Masonry Activity Hazard Analysis
Published:
Masonry construction on USACE and DoD projects presents a combination of structural, ergonomic, respiratory, and fall hazards that require careful analysis through the Activity Hazard Analysis process. EM 385-1-1 Section 24.D addresses masonry-specific requirements including limited access zones, wall bracing, and scaffold load considerations unique to masonry operations where material weight on scaffold platforms is substantially higher than typical construction activities.
Masonry work involves repetitive heavy lifting, prolonged awkward postures, and exposure to respirable crystallite silica dust from cutting concrete masonry units (CMU), brick, and stone. OSHA's silica standard (29 CFR 1926.1153) imposes strict exposure limits and engineering controls that directly impact how masonry cutting operations are performed on federal projects.
This AHA covers CMU block wall construction, brick veneer installation, and associated activities including mortar mixing, scaffold loading, saw cutting, grouting, and reinforcement placement. The initial risk assessment rates uncontrolled masonry hazards at Medium (RAC 3) based on critical severity and occasional probability. With implementation of all controls including limited access zones, bracing, silica controls, and fall protection, residual risk is reduced to Low (RAC 5).
Disclaimer
This content is provided for general informational and educational purposes only. It is not a substitute for a site-specific Job Safety Analysis conducted by a qualified safety professional familiar with your workplace conditions, equipment, and personnel. OSHA citations, BLS statistics, and hazard controls referenced here may not reflect the most current standards or apply to your specific situation. Always consult current OSHA regulations, manufacturer guidelines, and a competent person before beginning work. Health & Safety Systems LLC assumes no liability for actions taken based on this content.
Definable Feature of Work (DFOW)
Masonry Construction
Construction of masonry walls, piers, columns, and veneers using concrete masonry units (CMU), brick, stone, mortar, grout, and reinforcing steel. Includes material staging, mortar mixing, unit laying, saw cutting, grouting, and scaffold operations.
Typical Duration: 2-8 weeks depending on scope and wall area
EM 385-1-1 References
Section 24.D: Masonry Construction
Establishes requirements for masonry construction on USACE projects including limited access zones for unsupported masonry walls, bracing requirements, scaffold load considerations for masonry operations, and protection of workers from wall collapse during construction.
Build This AHA in Minutes
Use JSABuilder to create, manage, and share professional Activity Hazard Analysis worksheets with your team.
Start Free TrialRisk Assessment Code (RAC)
The RAC matrix combines hazard severity and probability to assign a risk level before and after controls are applied. This AHA demonstrates risk reduction from initial to residual conditions.
Initial Risk (Before Controls)
Medium (3)
Severity: Critical | Probability: Occasional
Residual Risk (After Controls)
Low (5)
Severity: Marginal | Probability: Unlikely
Step-by-Step AHA Breakdown
Step 1: Prepare work area and stage masonry materials
Hazards
- Musculoskeletal injuries from manual handling of heavy CMU blocks (30-50 lbs each) and mortar bags (60-80 lbs)
- Struck-by from shifting or collapsing material stacks
- Forklift or telehandler incidents during material placement on scaffold or staging area
Controls
- Use mechanical aids (forklifts, telehandlers, conveyors) to move masonry materials to the work area; limit manual carrying distance
- Stack CMU blocks no more than 6 feet high on firm, level ground; interlock stacks to prevent toppling
- Stage mortar bags on pallets away from foot traffic; do not exceed scaffold platform load capacity when loading materials
- Establish material staging area with clear access for delivery vehicles and forklifts away from the active masonry work zone
Step 2: Set up masonry scaffold and work platforms
Hazards
- Scaffold overload from combined weight of masonry materials, mortar, and workers
- Falls from scaffold during masonry operations
- Scaffold instability from uneven loading or inadequate tie-ins
Controls
- Use heavy-duty scaffold rated for masonry operations (minimum 75 psf platform capacity per 29 CFR 1926.451)
- Install guardrails, mid-rails, and toeboards on all open sides of scaffold platforms
- Tie scaffold to the masonry wall at intervals specified by the scaffold manufacturer and EM 385-1-1 Section 22
- Position scaffold platforms within arm's reach of the work face (typically 4-6 inches from the wall) to prevent overreaching
- Do not stockpile excessive materials on scaffold platforms; maintain material only for immediate use
Step 3: Establish limited access zone for masonry walls under construction
Hazards
- Wall collapse onto workers during construction before grout and reinforcement provide structural integrity
