Concrete masonry units
Standard CMU is 8 by 8 by 16 inches nominal. They come in various weights and strengths and are used for foundation stem walls, retaining walls, and entire buildings. Cells are filled with grout and rebar where structural strength is needed.
Brick
Brick is fired clay. Modular brick is sized so that three courses plus three mortar joints equal eight inches. Brick is durable and attractive but heavy and slow to lay. In California seismic zones, brick veneer must be tied back to the structure with corrugated metal ties.
Mortar
Mortar is cement, lime, sand, and water. Type S is the most common structural mortar at about 1,800 psi. Type N is softer, used for above-grade non-load-bearing work. Match the mortar to the masonry unit; mortar should be slightly weaker than the unit so cracks form in the joints, not the units.
Mini-quiz
Attempt 1 · 3 questions
Check your understanding. Passing is 70% — but you can keep going to the next lesson either way.
Question 1
Based on "Concrete masonry units", which statement is correct?
Question 2
Based on "Mortar", which statement is correct?
Question 3
Based on "Mortar", which statement is correct?