R606.4.3

Section R606.4.3 is titled 'Change in thickness' and covers requirements for wall construction. The requirement for hollow masonry units which decrease in thickness from the courses below to have a supporting course of solid masonry, hollow masonry filled with mortar or grout, or other special design and construction is established. The purpose of this section is to prevent structural failure.

The model shows a partial hollow block wall section with a decreased thickness block supported by a course of hollow block filled with grout.