Height to width relationship
2D1. Where a chimney is not adequately supported by ties or securely restrained in any way, its height if measured from the highest point of intersection with the roof surface, gutter, etc. should not exceed 4.5W, provided the density of the masonry is greater than 1500kg/m3, where:
- W is the least horizontal dimension of the chimney measured at the same point of intersection, and
- H is measured to the top of any chimney pot or other flue terminal (see Diagram 20).
**** Image Diagram 20 Proportions for masonry chimneys