Hardboard Siding Is Leaking With Dark Streaks

Hardboard Siding

• Hardboard siding consists of a type of wood-based composite that resembles plywood. This type of siding usually comes in individual pieces or large sheets. As with other types of sidings, correctly overlapping the boards helps direct the flow of water away from the walls and encourages proper drainage. The durable finish on the surface of your hardboard siding helps seal out moisture. This type of siding has a tendency to fail under extreme weather conditions, often causing buckling and leaking.

Leakage

• Gaps between the siding boards can allow water to enter and run beneath the boards. Excessive moisture can cause mold and mildew to form under the siding, causing the dripping water to take on a dark color and creating discolored streaks along the lower pieces of siding. Holes in damaged siding can direct the flow of rainwater onto the wood that forms your exterior walls, eventually causing water damage to the inside of your home.

Repairs

• The first step when repairing leaking siding is to determine where the water enters. Look for holes, cracks and gaps. Repair any small holes by filling them with a paintable waterproof caulking. Paint over the dried caulking with a high-quality exterior latex paint. Remove and replace any buckled, cracked or damaged pieces of hardboard siding, following the installation procedures recommended by the manufacturer. Clean the discolored boards with a liquid disinfectant labeled for use in controlling mold and mildew.

Considerations

• Making minor repairs can help decrease the appearance of water stains and leakage, although extensive damage may require the complete removal of your hardboard siding. Replacing this material with a non-porous type of siding, such as aluminum, vinyl or fiber-cement siding, may help reduce the possibility of new siding leaks, especially in climates with heavy rainfall, strong winds, and high levels of humidity.