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Yellow pollen stains  on exterior stucco from nearby Hibiscus flowers  (C) InspectApedia GCRemove Pollen Stains on Building Exteriors

  • POLLEN STAINS on BUILDINGS - CONTENTS: guide to diagnosing, removing, or preventing stains caused by pollen settling on building exterior surfaces: roofs, walls, siding, trim, walks, drive, stone. How to clean pollen stains off of building surfaces.
  • POST a QUESTION or READ FAQs about how to identify types & causes of stains on building exterior surfaces
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How to remove pollen stains from building walls or other surfaces:

Pollen as a golden, yellow, or other-colored dust settles on building surfaces as well as anything else outdoors: cars, walks, patios. When dry it may be possible to lift off or blow off most pollen grains from a some surfaces but once physically wiped (don't do it) or soaked, the pollen may leave a colored stain that's more difficult to remove. Here we discuss these stains and how pollen stains may be removed or as a last-resort, painted-over.

This article series describes the various stains that appear in or on buildings, listing the stain cause, cure, and methods of prevention. We also include links to references useful in the identification of algae, moss, lichens, and mold.



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How to Remove Pollen Stains on Building Surfaces

Yellow pollen stains  on exterior stucco from nearby Hibiscus flowers  (C) InspectApedia GC

Question: Golden yellow pollen stains on stucco exterior walls

2016/08/13 Colin Frankland said:
I have hard yellow orange stains running from under my flat roofed garage which are almost impossible to remove any ideas how to shift them

2016/08/16 Anonymous said:

1st time ever I have orange stain on my stucco exterior wherever I have hibiscus plants. The stain follows the shape of the plant beside it, so I know it must be from the pollen. Any idea how to remove it? Thanks - Anonymous by comment & by private email

[Click to enlarge any image]

Reply: Tips from removing Hibiscus or other flower pollen stains from walls:

Colin you can use the page top or bottom CONTACT link to send us some photos if you like; we may be able to comment further. It's helpful to have some idea of the stain source and thus its composition.

Gail:

Watch out: Do not brush the surface dry as that will smush the pollen grains into the finish and will probably make the stain worse.

If the area of staining is not large, try some adhesive tape, or masking tape to lift off most of the pollen.

For what remains, spray the stain with a household cleaner or an enzyme-based cleaner. We will discuss these in more detail below.

Before you start, send me some sharp photos of the stains if you can and I may be able to comment further.

Yellow pollen stains  on exterior stucco from nearby Hibiscus flowers  (C) InspectApedia GC

Gail said:
Just sent 3 pics to the editor email. [Click to enlarge any image] shown here - Ed.

Yellow pollen stains  on exterior stucco from nearby Hibiscus flowers  (C) InspectApedia GC

Moderator said:

Gail,

The stains in your photos are certainly in a location and of a color to blame on pollen from the adjacent hibiscus plants.

Once rain or hose-spray smashes the pollen onto the painted surface of the stucco it's no longer a powder that will just lift-off: just as you report.

From what we read in some scholarly articles about the composition of pollen, there are probably some fatty acids that are along with pigmented cells, and along with other chemicals we've not listed, that conspire to both adhere to the wall surface and perhaps to leach into the painted coating. Sporopollenin, a pollen component is insoluble in most common solvents.

Photograph of pollen

The pollen grains shown above, photographed in our laboratory, illustrate the pollen of the Tulip Poplar or Yellow Poplar Tree. See this and more images of pollen under the microscope at POLLEN_PHOTOS.

Cleaners Safe to Use on Pollen Stains on Walls

  1. I would try gentle washing first with a liquid kitchen dish-washing detergent that includes a degreaser feature. Use a sponge or soft bristle brush, wash the surface, then rinse thoroughly.
  2. Safe solvents to try include vinegar, rubbing alcohol, and an enzyme-based household cleaner. Some reports I reviewed claimed success using a shampoo or a kitchen cleaner that included a de-greasing agent.
  3. I read a report of success at removing pollen from building surfaces using a Mr. Clean Magic Eraser produced by Mr. Clean, a Proctor & Gamble company and available at many supermarkets.
  4. I also read one report of successful removal of pollen from car surfaces, including convertible tops using a car cleaning product such as Optimum No-Rinse™ Wash & Shine produced by Optimum Polymer Technologies - a cleaner that does not use soapy surfactants.
  5. What about using a bleaching agent? If your stucco is white or near white you might try a dilute bleach spray or an existing spray product containing bleach, but first have that garden hose handy and wash down the wall quickly enough to avoid bleach run-down discoloration of your paint. I often have success using a milder non-bleaching spray cleaner such as Windex followed by a garden hose spray-off.

Enzyme-based cleaners to try on Pollen Stains on Walls

What to Do when the Safe Easy Cleaners Don't Remove Pollen Stains from Building Surfaces

If you're of a scientific-curiousity-bent and want to fool with solvents:

Shaw (1966) discussed the chemical composition of pollen and thus doubtless its coloring pigments as well.

Though warned-off by Domínguez (1999) I'd try some common household solvents, testing the solvent first on an inconspicuous area of siding so as to determine if the solvent is going to take off paint too - you probably don't want to dissolve the paint if you can avoid it. As organic solvents may work on pollen stains, try an odorless paint thinner - that will most likely not do much to the paint itself. Be sure to read the usage safety warnings.

Paint cleaning chemicals, TSP substitutes, and deck cleaning agents may work but except for the TSP substitute may be a bit harsh on your painted stucco.

More dangerous chemicals like dry cleaning solvent might work but are not so safe to use; acetone would probably work (nail polish remover) but is not so safe to work-with.

Seal & Paint Stained Surfaces That Won't Come Clean

If you cannot remove the stains with safe solvents that don't harm the painted surface (and that's difficult once the pollen has gotten wet), I'd consider a paint-over: on a dry surface, use a lacquer primer-sealer that is likely to have least stain bleed-through, then re-paint the wall area in its original color.

Research on the Composition of Pollen & Pollen Stains on Building Surfaces

Also see POLLEN_PHOTOS at InspectApedia.com

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Continue reading at STAIN DIAGNOSIS on BUILDING EXTERIORS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see STAINS on & in BUILDINGS, CAUSES & CURES - home,

Also see MOLD APPEARANCE - STUFF THAT IS NOT MOLD

Or see STAIN DIAGNOSIS on BUILDING INTERIORS

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POLLEN STAINS on BUILDINGS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING STAINS

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