A common problem with white paint is its tendency to go yellow. Internal walls, normally painted with emulsion paint, which is oil-based, may yellow with time. Various environmental factors can result in this happening too. Water-based paints such as latex and acrylic paints may also change color, although are less likely to. This article will examine the reasons for white paint yellowing and what to do about it.
Difference Between Oil-Based and Water-Based Paints
As each name applies, oil or water can be used as the liquid solvent base for each type of paint. Both these types have their preferred uses.
1) Oil- Based
Oil-based paints may be natural (they contain linseed oil) or synthetic (containing alkyd oil). These paints are strong and long-lasting and are used mainly for external walls, doors, and kitchen and bathroom cabinets. They are better able to tolerate damp conditions and high-usage areas.
Two types of water-based paint acrylic and latex, commonly known as emulsion paints, are used for different purposes. They are preferred for interior surfaces being almost odorless, quick drying, and low in volatile organic compounds (VOCs).
- Acrylic Paint
This type has more acrylic polymers in it, therefore, is more durable, and resilient and adheres better to surfaces. Kitchen and bathroom cabinets and outdoor furniture are examples of where this paint is worth the extra expense. Some manufacturers refer to it as enamel paint.
- Latex Paint
The advantages of latex paint include that it is cheaper, perfect for large surfaces such as interior walls, is durable, spreads well, and is more eco-friendly. It contains fewer polymers than acrylic paint.
Why White Paint Yellows
Although both white oil-based and to a lesser extent water-based paints may yellow, the reasons are different. Oxidation causes oil-based or alkyd paint to yellow, which is irreversible, whereas the yellowing of water-based paint is due to the evaporation of the water.
Other factors include humidity, impurities in the paint or low-quality pigments, heat from stoves, heaters, and inside geysers, and lack of light or smoke from fireplaces or cigarettes. Oxidation-induced yellowing is unfortunately irreversible.
Water-based paint may become yellow due to a lack of ventilation and light or polyurethane use. If water-based paint is used on wood, it may draw out tannins and turn the white paint yellow. If walls were covered with wallpaper at any stage, residues of glue may be sticking to the surface causing the paint to discolor.
Pet urine can be another cause of white paint going yellow due to its ammonia content.
Yellowing Paint Remedies
As mentioned above, oxidation-induced discoloration is irreversible. The best way to remedy this is to repaint and prime the oil-based paint with a water-based option. However, topcoats of all paints will eventually discolor over a period of time.
Unfortunately, there is no foolproof way of predicting and mitigating color changes in paint ahead of time. White paints are naturally more transparent than most other colors, and unless touch-ups are done periodically, they will eventually fade or go a bit yellow. The more porous the paint, the more likely it will yellow over time.
Suggestions to minimize yellowing include the following:
- Use premium white paint that is durable, self-sealing, and does not require a topcoat if you can.
- A clear topcoat over the white or the use of a clear lacquer preparation, when suitable, may prolong the clean white color.
- Apply the paint with a spray gun for an even finish.
- Add 10-15% of the white paint you are using to the first layer of the topcoat. Follow with two coats of the clear finish.
- Prime with a clear stain-blocking lacquer followed by one coat of light grey before applying the white paint.
- Test on a less visible section of the project to determine any immediate changes in color.
- Always allow the primer to dry overnight before applying the paint.
- If you are refurbishing wooden furniture, be aware of wood stains that may have been used. These may bleed through under white or light-colored paint.
- Ensure that your primer and topcoats are compatible with the paint you are using. Some may react with color changes.
- If your white paint is in an area of high moisture, such as bathrooms and kitchens, consider installing an exhaust fan and/or dehumidifier that suits the size of the room. In the kitchen, this has the added advantage of eliminating grease and other cooking byproducts from settling on your paintwork.
Oil-based sealers, such as polyurethane are especially prone to yellowing, so for best results, you should look for polyacrylic (polycrylic). Do not apply topcoats too thickly as this may also lead to yellowing. Another option is to look for a white gloss finish, which stays whiter for longer on interior surfaces and wood. The advantage of gloss as it is quick drying, in a matter of hours.
Beware of using ammonia-containing products on your white finishes. Ammonia speeds up the yellowing process. Although too much light can turn white finishes yellow, in moderate amounts, sunlight may also reverse the yellowing of oil-based, white-painted furniture.
Other options include: using a mixture of 1 tablespoon of white vinegar in 2 cups of water to wipe down furniture painted white. Alternatively, use a solution of ¼ cup of Trisodium Phosphate (TSP) in 1 gallon of water to wipe off yellow stains.
Even a mild detergent and scrubbing pad may remove residue from glue or other substances from walls or white-painted furniture that is causing discoloration. When installing and painting drywall, ensure that it contains good-quality boards. Some recycled materials can turn yellow when painted white. If all else fails consult a professional.
The yellowing of white paint on walls and furniture is a common occurrence due to oxidation or evaporation. Although there are no completely reversible treatments to solve this problem, without repainting, there are ways to slow down the process.
From the onset, it is wise to use the best quality paint that you can afford, along with a clear topcoat or lacquer for added protection against the effects of the environment. When refurbishing furniture or renovating, be aware of dyes, stains, and other products that may have been used in the past.
Other than commercial products, some household options may be used on small areas of yellowed paint. If you minimize the reasons why white paint yellows, you will have less work to do to remedy the problem.
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