Division 04 Masonry

Performance Specification Gap in Division 04 Masonry submittals

By Deviation Check Editorial Team. Last reviewed June 1, 2026.

Short answer

A measurable performance property in the submittal (rating, capacity, tolerance, efficiency) does not meet what the spec requires. Default grade in Division 04 Masonry: Blocker.

A measurable performance property in the submittal (rating, capacity, tolerance, efficiency) does not meet what the spec requires. This guide covers how it shows up specifically in Division 04 Masonry submittals.

What to look for in Division 04 Masonry

Key performance parameters in masonry submittals:

  • CMU compressive strength (f'm prism strength, unit strength per ASTM C90: typically 1900-3000 psi for load-bearing)
  • CMU weight class (normal weight ~135 pcf, medium weight ~105-125 pcf, lightweight ~85-105 pcf)
  • CMU moisture content (Type I moisture-controlled vs Type II non-moisture-controlled)
  • Brick compressive strength (psi per ASTM C62, C216, or C652)
  • Brick absorption rate (% per ASTM C67, affects bond and freeze-thaw durability)
  • Brick grade (SW Severe Weathering, MW Moderate Weathering per ASTM C62/C216)
  • Mortar type (M, S, N, O per ASTM C270 - property vs proportion specification)
  • Grout strength (f'g psi at 28 days per ASTM C476)
  • Reinforcing steel grade (Grade 60 per ASTM A615/A706)
  • Stone flexural strength (modulus of rupture per ASTM C99/C880)
  • Stone absorption rate (% per ASTM C97)
  • Fire rating of masonry assembly (hours per UL/WHI listing or calculated per TMS 216)
  • STC rating of masonry assembly
  • Thermal resistance (R-value of insulated masonry assembly)

How severe is it?

Default grade: Blocker. Always a Blocker when the gap touches life-safety or structural performance.

Deviation Check assigns a default per category and escalates or de-escalates based on the spec, always showing its reasoning. See the Division 04 severity rules.

What the PM should do

Treat this as a hold. Do not approve the submittal until the sub resolves it, either by providing the specified product and documentation or by routing an approved substitution or or-equal request. Return the relevant spec passage to the sub as a redline.

Back to the Division 04 Masonry hub, browse all divisions, or start a review.

Frequently asked questions

Which compressive strength and weight class mismatches commonly appear as performance gaps in Division 04 Masonry submittals?

CMU compressive strength is the most frequent gap - ASTM C90 unit strength typically runs 1900 to 3000 psi for load-bearing applications. Weight class mismatches are also common: normal weight runs around 135 pcf, medium weight 105 to 125 pcf, and lightweight 85 to 105 pcf. A product submitted in a lighter class than the spec requires is a Blocker if it touches structural performance.

When does a mortar type or grout strength deviation in Division 04 Masonry become a life-safety Blocker?

Any gap that affects a fire-rated or structural assembly is always a Blocker. Mortar type - M, S, N, or O per ASTM C270 - directly controls shear and compressive capacity. Grout strength is measured as f'g psi at 28 days per ASTM C476. A submitted mortar type weaker than specified, or grout that misses f'g, cannot be accepted until the sub provides conforming product data and test results.

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