- Unauthorized personnel entering the danger zone adjacent to unbraced masonry walls
Controls
- Establish a limited access zone on the unscaffolded side of all masonry walls under construction per 29 CFR 1926.706(a)
- Limited access zone must extend the height of the wall plus 4 feet, measured perpendicular from the wall face
- Restrict access to the limited access zone to employees actively engaged in constructing the wall
- Mark the limited access zone with barricade tape, stanchions, or fencing with warning signs
- Do not remove the limited access zone until the wall is adequately braced or supported to prevent overturning
Step 4: Mix mortar and grout
Hazards
- Dermatitis and chemical burns from wet cement and mortar (highly alkaline, pH 12-13)
- Inhalation of Portland cement dust during dry mixing
- Entanglement in mortar mixer rotating drum or paddles
Controls
- Wear waterproof gloves, long sleeves, and eye protection when handling wet mortar or grout
- Position mortar mixer upwind and use dust-suppression techniques when adding dry materials
- Never reach into a mortar mixer while it is operating; turn off and lock out before clearing jams
- Mix mortar and grout per project specifications and ACI/TMS standards; do not add excessive water to improve workability
- Provide eyewash station within 25 feet of mortar mixing area for cement splash exposure
Step 5: Cut masonry units with masonry saw
Hazards
- Respirable crystalline silica exposure from dry cutting CMU, brick, or stone
- Lacerations from masonry saw blade
- Noise exposure exceeding 100 dBA during cutting operations
- Eye injuries from flying chips and debris
Controls
- Use wet cutting methods on masonry saws to suppress silica dust; maintain continuous water flow to the blade per OSHA Table 1 (29 CFR 1926.1153)
- If wet cutting is not feasible, use a saw equipped with a HEPA-filtered dust collection system and operate outdoors or in a ventilated area
- Implement a written silica exposure control plan per 29 CFR 1926.1153(g)
- Wear a minimum N95 respirator when cutting masonry; upgrade to half-face APR with P100 cartridges for extended cutting operations or when engineering controls are insufficient
- Wear safety glasses with side shields, hearing protection (NRR 25+ plugs or muffs), and cut-resistant gloves during all cutting operations
- Secure masonry units in the saw clamp before cutting; never freehand cut masonry units
Step 6: Lay masonry units and build wall sections
Hazards
- Ergonomic injuries from repetitive bending, lifting, and twisting (masons lift an estimated 200+ blocks per day)
- Struck-by from falling masonry units or tools from upper scaffold levels
- Dermatitis from prolonged skin contact with wet mortar
Controls
- Rotate masons between tasks to reduce repetitive strain; provide rest breaks in accordance with the ergonomic risk assessment
- Adjust scaffold platform height frequently to keep the work zone between knuckle and shoulder height
- Use mechanical block-laying aids where practical for blocks exceeding 35 pounds
- Install toeboards and debris netting on scaffolds to prevent mortar and blocks from falling on workers below
- Wear waterproof gloves when handling mortar; apply barrier cream to exposed skin at the start of each shift
Step 7: Install reinforcement and pour grout
Hazards
- Wall blowout from excessive grout lift height or pour rate
- Impalement on exposed vertical reinforcing steel
- Burns from grout splash during pumping operations
Controls
- Limit grout pour lifts to 4 feet for fine grout and 8 inches for coarse grout unless higher lifts are approved by the engineer of record and demonstrated by prism testing
- Cap all exposed vertical rebar with OSHA-compliant rebar caps (mushroom-type or trough-type rated for the impalement hazard)
- Consolidate grout by mechanical vibration or puddling per ACI 530.1/TMS 602 specifications
- Wear face shield and waterproof gloves during grout pumping operations
- Inspect cleanout openings at the base of grout lifts to verify cell cavities are free of mortar droppings and debris before grouting
Step 8: Install wall bracing and remove limited access zone
Hazards
- Wall overturning from wind loads before permanent structural connections are made
- Premature removal of bracing before wall has adequate strength
Controls
- Install wall bracing per the structural engineer's bracing plan; brace at intervals not exceeding the design spacing
- Bracing must resist a minimum wind load of 5 psf applied perpendicular to the wall face (or the design wind speed, whichever is greater)
- Do not remove bracing or limited access zone until the masonry wall has achieved design strength and permanent lateral support (floor diaphragm, roof, or cross walls) is in place
- Document bracing installation and removal in the daily quality control report
Competent & Qualified Persons
EM 385-1-1 requires designated competent and qualified persons for specific activities. These individuals must have the training, experience, and authority to identify hazards and take corrective action.
