If the paint no longer feels tacky or sticky it s completely dried.
Painting chalky siding.
Test old siding paint for lead using a lead test kit.
You can paint it.
If the paint color comes off on your hand the paint is chalking.
This is very important because this is what actually removes the chalk before the primer is put on.
This ensures even coats and will prevent you from missing any spots.
This is called chalking and essentially is the existing paint breaking down from the weather.
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.
If your aluminum siding has developed a chalky residue or is faded stained or just plain the wrong color fear not.
If vertical paint up to down.
If lead is present contact a licensed lead abatement specialist.
It is also important to use a cleaner when powerwashing so that it will actually help remove the chalk along with the pressure.
Rub siding with cloth to check for powdery paint pigment and mildew.
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.
There are several steps in dealing with a chalky surface to ensure a long lasting paint job.
To test the dryness of your paint touch the siding with your finger in an inconspicuous area.
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Cover ground and nearby shrubs with drop cloths.
If your siding is horizontal paint left to right.
Wipe the surface with the palm of your hand.
Some exterior paints such as those used on aluminum siding intentionally chalk for self cleaning.