Roof Curb Installation JHA (Job Hazard Analysis / Activity Hazard Analysis)
Updated 2026-06-23
A Roof Curb Installation JHA (Job Hazard Analysis / Activity Hazard Analysis) is the plan that keeps the crew installing roof curbs from falling through the roof opening the curb frames, being cut by the sharp metal, or strained handling the curbs. Roof curb installation sets the raised frames that support and seal rooftop equipment (HVAC units, fans, skylights) at their roof penetrations — combining the fall-through hazard of the opening the curb surrounds, the sharp-metal cut hazards, and the curb-handling hazards. This guide walks through building a Roof Curb Installation JHA that names the fall-through-opening, cut, and handling hazards and assigns the opening-protection, cut, and handling controls that hold up in the field.
Why roof curb installation needs its own JHA
Roof curb installation sets the roof curbs — the raised frames (metal or wood) that surround a roof opening and support and seal rooftop equipment such as HVAC/rooftop units, exhaust fans, skylights, and other equipment at their penetrations through the roof — including framing the opening, setting the curb, and flashing it in. The defining hazard is the roof opening the curb surrounds. The hazards combine the fall-through opening (the curb surrounds a roof opening — the opening for the equipment/duct/fan is a fall-through hazard until it is covered, protected, or the equipment is set, and the curb work happens at and around this opening), the sharp metal (the metal curbs and any cut roof/deck metal — cut hazards), the handling (the curbs are handled and set — handling and hoisting hazards, and larger curbs are heavy), and the cutting and any hot work. The fall-through opening and the sharp metal justify a dedicated JHA.
Breaking roof curb installation into steps
The steps for a Roof Curb Installation JHA follow the curb:
- Establish fall protection and plan the opening
- Frame or prepare the roof opening
- Protect the open roof opening
- Handle and set the curb over the opening
- Fasten and flash the curb
- Manage the fall-through, cut, and handling hazards
- Protect the opening until equipment is set
- Verify the installation
Each step carries a hazard, and the fall-through opening, the sharp metal, and the handling are where the most serious risks concentrate.
The hazards step by step
Fall-through opening
The curb surrounds a roof opening — the opening for the equipment, duct, or fan is a fall-through hazard until it is covered, protected, or the equipment is set, and the curb work happens at and around this opening, so the crew works adjacent to a fall-through opening. The controls are protecting the open roof opening (covering or guarding the opening, keeping it protected until the equipment is set or the opening otherwise closed), guardrails around the opening, not leaving the opening unprotected, and the roof-opening-protection controls. The fall-through the opening the curb surrounds is the defining hazard, and it persists after the curb is set until the equipment is installed (the curb frames an open hole). (These follow the roof-opening- protection and roof-hatch fundamentals.)
Sharp metal
The metal curbs and any cut roof/deck metal have sharp edges — cut and laceration hazards from handling the curbs and the cut roof/deck edges. The controls are cut-resistant gloves and PPE, careful handling, managing the sharp cut edges, and awareness of the sharp edges. (These follow the metal-panel fundamentals.)
Handling
The curbs are handled and set, and larger curbs (for big rooftop units) are heavy — handling and hoisting hazards. The controls are safe handling and hoisting of the curbs, team handling, and the material-handling controls. (These follow the material-handling fundamentals.)
Cutting and hot work
Cutting or framing the opening and any welding of metal curbs carry cutting and hot-work hazards (and cutting metal deck drops sparks/debris below). The controls are safe cutting, the hot-work controls where welding/ cutting metal (fire watch, protecting below), and managing the below-deck hazard. (These follow the hot-work fundamentals.)
