Rinse the area with clear water and allow it to dry. After the surface has dried completely, apply two coats of a good grade of undercoating paint. When the undercoat has thoroughly dried, apply a coat of a top-quality house paint. Under some conditions, two finish coats may be required. This treatment should correct the peeling problem.
Moisture enters the wood siding from the unpainted side.
The absorbing and drying of the moisture causes repeated swelling and shrinking, thus breaking the paint film and causing it to pull away from the wood surface. The first step is locating the source of the moisture. Check the area for leakage from the gutters or eaves of the house. If the flaking paint is near a bathroom or kitchen, the pipes may be sweating or leaking, or excess heat may be causing condensation. You may need to install attic louvers, moisture vents or exhaust fans to correct the build-up of moisture.