What is the minimum projection allowed for corbelled walls beyond the face of the wall in relation to wall thickness?

The minimum projection allowed for corbelled walls beyond the face of the wall is one half of the wall thickness. This requirement ensures structural stability and safety, as a projection that is too small may not adequately support the loads placed on the corbelled feature.

In corbelled construction, where courses of masonry are laid out to project beyond the vertical face of the wall, it is essential to maintain a balance between aesthetics and structural integrity. A projection that is one half of the wall thickness helps in distributing the weight effectively and prevents potential failure or collapse of the corbelled portion. The code emphasizes these dimensions to ensure that any decorative features added to the walls do not compromise their overall strength and durability.

The other options suggest smaller or larger ratios that either do not provide sufficient support or exceed reasonable limits for typical construction practices, which would contravene the safety priorities established in the building code. Thus, one half of the wall thickness is the minimum projection deemed appropriate for ensuring both the functionality and safety of corbelled walls.