I have some time right now to write this. Normally I’d stay out of it, but I have some time, so here is one structural engineer’s view on the subject of this type of wall, because this battle has raged between architects and engineers for years.
Early in my career I was taught a short hand system for identifying wall types. The wall we see in the OP is from a family of wall assemblies that are loosely known as ‘composite masonry’. That term in itself has specific structural connotations, but for now, call it a composite wall so we can differentiate it from tilt-up, CMU, brick masonry, wood framing, timber, etc, etc.
Here’s the short hand I was taught:
Composite Wall Family:
BC4 - single wythe brick and 4 inch hollow CMU with an unfilled cavity between
BC6 - single wythe brick and 6 inch hollow CMU with an unfilled cavity between
BC8 - single wythe brick and 8 inch hollow CMU with an unfilled cavity between
BG4 - single wythe brick and 4 inch hollow CMU with a fully grouted void between
BG6 - single wythe brick and 6 inch hollow CMU with a fully grouted void between
BG8 - single wythe brick and 8 inch hollow CMU with a fully grouted void between
BV6 - single wythe brick veneer and 6 inch hollow CMU with an air gap between
BV8 - single wythe brick veneer and 8 inch hollow CMU with an air gap between
In each of the above, I add a “t” or “ut” to differentiate the presence of masonry ties or no ties. Also, grout can be replaced with mortar at the contractor’s discretion. And, if a component was unknown, we replaced a letter with a question mark. So if we had no info on grouting, air gaps, or ties, it would look something like B?8?.
So using this short hand, a BG8t is a fully grouted, tied, collar joint wall.
Notice the subtle difference between a BC8t and a BV8t. We made this distinction because a BC8t has specific structural implications, plus water/weather shedding properties, while a BV8t is a wholly water/weather shedding wall. A BG8t also has what we call out-of-plane force-resisting properties, while a BV8t can only transfer out-of-plane forces to the CMU backing component. A BV8t does not add any load resisting capacity to a wall. This is critically important, because a load bearing wall has to resist out-of-plane forces like moment and lateral displacement from things like seismic forces, thermal expansion, wind, shear, etc.
The battle that has raged for years between engineers and architects comes down to the gaps and the grouting. The two G’s. Engineers want to make sure that any load bearing composite wall has 2 inch gaps or greater, and is tied and fully grouted, so that it has out-of-plane force resistance and can be relied upon to be a true load path. Architects either say ungrouted 1 inch gaps are fine, or leave gap and tie details to the contractor to parse out from the building code, assuming that they know this is only supposed to be a water/weather shedding wall assembly. This drives engineers nuts. It’s perfectly ok to have a tied, ungrouted veneer wall with a 1" gap that follows the rules (height, expansion, tie spacing, etc), but the facing masonry is in no way load-bearing. If the assembly isn’t fully grouted, we can only rely on the backing CMU component to be the true load-bearing element.
