Vinyl Siding Rot Problems

Vinyl siding will not rot, but it can cause rot in the walls behind it.

Vinyl siding is often considered the no-maintenance, most durable form of siding available on the market. Unfortunately, this is not completely true. Vinyl siding can have many problems if it is not installed properly, and the siding is prone to dents and will melt under extreme heat. Vinyl siding can also cause rot of the wood and fibers under the siding if not installed correctly. To prevent this rot, steps should be taken to ensure that the vinyl is installed properly.

Identification

Vinyl rot is usually only uncovered when the vinyl is peeled back from the wall. Rot usually appears as the wood under the vinyl is tearing off or turning black. Mold and mildew is often present on the surface of the wood or insulation beneath the vinyl siding. Sometimes it is possible to see rot forming by unusual buckling along the vinyl siding, or by a constant drip of water, or discoloration along the wall under the bottom of the siding.

Time Frame

It usually takes several years for a leak to start to mold and rot on vinyl siding installed before 1980. Any vinyl installed after 1980 can actually start to rot within just a few short weeks. This is because many modern-day construction workers do not understand the need for installing proper spacing and insulation between the vinyl and the wall. This creates a breeding ground for moisture, which can quickly lead to rot.

Causes

There are two main ways that vinyl can cause rot on walls. One way is with improper spacing between the vinyl and the house. Vinyl siding should be installed with a 1-inch gap between the wall and siding, typically held in place with insulating strips and extending clips. If this gap is too small, moisture can become trapped between the house and the siding, causing it to take much longer to dry. The other way that vinyl can cause rotting is through the connection at the top of the siding where it meets the roof of the house. If the connection at the top of the siding is not sealed properly, moisture from rain and snow will seep between the house and siding.

Prevention

The best way to prevent vinyl from causing rot is to install the siding correctly. Make sure to follow the correct installation procedures recommended by your siding manufacturer. Always have a certified contractor install the siding. It is also important to make sure that the siding is installed with the correct amount of insulation and that all seals are watertight.

Solution

Rot that is already present on the walls is difficult to remove. In most cases the wood must be completely replaced. If the vinyl siding is removed correctly, it can be cleaned and replaced over new wood and insulation. Make sure the vinyl is reinstalled correctly after repairing the damage.

References

• Siding Master: Mold Facts
• JD Home Inspectors: Viny Siding