Masonry Competent Person
Must be able to identify existing and predictable masonry construction hazards including wall stability, scaffold loading, limited access zone requirements, and bracing adequacy. Must have authority to take immediate corrective measures including stopping work when hazardous conditions are identified.
EM 385-1-1 Reference: Section EM 385-1-1 Section 24.D
Site Safety and Health Officer (SSHO)
Must hold a 30-hour OSHA Construction safety course and have a minimum of 5 years construction safety experience. Responsible for reviewing this AHA, verifying controls are implemented, conducting daily safety inspections, and maintaining the silica exposure control plan.
EM 385-1-1 Reference: Section EM 385-1-1 Section 01.A.13
Scaffold Competent Person
Must be designated specifically for masonry scaffolding which carries substantially higher platform loads than standard construction scaffolds. Must verify scaffold capacity meets heavy-duty rating (75 psf minimum) and inspect daily.
EM 385-1-1 Reference: Section EM 385-1-1 Section 22.A.01
Silica Competent Person
Must be designated to implement and monitor the written silica exposure control plan per 29 CFR 1926.1153(g). Must be able to verify that engineering controls (wet cutting, dust collection) are functioning properly and that respiratory protection is adequate.
EM 385-1-1 Reference: Section EM 385-1-1 Section 06.H
Equipment, Training & Inspection Requirements
Required Equipment
Training Requirements
- OSHA 10-Hour Construction Safety (minimum for all masonry workers)
- OSHA 30-Hour Construction Safety (required for SSHO and superintendents)
- Silica awareness training per 29 CFR 1926.1153(i) covering health effects, exposure limits, and engineering controls
- Respiratory protection training and fit testing per 29 CFR 1910.134 for all workers who may be exposed to silica during cutting operations
- Scaffold user training per 29 CFR 1926.454 with emphasis on heavy-duty scaffold load limits for masonry operations
- Fall protection training including harness use, guardrail systems, and scaffold fall protection
- Hazard communication training for mortar, cement, grout, and masonry sealants
- Ergonomic awareness training covering proper lifting techniques, work rotation, and early symptom reporting
- Site-specific hazard orientation covering this AHA, the limited access zone plan, and the silica exposure control plan
- EM 385-1-1 awareness training specific to Section 24.D masonry requirements
Inspection Requirements
- Daily inspection of masonry scaffold by competent person before each shift, with emphasis on platform load and tie-in integrity
- Daily inspection of limited access zone barricades and signage before masonry work begins
- Inspection of wall bracing at the start of each shift and after high wind events
- Daily inspection of masonry saw water supply and dust suppression system before cutting operations
- Weekly silica exposure monitoring or verification that Table 1 controls are properly implemented
- Inspection of all mortar and grout materials for proper storage, mix proportions, and shelf life
- Inspection of rebar caps on all exposed vertical reinforcement at the start of each shift
- Weekly documented safety inspection by the SSHO covering all masonry operations
- Post-event inspection of masonry walls after wind events exceeding 25 mph or seismic activity
Applicable OSHA Standards
29 CFR 1926.706
Requirements for Masonry Construction
Establishes limited access zone requirements for masonry walls under construction, bracing requirements to prevent wall collapse, and restricted access provisions to protect workers from unsupported masonry wall hazards.