A simple Roof Curb Installation JHA structure
| Step | Hazard | Control | Standard |
|---|---|---|---|
| Plan/establish protection | Fall | Fall protection, plan the opening and its protection | OSHA 1926.501 |
| Frame opening | Fall-through / cut / hot work | Cut controls, hot-work controls, protect below | OSHA 1926.352 |
| Protect opening | Fall-through | Cover/guard opening, guardrails, keep protected | OSHA 1926.501(b)(4) |
| Handle/set curb | Strain / struck-by | Safe handling and hoisting, team handling | OSHA 1926.250 |
| Fasten/flash curb | Cut / fall | Cut protection, fall protection at opening | OSHA 1926.501 |
| Protect until equipment set | Fall-through | Keep opening protected until equipment installed | OSHA 1926.502 |
Opening protection and cut protection
A Roof Curb Installation JHA centers on opening protection and cut protection. The opening protection addresses the defining hazard — the curb surrounds a roof opening that is a fall-through hazard until the equipment is set or the opening closed, and the curb frames an open hole that persists after the curb is set — controlled by protecting the open roof opening (covering or guarding it, keeping it protected until the equipment is set), guardrails around the opening, and not leaving it unprotected. The cut protection addresses the sharp metal curbs and cut roof/deck metal — controlled by cut-resistant gloves and careful handling. A JHA built on opening protection and cut protection, with handling and hot-work controls, addresses the hazards that define roof curb installation.
From the field: what actually goes wrong
In fourteen years across federal, heavy civil, and industrial projects, roof curb installation carries a fall-through hazard that persists longer than people expect: the curb surrounds a roof opening — for a rooftop HVAC unit, a fan, ductwork, or a skylight — and that opening is a fall-through hazard until the equipment is set or the opening is otherwise closed. The subtle point is that setting the curb does not close the opening — the curb frames an open hole, so the fall-through hazard persists after the curb is installed, right up until the equipment is set on the curb. The crew works at and around this opening throughout. The controls are protecting the open roof opening — covering or guarding it, and keeping it protected until the equipment is set — guardrails around the opening, and never leaving the opening unprotected, applying the roof-opening- protection discipline to the opening the curb surrounds.
The sharp metal and the handling are the other defining hazards. The metal curbs and the cut roof/deck metal have sharp edges — a cut hazard controlled by cut-resistant gloves and careful handling. And the curbs are handled and set, with larger curbs for big rooftop units being heavy, bringing handling and hoisting hazards. On the projects I have run, cutting or framing the opening and any welding of metal curbs bring cutting and hot-work hazards, and cutting metal deck drops sparks and debris below. The JHA built on opening protection and cut protection is the one that protects the curb crew and anyone below.
The bottom line
A Roof Curb Installation JHA names the fall-through-opening, the cut, and the handling hazards with specific controls — protecting the open roof opening the curb surrounds (covering/guarding it, keeping it protected until the equipment is set, since the curb frames an open hole) for the fall-through hazard, cut-resistant gloves for the sharp metal, and safe handling/hoisting for the curbs. The fall-through the opening is the defining hazard, persisting until the equipment is set. The JHA that manages it, with the cut and handling controls, is the one that protects the crew.
Frequently asked questions
Why does the fall-through hazard persist after the curb is set?
Setting the curb does not close the opening — the curb frames an open hole (for the equipment, duct, or fan), so the fall-through hazard persists after the curb is installed, right up until the equipment is set on the curb or the opening is otherwise closed. Controls are protecting the open roof opening (covering or guarding it), keeping it protected until the equipment is set, guardrails around the opening, and not leaving it unprotected.
What is a roof curb for?
A roof curb is the raised frame (metal or wood) that surrounds a roof opening and supports and seals rooftop equipment — HVAC/rooftop units, exhaust fans, skylights, and other equipment — at their penetrations through the roof, providing a level, weatherproofed base. The curb surrounds an opening, which is why the fall-through-opening hazard is central to installing it.
What cut hazards does curb installation pose?
The metal curbs and any cut roof/deck metal have sharp edges — cut and laceration hazards from handling the curbs and the cut roof/deck edges. Controls are cut-resistant gloves and PPE, careful handling, managing the sharp cut edges, and awareness of the sharp edges.
What handling hazards do curbs pose?
The curbs are handled and set, and larger curbs (for big rooftop units) are heavy — handling and hoisting hazards getting them to the roof and positioned over the opening. Controls are safe handling and hoisting of the curbs, team handling, and the material-handling controls, coordinated with the opening protection.
Related JHAs
- Roof Hatch Installation JHA — the related roof-penetration opening work
- Roof Opening Protection JHA — the opening-protection fundamentals
- Roof Work JHA — the general roof-work fundamentals
- Roof Flashing Installation JHA — the flashing at the curb
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.