When must a saddle be installed on a chimney?

The correct choice indicates that a saddle must be installed on a chimney when the width exceeds 30 inches. A saddle, also known as a cricket, is a type of structural accessory designed to divert water away from the top of the chimney. It helps prevent water pooling or runoff issues that can lead to leaks or damage to the chimney or the roofing materials surrounding it.

When a chimney is wider than 30 inches, the risk of water accumulation increases, making the installation of a saddle important to ensure proper drainage. This installation is particularly critical in regions with significant precipitation, as it aids in protecting the integrity of the structure. The specified width is a guideline that aligns with best practices in construction and roofing, ensuring that the chimney remains functional and minimizes potential water-related issues.

Other widths mentioned in the other options do not trigger the requirement, aligning with typical building codes that necessitate the saddle only for chimneys that exceed that specified dimension.