Frequently Asked Questions

Select a Topic below to expand a list of Frequently Asked Questions.

I. Materials

Concrete Masonry Units (CMU)

I-CMU-1 What is the difference between a “cinder block” and a “concrete block”? (NCMA FAQ 20-14)

I-CMU-2 What happened to the Type I/Type II unit designation in ASTM C90?(NCMA FAQ 16-14)

I-G-1 In accordance with TMS 602-11, cleanouts are not required for grout pours less than or equal to 5 ft-4 in. For grout pours exceeding 5 ft 4 in., can cleanouts be eliminated through a grout demonstration panel?

I-G-2 Is wet-sticking of reinforcement a permitted practice? (NCMA FAQ 02-14)

I-M-1 For an interior “clean room” utilizing glazed masonry unit walls, how should mortar joints be specified to facilitate cleaning?

I-M-2 How is mortar for masonry construction specified?

I-M-3 How do I determine what mortar Type to specify?

I-M-4 When should mortar cube testing be performed?

I-M-5 Is the compressive strength of mortar important?

Reinforcement (R)

I-R-1 Should steel reinforcement (re-bar and joint reinforcement) be galvanized?

I-R-2 Does it matter whether truss-type joint reinforcement or ladder-type joint reinforcement is used in masonry? (TMS FAQ 18.1-1)

I-R-3 Is heavy duty joint reinforcement better than standard joint reinforcement? (TMS FAQ 18.1-2)

I-R-4 Can heavy-duty 3/16-inch joint reinforcement be specified and used in a standard 3/8-inch thick mortar joint?

II. Design

II-E-1 Do concrete masonry walls require continuous insulation? (NCMA FAQ 12-14)

II-E-2 How can concrete masonry assemblies comply with code-mandated air barrier requirements? (NCMA FAQ 03-14)

Flashing (FL)

II-FL-1 In commercial construction, how should the horizontal leg of flashing at the base of the wall be terminated when the masonry veneer extends below grade?

II-F-1 How does one determine the fire resistance rating of an existing, single wythe, hollow concrete masonry wall?

II-F-2 Can the fire resistance rating of an existing, single wythe concrete masonry wall be improved by adding wall finishes?

II-F-3 Can the fire resistance rating of an existing, single wythe, hollow concrete masonry wall be improved by filling the cells?

II-F-4 How does one determine the fire resistance rating of a single wythe concrete masonry wall when only some of the cells are grouted?

Intersecting Walls (I)

II-I-1 When are rigid steel connectors (strap anchors) required for anchoring intersecting masonry walls?

II-I-2 How should intersecting masonry walls be connected?

Movement Control (MC)

II-MC-1 What are masonry movement joints?

II-MC-2 Who is responsible for determining the locations of masonry movement joints?

II-MC-3 How does an engineer determine the location of masonry movement joints in a structural masonry wall?

Reinforcement (R)

II-R-1 When should ladder-type joint reinforcement be used and when should truss-type joint reinforcement be used?

II-S-1 Why did the 2013 TMS 402 standard introduce a design check for web shear stresses? (NCMA FAQ 26-16)

Stack Bond (SB)

II-SB-1 Are there Code requirements for joint reinforcement in masonry laid in stack bond?

II-SB-2 Are there Code requirements, in addition to horizontal reinforcement, for masonry laid in stack bond?

II-V-1 Will a concrete masonry veneer require horizontal joint reinforcement?

II-V-2 Are steel shelf angles required to support masonry veneer with block backup?

II-V-3 What are the industry recommendations on recesses in masonry veneer?

II-V-4 What are the industry recommendations for banding dissimilar masonry veneer materials?

III. Construction

Grouting (GG)

III-GG-1 In accordance with TMS 602-11, cleanouts are not required for grout pours less than or equal to 5 ft-4 in. For grout pours exceeding 5 ft 4 in., can cleanouts be eliminated through a grout demonstration panel?

III-GG-2 Is wet-sticking of reinforcement a permitted practice? (NCMA FAQ 02-14)

Moisture Management (MM)

III-MM-1 Are RILEM Tubes an Effective Method of Evaluating the Water Repellent Characteristics of CMU? (NCMA FAQ 25-15)

Reinforcement (R)

III-R-1 Can horizontal joint reinforcement be field fabricated to create 90 degree corners?

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