Chalky paint is paint that has a white, chalky powder on it that develops as a natural result of weathering. Most paints will become chalky at some point, depending on their exposure to the elements, such as sunshine and water. If chalky paint is not removed, it can eventually cause damage or discolouration to surrounding parts of the house. Before repainting an area with chalking paint, it is necessary to remove all the chalk, along with any dirt and dust on the paint surface.
Fill the bucket with water and a good squirt or two of detergent. There are specialised house prep detergents available, but a strong household detergent is fine.
Put on your face mask, to make sure you don't breathe in any of the chalk residue, dirt or dust from the paint.
Dip the soft-bristled brush into the detergent water and scrub the paint. If the paint is high up, dip a soft-bristled broom into the detergent mixture and scrub.
Scrub the entire surface needing to be repainted, using generous amounts of the soapy water.
Wash the area with the pressurised water; a high-pressure garden hose will work. Make sure all the soapy water is washed away. Let the surface dry.
Run a bare hand over the washed and dried area to determine if there is any chalking left. If there is, there will be a white film on your hand.
Repeat the detergent wash if there is a lot of residue left. Once is usually enough if you scrub well the first time.
Applying a primer after the chalking paint is washed and dried helps the new coat of paint bond with the surface. Chalking occurs most often on exterior painted surfaces, so the wash water will drain into the nearby soil. Use an environmentally friendly, biodegradable detergent to wash the paint.
If your house paint is old, make sure you check to see if it contains lead. If it is lead paint, then it is best to call in a professional to deal with it, as lead poisoning occurs easily and can have serious effects on health.