The inquiry
What vertical variation is acceptable?
A masonry professional asked whether the allowable vertical tolerance for concrete masonry and brick construction was 1/8 inch in 10 feet and 1/4 inch in 20 feet.
The questionWhat degree of variation from plumb is permitted, and can the project specifications require a tighter standard?
The expert answer
Vertical erection tolerances for CMU and brick masonry are addressed in TMS 402/602, Building Code Requirements and Specification for Masonry Structures. The response identified TMS 602, Part 3, paragraph 3.3 F.2.b as the applicable provision.
The project specifications still matter
The TMS tolerance establishes a construction baseline, but it may not represent the visual standard expected for every project. An architect may include more stringent tolerances in the project specifications or reference additional guidance from the Brick Industry Association or the concrete masonry industry.
Contractors should review the complete specifications carefully before pricing and construction. A tighter requirement can demand a higher level of workmanship, coordination, and cost than the baseline standard.
Use the mockup to establish expectations
For brick masonry, an approved mockup should be used to establish the project’s expected appearance and workmanship. The mockup gives the owner, architect, contractor, and mason a common visual reference before large areas of masonry are installed.
The response also emphasized an important distinction: there is no single ASTM standard that defines acceptable masonry workmanship. Workmanship expectations come from the applicable code and specification, contract documents, referenced standards and guidance, and the approved mockup.
Key takeaways
TMS 602 establishes baseline erection tolerances for masonry construction.
The cited tolerance is plus or minus 1/4 inch in 10 feet, plus or minus 3/8 inch in 20 feet, with a maximum variation of 1/2 inch.
Project specifications may require tighter tolerances than the masonry standard.
Referenced BIA or concrete masonry guidance can add project-specific workmanship expectations.
An approved brick mockup should establish the agreed visual standard before production work proceeds.
There is no single ASTM standard that defines acceptable masonry workmanship.
Florida Masonry Note
Confirm the edition of TMS 402/602 adopted for the project and compare its requirements with the project specifications before evaluating or pricing the work. When requirements conflict or remain unclear, obtain written direction from the design professional.