Maintenance of Unit Masonry AHA (Activity Hazard Analysis / Job Hazard Analysis)
Updated 2026-06-23
A Maintenance of Unit Masonry AHA (Activity Hazard Analysis / Job Hazard Analysis) is the plan that keeps the crew maintaining unit masonry safe from the tuckpointing and mortar-removal silica dust, through the access and work at height, and around the material handling and masonry stability. Maintenance of unit masonry repairs and maintains brick, block, and unit masonry — combining the tuckpointing and mortar-removal-silica-dust hazard, the access and work-at-height hazard, and the material-handling and masonry-stability hazard. This guide walks through building a Maintenance of Unit Masonry AHA that names the tuckpointing/mortar-removal-silica-dust, access/ work-at-height, and material-handling/masonry-stability hazards and assigns the silica, access, and stability controls that hold up in the field.
Why maintenance of unit masonry needs its own AHA
Maintenance of unit masonry is the repair and maintenance of unit masonry — brick, concrete block (CMU), clay tile, and similar masonry units — including repointing/tuckpointing (removing and replacing deteriorated mortar joints), replacing damaged units, cleaning, and repairing masonry walls and assemblies. This heads the masonry work (Division 04), transitioning from the concrete division. The defining feature is the masonry repair work, most notably tuckpointing: grinding and cutting out old mortar joints generates silica dust (both the mortar and the masonry units contain silica), the work is on walls (access and work at height), and it involves handling masonry materials around existing (sometimes deteriorated) masonry. The hazards combine the tuckpointing and mortar-removal-silica-dust (removing/grinding out old mortar joints (tuckpointing) and cutting masonry — the silica hazard (grinding out mortar joints and cutting masonry generates respirable silica — mortar and masonry contain silica)), the access and work-at-height (masonry maintenance is on walls/facades — the access and fall hazards (scaffolds, lifts, ladders to reach the masonry, often at height on building facades)), the material- handling and masonry-stability (handling masonry units/materials and the stability of the existing (possibly deteriorated) masonry — the handling and stability/collapse hazards), and the mortar-contact/weather. The tuckpointing/mortar-removal-silica-dust and the access/work-at-height justify a dedicated AHA.
Breaking maintenance of unit masonry into steps
The steps for a Maintenance of Unit Masonry AHA follow the maintenance:
- Assess the masonry condition and stability
- Set up access (scaffold/lift) with fall protection
- Set up silica control for mortar removal/cutting
- Remove deteriorated mortar/units (silica control)
- Repoint/replace mortar and units (mortar contact)
- Manage the silica, access, and stability hazards
- Clean the masonry as required
- Complete
Each step carries a hazard, and the tuckpointing/mortar-removal-silica-dust, the access/work-at-height, and the material-handling/masonry-stability are where the most significant risks concentrate.
The hazards step by step
Tuckpointing and mortar-removal-silica-dust
Removing/grinding out old mortar joints (tuckpointing) and cutting masonry — the silica hazard (grinding out mortar joints and cutting masonry generates respirable silica — mortar and masonry contain silica). The controls are silica control for tuckpointing/mortar removal (grinding out mortar joints with a grinder or tuckpointing tool generates respirable silica — on-tool dust extraction, respiratory protection, per the silica standard's tuck- pointing/grinding provisions; tuckpointing is a specifically-addressed high-silica task), and the silica controls. The tuckpointing/mortar-removal-silica-dust is the primary defining hazard — grinding out mortar joints generates respirable silica. (These follow the silica fundamentals.)
Access and work-at-height
Masonry maintenance is on walls/facades — the access and fall hazards (scaffolds, lifts, ladders to reach the masonry, often at height on building facades). The controls are safe access to the masonry (properly erected scaffolds, aerial lifts, or ladders to reach the masonry — much masonry maintenance is at height on building facades), fall protection for the at-height work, and the access/height controls. The access/work-at-height is a defining hazard — masonry maintenance is often at height on facades. (These follow the fall-protection and scaffold fundamentals.)
Material-handling and masonry-stability
Handling masonry units/materials and the stability of the existing (possibly deteriorated) masonry — the handling and stability/collapse hazards. The controls are safe material handling (masonry units, mortar, materials — manual handling, hoisting to height), assessing the existing masonry stability (deteriorated masonry may be unstable — assessing before working on/near it, shoring/bracing where a wall is unstable, not undermining the masonry), and the handling/stability controls. The material-handling/masonry-stability is a defining hazard — existing masonry may be unstable and materials must be handled. (These follow the material-handling and masonry-stability fundamentals.)
Mortar-contact/weather
The mortar contact and weather (caustic mortar, exterior weather exposure) carries the contact/weather hazard. The controls are mortar contact protection (mortar is cement-based/caustic), weather/exposure management, and the contact/weather controls. (These follow the cement-contact fundamentals.)
