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The Ugliest Flower: How much do you know about efflorescence?
by Staff
Efflorescence is a kind of flowering, but it doesn't have roots and it sure doesn't make your yard look good. Test your knowledge of this structural phenomenon with this quiz.

Efflorescence refers to unsightly whitish deposits that can appear on walls or other structural surfaces. What causes it?

  • Insects lay eggs in large clusters on walls, making the surfaces appear patchy or discolored.
  • Salt contained within the structure is drawn out when water escapes through pores in the material, then dries on the surface.
  • Building materials simply deteriorate and become bleached with time.

Efflorescence doesn't occur everywhere. What materials are commonly affected?

  • wood
  • linoleum or other synthetic materials
  • brick, mortar or concrete

Unless it's pouring rain, you probably don't associate wetness or moisture with the walls of your home. So how does water get inside the material they're made of?

  • Concrete that was mixed with too much water can retain some of that water even after the material is technically dry.
  • When you don't turn on the fan when you're in the shower, the moisture seeps into the walls.
  • When porous rocks are used as filler in concrete, they act like sponges and absorb any water they come in contact with.

Preventing efflorescence isn't just a matter of being careful when you're mixing concrete; there are environmental factors that can spur its formation as well. What's one example?

  • owning a swimming pool, which adds just enough moisture to the air to put your masonry at risk
  • light-colored walls, which reflect sunlight that would otherwise dry them out
  • overzealous lawn sprinklers

What's an easy way to tell if your walls contain excess moisture?

  • Place a cup next to the wall you're testing and leave it there overnight. If there's too much moisture in the masonry, the cup will gather water as it seeps out of the wall.
  • Secure a piece of plastic sheeting to the suspect area; if there is excess moisture, condensation will gather under the sheeting.
  • Drill a small hole in one of your walls. If water seeps out, you have a problem.

What characterizes primary efflorescence?

  • Primary efflorescence is usually linked to structural factors like excess water in a mortar mix.
  • The severity of efflorescence is ranked in categores: primary, secondary and tertiary. Primary is the most severe.
  • Primary efflorescence refers to efflorescence located at the bottom of a wall, closest to the foundation of the building.

Efflorescence is ugly, but it doesn't have to be permanent. What's one effective way to remove it?

  • Scrape it off with a paint scraper or a sharp piece of metal.
  • Wash the surface with detergent and water.
  • Pour bleach over the affected area.

What are some risks to keep in mind when removing efflorescence?

  • Sand-blasting can actually leave bits of sand stuck in your walls, giving salt deposits extra surface area to cling onto.
  • Don't overuse chemicals. They can seep into the walls and create a low-level toxic environment.
  • Make sure you don't exacerbate the problem. For instance, excessively vigorous power washing can remove existing efflorescence, but it can also fill your walls with more moisture.

If you're building from scratch, there are a few steps you can take to prevent efflorescence. What is one example?

  • Make sure the sand and gravel used in your concrete or mortar has been washed properly in salt-free water.
  • Keep masonry covered at all times during the building process.
  • Sandblast the material regularly during the building process to create pores and allow water to seep out in advance.

Modern-day homeowners aren't the only ones who struggle with efflorescence. Which famous figure also battled the salty blotches?

  • Frank Lloyd Wright
  • Renoir
  • Michelangelo