What is the maximum height that individual corbels in a masonry chimney should not exceed compared to the masonry unit height?

In masonry construction, particularly in chimneys, corbels are used to provide support for structural elements like mantels or to transition between different support systems. The maximum height of an individual corbel is critical for ensuring stability and preventing structural failure.

The guideline that the maximum height of individual corbels should not exceed one-half of the height of the masonry unit is based on engineering principles that ensure the load is evenly distributed and that the corbel can effectively support any additional weight above it. If a corbel is too high relative to the masonry unit, it could result in an increased risk of failure due to the lever arm effect, where force applied on the corbel can cause it to tip or break away from the wall.

This standard (one-half the height of the masonry unit) allows for adequate support while maintaining structural integrity, avoiding overreaching design that could lead to cracking or collapse. Therefore, choosing this guideline provides the best practice for chimney construction and helps ensure the safety and longevity of the structure.