(604) 761-5640
Back to Blog

What Is Roof Efflorescence?

June 26, 2020 by ROTban Services Corp. rotbanjun2020

Roof efflorescence is an interesting phenomenon where a roof may look like it has tiny white dots or patches of white on it. Efflorescence can occur on surfaces other than roofs, as well.

What is efflorescence?

Efflorescence is when calcium hydroxide, a compound found in concrete products, reacts with carbon dioxide in the atmosphere to create calcium carbonate crystals. The little white dots that you may see are calcium carbonate crystals sitting on the surface of the roof in the case of roof efflorescence.

When building materials contain concrete, small amounts of the calcium hydroxide in the concrete migrate to the surface of the material. That’s why and how the calcium hydroxide can react with the carbon dioxide in air.

The crystals sparkle, which is why it’s called “efflorescence”. The calcium carbonate fluoresces.

Is roof efflorescence harmful?

No, it is not. These little crystals may be formed at the beginning of the service life of certain types of outdoor concrete materials such as roofing tiles that contain concrete. The calcium carbonate usually disappears over time.

The roof efflorescence does not affect the integrity of the building materials, however it may be unsightly. On roofs, some areas may be affected more than others, and there may be patches of efflorescence. The efflorescence is not always evenly spread out.

Roof efflorescence is something that we treat successfully on a regular basis with our product. Our product will prevent the appearance of roof efflorescence. If you are concerned about potential roof efflorescence, and the unsightliness that it causes please contact us because we can help.

Since 1998, ROTbanTM Ultra Cleaning Corp has been removing moss, algae, and stains from roofs, building exteriors, and landscape structures for commercial and residential customers. ROTbanTM operates throughout the Lower Mainland from West Vancouver to Hope.

If you have any questions about this article or would to schedule an appointment with us, please call (604) 761-5640 or email us at info@rotban.ca.