When MUST a saddle be installed on a chimney?

The installation of a saddle, also known as a cricket, on a chimney is critical when the chimney is greater than 30 inches wide. A saddle serves as a diversion structure that helps to prevent water from collecting on the back of a chimney, which can lead to water damage or leaks. When chimneys are particularly wide, the risk of water pooling increases, making the installation of a saddle essential to ensure proper drainage.

This requirement is based on standard building practices and codes that account for the physics of water flow. A wider chimney creates greater surface area which can trap rainwater, thus making the saddle necessary to guide that water away and protect the integrity of the chimney and the roof underneath it.

The reasoning for the other options stems from different width thresholds or indicating that installation is unnecessary. However, the crucial point here is that for a chimney that exceeds the 30 inches width mark, having a saddle becomes a key aspect of effective water management in roofing and chimney systems.