If the paint color comes off on your hand the paint is chalking.
Painting chalky siding.
As a rule of thumb paint takes two hours to dry.
Rub siding with cloth to check for powdery paint pigment and mildew.
It is also important to use a cleaner when powerwashing so that it will actually help remove the chalk along with the pressure.
This is very important because this is what actually removes the chalk before the primer is put on.
This oxidation that occurs on aluminum siding results in the build up of a chalk like substance on the siding itself which can easily be seen by wiping your hand across the aluminum.
Some exterior paints such as those used on aluminum siding intentionally chalk for self cleaning.
If your aluminum siding has developed a chalky residue or is faded stained or just plain the wrong color fear not.
Test old siding paint for lead using a lead test kit.
There are several steps in dealing with a chalky surface to ensure a long lasting paint job.
Here s how to prepare the surface and choose your paint.
Scrub off the chalk with a strong solution of water and spic and span or tsp detergent or a nonphosphate tsp alternative.
By the diy experts of the family handyman magazine.
If the paint no longer feels tacky or sticky it s completely dried.
If lead is present contact a licensed lead abatement specialist.
This ensures even coats and will prevent you from missing any spots.
To test the dryness of your paint touch the siding with your finger in an inconspicuous area.
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If your siding is horizontal paint left to right.
Wipe the surface with the palm of your hand.
This is called chalking and essentially is the existing paint breaking down from the weather.
Cover ground and nearby shrubs with drop cloths.