Why Is My Chimney Turning White?

Category: Chimney

You might not have given the white residue on your brick chimney much notice. However, this white staining, known as chimney efflorescence, can cause serious issues if ignored.

Although you could assume that it is simply a natural aging process for chimneys, this white residue is a sign of a major issue. Homeowners give this issue little thought because it affects many chimneys. The condition is more than just an eyesore; it indicates that the chimney is letting water through the masonry, which will lead to structural damage and other issues.

inspecting a chimney

What is Efflorescence?

The term "efflorescence" may not be recognizable to you. Still, if you own a home or other structure, it is crucial to learn about it as it is one of the most frequent masonry stains that can appear on masonry and historic restoration projects. Efflorescence is the name for crystalline salt deposits on porous building surfaces. The phrase has French roots and means "to flower," indicating the "bloom" of salt on the surface. It is also sometimes called "whiskers." However, the translation may seem lovely, and efflorescence on your stone or basement walls signifies more significant issues.

Efflorescence is a white powdered or crystallized substance in brick, block, or stone construction. The substance develops as a result of surplus water in the building evaporating and leaving behind salt deposits that, over time, take on a fluffy or fuzzy shape and cover the stone's surface.

Although the salt deposits are a cosmetic issue and will not harm the structure, they are a telltale sign of excess water and leaking inside the building. In addition, efflorescence develops when the chimney structure is cracked, improperly sealed, or lacking a cap or other sealant.

Problems Caused Due to Efflorescence

Rainwater can enter the brick or stone walls because of this. Water disperses salt ions naturally present in the masonry as it passes through the wall. The salt residue on the surface will then be left behind as the water evaporates through the exterior wall. These salt deposits cause white discoloration on chimneys. The apparent salt residue is a sure warning that water is leaking into the stone building and, if ignored, can result in significant structural damage. Compared to other stains, the white salt on the surface is relatively simple to remove, but further investigation is needed to identify the cause of the water leak and avoid structural damage.

What is Present in Efflorescence?

Efflorescence starts with salt. Salts are found in the soil and in building supplies such as sand, clay, cement, lime, brick, mortar, and mortar, as well as in admixtures and backing materials.

Efflorescence is often white, but it can also be yellow or brown depending on the salt and other chemicals present. Common salts include vanadyl sulfate, calcium carbonate, sodium carbonate, manganese oxide, and sodium sulfate.

The next ingredient is water. Water used in cement and mortar mixtures during construction can initiate the process by dissolving salts in any building materials it comes into contact with. For example, bricks are capable of absorbing water from snowmelt and rain. Additionally, water can enter brick-and-mortar structures through cracks, which can develop for several reasons and frequently go unreported by homeowners until extensive damage has been done. Rain, snow, sprinklers, fissures, gaps, and the earth all contain water. Salts are dissolved by water and are carried to the top of cement or brick foundations. Efflorescence is the residue of salts that are left behind as water evaporates.

What Causes the Chimney to Turn White?

Typically, chimney efflorescence appears seven years after switching to a more efficient furnace that utilizes the same size chimney. As a result of moisture entering the chimney and dissolving the soluble salts present naturally in the brickwork and mortar, efflorescence builds up on masonry structures. When the salty liquid is exposed to the air, it evaporates and leaves a salty residue on the chimney's exterior.

white chimney on a red roof

Chimney efflorescence typically occurs when gas appliances, such as furnaces and water heaters, are used and vented into masonry chimneys. High-efficiency oil furnaces exhibit it too. The flu size should decrease when replacing an old furnace with a more effective one. If it is not lowered, the condensation inside the chimney will either get better or worse. Because a high-efficiency furnace has a lower stack temperature entering the chimney, the exhaust flue gases, or the combustion products, are cooler and nearer the dew point when condensation occurs.

Preventing Efflorescence Pre-Construction and Post-Construction

Preventing efflorescence on the brick before or after construction will be more cost- and time-efficient in the long run than removing it. It all comes down to making careful selections and separating building materials from salt and water sources when it comes to new construction. Here are some suggestions for avoiding efflorescence during building.

Storage Separation

Masonry supplies should be kept off the ground and covered with waterproof sheeting, stopping them from absorbing too much salt or water.

Changes to The Architecture

Ensure eaves, overhangs, and flashing are included in the construction plans to lessen the possibility that water will infiltrate the wall from above. This change will also help prevent your chimney from turning white.

Landscaping Changes

Ensure the landscaping plans include sufficient runoff zones that divert water away from brickwork. In addition, you should install sprinkler systems, so water is not directed at the building or a wall. This change will also help prevent your chimney from turning white.

Capillary Rupture

Put vapor barrier sheeting between the ground and the masonry building, stopping salt from absorbing and water from entering.

Combined Grout

The movement of water and salts between bricks, blocks, or stones can be slowed down by mechanical vibration and tight mortar joints, which can eliminate gaps in the grout and reduce porosity. By doing this you will help prevent your chimney from turning white.

Cement Additives

Certain grout admixtures can increase grout flow, decrease water content, and minimize porosity.

Coating Sealant (Water Repellent)

Application of a hydrophobic sealant as the last step, following mortar tooling and final clean-down, prevents exterior absorption of water from rain and snow.

Adequate Drainage

Make sure bedding material and grading allow for sufficient drainage while putting pavers. Permeable geotextiles can stop the earth from absorbing salt.

How to Remove Efflorescence Without Using Chemicals?

Brickwork with surface efflorescence is unattractive but easily fixed. You can remove the brick, block, concrete, or paver efflorescence in three ways. First, when the weather is warm and dry, you can remove efflorescence most effectively.

Rigid Brush

Use a firm brush on some smooth surfaces. Since efflorescence is dry and powdery, it is easily cleaned with a brush. To protect your lungs, put on a dust mask.

Water Rinse

On other surfaces, using a power washer or garden hose to rinse can dissolve efflorescence and cause it to run off. Use the widest-angle tip available on your pressure washer to get the job done without scratching the surface. However, as the substrate dries, the rinsing technique may bring more salts to the surface, necessitating a second rinse or brushing.

Reviewing the Effects of Efflorescence

It is crucial to remember that efflorescence is a perfectly typical by-product of masonry construction because of the materials' salts, even when appropriate measures are taken to isolate masonry from water and salt sources. You should remove initial efflorescence blooms, and they should not come back. After the salts in the pavers have gone, efflorescence on them will finally stop.

On the other hand, persistent efflorescence could be a sign of water intrusion that needs to be fixed immediately to prevent long-term harm to the building.

Vertical has been in the chimney care business for over 35 years, and we have devoted our time and energy to bring safety to your home. We have spent all 35 years making sure we give our customers the best possible service. Take your chimney to a higher standard with Vertical and contact us today to get a free quote!

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