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Efflorescence is a common issue that brick and concrete buildings can face. Although it ruins the aesthetic appeal of a building, it is easy to fix, so don’t panic if you notice it on the exterior of your home!

Continue reading to find out more about efflorescence and render.

What is Efflorescence?

Efflorescence is a deposit of salts that presents as a white chalk-like substance. It is found on brick, cement and tiled buildings, and mortar, plaster and rendered surfaces. Efflorescence is formed after the moisture evaporates from the surface of the rendering, leaving salt deposits behind.

Although it is unsightly, it can be easily fixed, although, in rare cases, it can signify a more serious problem.

What is the Cause of Efflorescence?

Multiple factors can contribute to the cause of efflorescence. These factors can include:

  • Moisture: Moisture from rain and humidity can cause efflorescence to form.
  • Water quality: If hard water is used during construction, it can lead to higher chances of efflorescence forming on a building. If soft water is used, there is a lower risk of efflorescence.
  • Soluble salts: Cement is made up of different soluble salts, including sodium, magnesium and calcium. When water and cement come into contact with one another, the water dissolves these salts, which can then lead to the salts crystallising on the surface of the building.
  • Temperature changes: Temperature fluctuations can begin the crystallisation process.
  • Improper mixing and curing: If the cement is mixed improperly or cured inadequately, it can result in efflorescence.

What Are the Signs of Efflorescence?

The important signs of efflorescence to look out for include:

  • Colour changes: If the colour or appearance of your render changes, like becoming faded, it can be a sign of efflorescence.
  • White streaks: The most common signs of efflorescence are white, chalky spots or streaks that can be found on the surface of a building.
  • Texture changes: The texture of your render can become gritty or rough.
  • Blistering or bubbling: Efflorescence can cause the render to blister or bubble because of the moisture and salt that is trapped beneath the surface.
  • Cracking or spalling: In some rare cases, efflorescence can lead to cracking or spalling, which is a sign of a more serious underlying problem that should not be ignored.

Why is Efflorescence a Problem?

Although efflorescence is mainly a cosmetic issue, if left untreated, it can damage the pores of the masonry and cause the structure to become water-damaged.
If the efflorescence is not treated, it can cause the concrete to split, tiles to become dislodged and rust to form.

Preventing Efflorescence

Efflorescence can be prevented by:

  • Quality materials: Make sure you select high-quality cement and other construction materials for your building and rendering project.
  • Minimise moisture: Keep the cement rendering as dry as possible during and after construction.
  • Good drainage: It’s important to have proper drainage systems around your building to help stop moisture from coming into contact with your cement rendering.
  • Clean water: Clean, low-mineral content is best to use for mixing cement. Avoid using that has high levels of dissolved salts.
  • Proper mixing and curing: Follow the manufacturer’s instructions to ensure that the cement is mixed correctly and the curing process is successful.
  • Seal the surface: Applying a sealer to the render can help prevent moisture from entering the structure’s surface.

How to Treat/Remove Efflorescence

The most effective way to treat and remove efflorescence includes:

  • Scrubbing: Use a stiff brush to scrub the surface gently to remove any loose efflorescence.
  • Water: After brushing the surface with a stiff brush, rinse the surface of the building to remove any residue.
  • Pressure washing: A low-pressure washer can more effectively remove stubborn efflorescence.
  • Chemical cleaners: A chemical detergent that is specially made to remove efflorescence sometimes works best.
  • Reseal the render: After the efflorescence is removed, consider resealing the render to stop moisture from entering the building surface and preventing efflorescence from forming again.
  • Call the professionals: If the efflorescence keeps returning, it is best to call in the professionals who can diagnose any underlying issues.

Removal Tips to Remember

Before removing the efflorescence, check that there are no underlying problems with the structure itself. Otherwise, the efflorescence may keep returning.

Always wear protective gear when removing efflorescence from the building and protect the surrounding areas.

Add damp sand when using a stiff brush to add extra abrasiveness.

There are liquid formulas that are specially made to dissolve hardened efflorescence.

If you think you have efflorescence and want to make sure that you have no underlying structural issues, contact Sydney Cement Rendering today! We take pride in being Sydney’s trusted rendering experts and providing our customers with the highest quality rendering services. Contact us at 0402 704 984 or visit our website: to find out more about what we offer!