Why Does Siding Get Chalky?

Why Does Siding Get Chalky?


Have you ever leaned up on a house and when you came off of it, either from you noticing or someone else noticing, the back of your shirt was covered with a mysterious, white substance?


That substance is chalk.


I remember growing up, this happened all the time to us as we were playing games and leaning up against houses, usually it was one of us kids seeing it on someone else and pointing it out.


Fast forward to adulthood and doing what I do, I see this type of occurrence happen frequently as I am constantly rubbing my hands on people’s homes to check for this phenomena.



So then, why does this happen?


Great question!



Chalking happens on vinyl siding, on aluminum siding, and on siding that has been painted.


Oxidation occurring during some type of damp weather is the culprit.


Oxidation is referring to a reaction that happens when something, somehow becomes chemically combined with oxygen.


When these kinds of reactions take place with the correct amount of moisture, it leaves behind this chalky residue on these various styles of surfaces.



Over time, this residue can build up.

The more the residue builds up, the more difficult it is to remove.

Chalking can be extraordinarily frustrating when working to remove it.

In fact, it may take multiple efforts to remove the chalk.



Hand washing with a scrub brush or dual-sided sponge could definitely do the trick.



Powerwashing can also work if done safely and correctly.



When washing, my suggestion would be to use some type of detergent to assist you.


Because mildew is many times intermingled with chalkiness when we are washing someone’s home, we typically use a diluted chlorine solution.



If getting rid of the chalk is the main objective,

I would suggest a degreasing, dish detergent


(though I have heard of some folks using laundry detergent).



Although I am admittedly very bias, the best way that I have found to neutralize the chalk from returning, is by painting the surface that it is forming on…





(Yes, if it is forming on vinyl,

believe it or not,

vinyl can be painted).





This certainly is not a guarantee that the chalk will not return in one way, shape, or form.


This does, however, totally refresh the surface and, with today’s technology being what it is, it is tougher for chalk to form on the surfaces of the highest quality exterior finishes than it ever has been before.


It all comes down to how much the chalkiness bothers you in combination with how much effort you want to put into making sure that the chalkiness is as limited as possible in the future from having to be addressed.


If the chalkiness is just something that “exists” and is merely a once in a while type of nuisance to you, you may not even want to do anything with it.


But if the chalkiness is something that is constantly somehow getting on people’s clothes and bodies and has become more than annoying, you may want to look at, minimally, attempting to wash it off and, on a grander scale, perhaps even look into getting things painted to limit the chalky presence as much as possible going forward.




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