A simple Maintenance of Unit Masonry AHA structure
| Step | Hazard | Control | Standard |
|---|---|---|---|
| Assess | Instability | Assess the masonry condition and stability | project |
| Access | Fall | Set up access (scaffold/lift) with fall protection | OSHA 1926.451 |
| Silica control | Silica | Set up silica control for mortar removal/cutting | OSHA 1926.1153 |
| Remove mortar | Silica | Remove deteriorated mortar/units (silica control) | OSHA 1926.1153 |
| Repoint | Mortar contact | Repoint/replace mortar and units (mortar contact) | project |
| Clean | Contact | Clean the masonry as required | project |
Tuckpointing-silica control and access/stability safety
A Maintenance of Unit Masonry AHA centers on tuckpointing-silica control and access/stability safety. The tuckpointing-silica control addresses the respirable silica from mortar removal — controlled by silica control for tuckpointing/mortar removal (on-tool dust extraction, respiratory protection, per the silica standard's tuckpointing provisions). The access/stability safety addresses the at-height work and the existing masonry — controlled by safe access with fall protection (scaffolds, lifts, ladders on facades) and assessing the existing masonry stability (deteriorated masonry may be unstable). And the material handling and mortar contact get handling and contact controls. An AHA built on tuckpointing-silica control and access/stability safety, with handling controls, addresses the hazards that define maintenance of unit masonry.
From the field: what actually goes wrong
In fourteen years across federal, heavy civil, and industrial projects, maintenance of unit masonry repairs and maintains brick, block, and unit masonry, and it heads the masonry work as the concrete division gives way to Division 04. Its defining hazards carry the silica theme from the concrete-cutting cluster right into masonry, because masonry maintenance — specifically tuckpointing — is itself a recognized high-silica task. The tuckpointing and mortar-removal-silica-dust hazard is a primary defining concern — repointing (tuckpointing) requires grinding and cutting out the old, deteriorated mortar from the joints before repointing them, and grinding out mortar joints (typically with an angle grinder or tuckpointing grinder) generates respirable crystalline silica, because both the old mortar and the masonry units contain silica; tuckpointing is specifically called out in the OSHA silica standard as a task requiring dust control. So silica control (on-tool dust extraction on the grinder capturing the dust, plus respiratory protection, per the silica standard's tuckpointing and grinding provisions) is the central control. Tuckpointing is a high-silica task just like concrete grinding, and it carries the same dust-control requirement.
The access/work-at-height and the material-handling/masonry-stability are the other defining hazards. On the projects I have run, masonry maintenance is done on walls and facades, which are often at height (multi-story building facades), so safe access (properly erected scaffolds, aerial lifts, or ladders to reach the masonry) and fall protection for the at-height work are the controls — falls from facade access are a major masonry-work hazard. And the material-handling/masonry-stability hazard is handling the masonry units, mortar, and materials (manual handling and hoisting to height) and, importantly, the stability of the existing masonry: masonry being maintained is often deteriorated (which is why it needs maintenance), and deteriorated masonry may be unstable, so assessing the existing masonry's stability before working on or near it (and shoring or bracing an unstable wall, and not undermining the masonry during the work) is a control. Working on deteriorated masonry that could collapse is a real hazard. The caustic mortar contact and the exterior weather exposure round it out. This heads the masonry division. The AHA built on tuckpointing-silica control and access/stability safety is the one that protects the masonry-maintenance crew.
The bottom line
A Maintenance of Unit Masonry AHA names the tuckpointing/mortar-removal-silica-dust, the access/work-at-height, and the material-handling/masonry-stability hazards with specific controls — silica control for tuckpointing (grinding out mortar joints is a recognized high-silica task), safe access with fall protection for the at-height facade work, and assessing the stability of the existing (possibly deteriorated) masonry. The tuckpointing-silica control and the access/stability safety are the defining concerns. The AHA that manages both is the one that protects the crew.
Frequently asked questions
Why is tuckpointing a silica hazard?
Repointing (tuckpointing) requires grinding and cutting out the old, deteriorated mortar from the joints before repointing, and grinding out mortar joints (typically with an angle grinder or tuckpointing grinder) generates respirable crystalline silica, because both the old mortar and the masonry units contain silica — tuckpointing being specifically called out in the OSHA silica standard as requiring dust control. Controls are silica control for tuckpointing/mortar removal (on-tool dust extraction, respiratory protection, per the silica standard's tuckpointing/grinding provisions), and the silica controls.
What access and fall hazards apply?
Masonry maintenance is done on walls and facades, often at height on multi-story building facades. Controls are safe access to the masonry (properly erected scaffolds, aerial lifts, or ladders), fall protection for the at-height work, and the access/height controls — falls from facade access being a major masonry-work hazard.
Why is masonry stability a concern?
Masonry being maintained is often deteriorated (which is why it needs maintenance), and deteriorated masonry may be unstable. Controls are safe material handling (masonry units, mortar, materials — manual handling, hoisting to height), assessing the existing masonry stability (assessing before working on/near it, shoring/bracing where a wall is unstable, not undermining the masonry), and the handling/stability controls.
What is maintenance of unit masonry?
Maintenance of unit masonry is the repair and maintenance of unit masonry — brick, concrete block (CMU), clay tile, and similar units — including repointing/tuckpointing, replacing damaged units, cleaning, and repairing masonry walls. Because tuckpointing generates respirable silica, the work is at height on facades, and the existing masonry may be unstable, those hazards apply.
Related AHAs and JHAs
- Maintenance of Stone Assemblies AHA — the related stone maintenance
- Common Work Results for Masonry AHA — the masonry work fundamentals
- Masonry and Block Wall Construction JHA — the masonry-construction fundamentals
- Concrete Surface Grinding JHA — related grinding/silica work
Written by Mustafa Tok, CSP, ASP, CHST — OSHA Authorized Outreach Trainer with 14+ years of international construction safety experience across federal, heavy civil, and industrial projects.