, choose masonry materials with lower salt content to minimize the potential for efflorescence.

Efflorescence is a common occurrence in masonry structures, but understanding its causes and implementing effective removal and prevention methods can help maintain the beauty and integrity of buildings. By addressing water infiltration, improving drainage, using the right type of mortar, and employing appropriate cleaning and sealing techniques, property owners can mitigate the impact of efflorescence and preserve the aesthetics of their masonry surfaces for years to come.

Lennox Masonry of Victoria, BC has been proudly serving both Vancouver Island and the Gulf Islands for over a decade. We are small group of skilled masons with a great deal of passion towards our trade and for improving the communities we live and work in. We extend our gratitude to the lək̓ʷəŋən people for allowing us to share and work on this corner of the garden with them. We are thankful for the residents and businesses of Victoria, BC for supporting us in our endeavors!

If you’re in need of a professional and reliable masonry company for your next project, please contact us today!