Moisture

• Moisture is often the culprit when it comes to peeling paint. If moisture gets behind the siding it will push the paint off of the front, causing unsightly peeling. The problem can be fixed, though, depending on where the paint is peeling. If the peeling paint is limited to the area around bathrooms, it means that the moisture is being drawn through the walls and you need an exhaust fan in the bathroom. Peeling paint at the top of walls only indicate that your gutters or roof are leaking and need to be fixed, while peeling paint along an entire wall might mean that the siding needs more ventilation to prevent moisture buildup.
  
  

Oil Paint

• A common cause for peeling paint on older homes is a reaction between older oil paint and new latex paint. Many old homes were painted with multiple layers of oil-based paint, which oxidizes and cracks over time. Many homeowners choose a modern latex paint to repaint the home. However, the house must be completely stripped down to the bare wood before painting. If latex paint is added over oil paint, when the latex paint expands in the heat, it will pull the oil paint off of the wood, which causes peeling and damage.
  
  

Poor Preparation

• If you're repainting a house that was originally painted with latex paint, poor preparation can cause the new paint to peel. Painting over paint that is already peeling or flaking will only create an unsightly surface that is more likely to peel. Before painting, scrape any flaking paint and use a pressure washer to remove large sections of old paint. Sand the surface, and use a high quality primer to prepare the surface for the new paint. Some professional painters add a paint-compatible, water repelling preservative before priming bare wood to prevent moisture from damaging the wood and the paint.
  
  

Time

• Exterior paint doesn't last forever, and unfortunately, just the simple passage of time and exposure to the elements can cause paint to peel. If you live in an area that experiences temperature extremes, that can hasten the breakdown of the paint. Proper preparation, applying paint in multiple thin coats instead of one thick coat and addressing any moisture issues can help keep the paint looking new longer. Always follow the manufacturer's directions for using the paint as well; painting when it is too cold or hot can affect the finish of the paint and hasten it's breakdown.