Common Paint Problems: Chalking

Minimal chalking cannot be avoided, but chalking can cause serious problems such as staining, paint erosion, and releasing lead.

Chalking is a powdery residue that is created when the "binding agent" in paint begins to deteriorate. This deterioration can be caused by exposure. Rain, snow, sunlight, and even oxygen can cause chalking. Failing to properly prepare the surface before painting or applying paint to a cold, wet, or overly glossy surface can also be problematic. Another culprit is using poor quality, "thin" paint with a high concentration of pigment, or using indoor paint on exterior surfaces.

Some paints are meant to chalk and are considered "self cleaning," so a little chalking is not necessarily a problem. There are also certain paints that are specifically formulated to resist chalking and fading. These paints are good for use in bright sunlight and other extreme weather conditions and will protect the surface to some degree, but no paint can completely prevent chalking.

Chalking on painted surfaces above masonry will run when it rains, dripping the chalk residue onto the masonry. This can often create problematic, tough to remove stains.



Another concern about chalking is that the dust can contain lead. If your home or other surface was painted before 1980, it may very well have been painted with lead based paint. Lead poisoning is a serious problem, especially in small children, so if you believe your paint could contain lead, it is best not to take any chances.

SOLUTIONS:

-If you are concerned about lead, you can hire a home inspector to come in and check things out. He or she will have the paint tested. Or, you can simply purchase a relatively inexpensive home testing kit and do it yourself.

If no lead exists:

-Wash the area thoroughly with mild detergent. Large areas may require a power washer. Rinse well with clean water. You may need to wash twice in order to make sure chalk residue has been removed. After allowing the surface to dry for 12-24 hours, apply a good primer. When the primer is completely dry, apply latex paint.

-You may not need primer if all of the chalk dust has been removed and no residue remains, but priming is the best way to insure that the paint will adhere well.

-You may need two coats of paint, and while this requires more work and is a bit more costly, it is worth it to avoid having to repaint in the near future.

-Always use good quality paint. Compare the concentration of solids in different paints. Liquid (water) evaporates over time, so what you are left with are the solids. "Solids" include additives, binding agents, and pigment. A high concentration of solids usually insures a thicker coat of paint and better coverage. Avoid paints with high concentrations of both water and pigment that contain low percentages of other solids.

-If you are unsure, seek advice from a professional or obtain a recommendation from a customer service representative at your local paint store, home center store, or hardware store.

Serious chalking will erode and thin the layer of paint and as stated can stain other surfaces, so if you have a chalking problem you should treat it immediately.

© High Speed Ventures 2011