29 CFR 1926.1153
Respirable Crystalline Silica
Sets permissible exposure limit of 50 micrograms per cubic meter as an 8-hour TWA for respirable crystalline silica. Table 1 specifies required engineering controls for masonry cutting including wet methods and dust collection systems.
29 CFR 1926.451
General Requirements for Scaffolds
Establishes scaffold capacity requirements. Masonry scaffolds must be rated heavy-duty (75 psf) to accommodate the combined weight of masonry materials, mortar, and workers on the platform.
29 CFR 1926.502
Fall Protection Systems Criteria and Practices
Specifies guardrail height, strength, and toeboard requirements for fall protection on scaffold platforms and at wall openings during masonry construction.
29 CFR 1910.134
Respiratory Protection
Requires a written respiratory protection program, medical evaluations, fit testing, and training for workers wearing respirators during masonry cutting operations when engineering controls are insufficient.
Required Personal Protective Equipment
Frequently Asked Questions
What is a limited access zone for masonry construction?
A limited access zone (LAZ) is a controlled area on the non-scaffold side of a masonry wall under construction where access is restricted to prevent worker injury from wall collapse. Per 29 CFR 1926.706(a), the LAZ must extend the height of the wall plus 4 feet from the base of the wall and run the entire length of the wall. Only employees actively engaged in constructing the wall are permitted in the LAZ. The zone must remain in place until the wall is permanently braced or has achieved adequate strength to be self-supporting.
How does the AHA address silica exposure during masonry cutting?
The AHA requires compliance with OSHA Table 1 controls from 29 CFR 1926.1153 for all masonry cutting operations. The primary control is wet cutting with continuous water supply to the saw blade, which reduces silica dust generation by approximately 80-90%. When wet cutting is not feasible, a masonry saw equipped with a HEPA-filtered dust collection system must be used. A written silica exposure control plan must be maintained on-site, and a designated silica competent person must verify that controls are functioning properly.
Why does masonry require heavy-duty scaffold ratings?
Masonry scaffolds carry substantially more weight than scaffolds used for other trades because masonry materials are dense and heavy. A single pallet of CMU blocks weighs approximately 2,800 pounds, and mortar adds additional dead load. OSHA requires masonry scaffolds to be rated heavy-duty at a minimum of 75 pounds per square foot of platform area. The scaffold must also maintain a 4:1 safety factor, meaning it must support four times the maximum intended load. The scaffold competent person must verify that combined material, worker, and equipment weight does not exceed the rated capacity.
When must masonry wall bracing be installed?
Masonry wall bracing must be installed as the wall is constructed, at intervals specified by the structural engineer's bracing plan. Bracing must resist lateral forces (primarily wind) that could overturn the wall before permanent structural connections (floor diaphragms, cross walls, or roof framing) are in place. Bracing typically consists of adjustable diagonal braces anchored to concrete deadmen or existing structure. Bracing must not be removed until the wall has achieved design strength and permanent lateral support is connected.
What ergonomic controls should be included in a masonry AHA?
Masonry is one of the most physically demanding construction trades. A mason may lift 200 or more blocks per day, each weighing 30-50 pounds, in addition to handling mortar. Ergonomic controls include adjusting scaffold height frequently to keep the work zone between knuckle and shoulder height, rotating workers between laying, cutting, and material handling tasks, using mechanical aids for transporting materials, scheduling regular rest breaks, and using lighter-weight CMU units where the structural design permits. Workers should be trained to recognize early symptoms of musculoskeletal disorders and report them promptly.