- As recently as 1985, codes limited a wall's height based on the arbitrary height-to-thickness ratio However, once researchers proved that taller, thinner walls could perform well under vertical and lateral loads, strength-design techniques were introduced to the codes, the height limits got much higher, and designers were free to adjust many factors to get walls as tall and thin as necessary. It didn't take long for designers to realize that they were no longer restricted to a height of 16½ feet for an 8-inch masonry wall. The ability to build masonry walls taller and thinner brings initial cost savings, more interior space and higher vertical clearance. It also has special implications for seismic regions by making it possible to build 8-inch walls where 10-inch walls were constructed using other design techniques. Because thinner walls are lighter, they sustain higher lateral forces, a critical factor in earthquake design.By altering any of the following five factors of the overall design equation, designers can build taller walls: Strength of units
- Amount of rebar in the wall
- Placement of rebar
- Attachment to the foundation or roof.
"Special inspections" are required during the construction of tall slender masonry walls because the strength design method is used. This generally means that a qualified masonry construction inspector is onsite throughout the construction of masonry to assure the client, architect, engineer and building official that the specified mortar, masonry units, grout and rebar were used, that rebar was placed correctly, and proper grouting and consolidation techniques were used. This added cost can pay for itself because it prevents construction delays caused by tardy local-building-department inspectors.