Most state civil judiciary legally consider roofing within the “inherently dangerous” occupation category. When you consider the steep pitches, heights to grade, surface traction conditions, material handling tasks, bulk material weights, environmental factors of wind and weather and the perpetual force gravity on the worker’s center of mass, it is no wonder that falls from or through roofs cause numerous injuries and deaths every year.

Photos courtesy of Capital Safety.

Most state civil judiciary legally consider roofing within the “inherently dangerous” occupation category. When you consider the steep pitches, heights to grade, surface traction conditions, material handling tasks, bulk material weights, environmental factors of wind and weather and the perpetual force gravity on the worker’s center of mass, it is no wonder that falls from or through roofs cause numerous injuries and deaths every year. Therefore, I believe that the complete or selective demolition of any roof should be seriously considered an “extraordinarily dangerous” task, a term I define as:

“Any work procedure practiced in the performance of an inherently dangerous occupation, which routinely or prospectively exposes one or more workers to either potential or existing Immediately Dangerous to Life and Health (IDLH) hazards with significantly high probability and severity risk ratings.”

Whenever I think about a blaster’s job, I’m usually grateful I’m in another line of work. One explosives specialist told me in his occupation only the experts get to retire. While we may all agree that hard-rock blasting is considered an “inherently dangerous” occupation, dealing safely with a misfired shot may be reasonably considered an “extraordinarily dangerous” task, even for a competent blaster. When something which was initially dangerous has gone seriously wrong, it is up to the best-of-the-best, master blaster to figure it out and safety abate the invisible hazard. That certainly qualifies as extraordinarily dangerous.

The same holds true when a demolition job requires you to partially or totally disassemble a structurally unsound building. Employee training and a sound demolition plan are the best defenses against injury, illness and death. Before planning, and even training, can be effective, we must first inspect and analyze the structure for potential physical hazards. Not the least of these hazards is the condition of structural items upon which we may have to walk or work. They may have been damaged, deteriorated or otherwise compromised by adjoining defects. When it comes to re-roofing an existing deck, this would entail a reasonable inspection activity. OSHA does not necessarily consider the solitary act of removing and replacing the waterproofing materials of a roof to fall under their Demolition Standard (Subpart T). However, it is often left up to the inspecting compliance officer to determine the extent of the employer’s obligation when he or his employees detect damaged roof structures during their re-roofing operation.

I know of many roofing companies and general contractors who provide roof re-framing/re-sheathing services to their clients as an extra add-item to their contracted roofing services whenever they detect damaged structures. Once the contractor removes damaged materials below the underlayment, he has begun to venture into selective demolition, which then regulates his demolition work under Subpart T of the OSHA Construction Standard. Depending on site-specific conditions, this type of work may be considered by some as an “extraordinarily dangerous” task. I am one of those people.

Every jobsite analysis should contain a safety program which specifies appropriate personal fall arrest system. (Photo courtesy of Evans Roofing Company.)

Risk Assessment

It is the nature of structural demolition to directly or indirectly remove either superstructural or infrastructural elements which may directly affect the stability or integrity of the demolition worker’s potential walking/working surfaces. Add to this any factors which initially make roofing “inherently dangerous” and you’ve ostensibly created an occupational condition with a relatively high Risk Assessment Value (RAV). A RAV compares four categories of accident probability (A-High, B-Moderate, C-Low, D-Effectively Null) on the horizontal axis with four categories of accident severity (1-High, 2, Moderate, 3-Low, 4-Effectively Null) on the vertical axis in a X-Y graphic matrix. The system was developed by the U.S. Navy under the auspices of NAVOSH. Any safe work practice which repeatedly works successfully, under battle stress, in war zone conditions, is sufficiently time-tested to work on a construction site.

It is important to determine the extent of deck and rafter decay. (Photo courtesy of Evans Roofing Company.)

In my 40 years of construction experience, the majority of roof demolition tasks may have RAVs ranging from A1 to B3, depending on a wide range of factors affecting site conditions and workers’ activities. The RAV for trained and experienced roofers stripping asphalt shingles off of a 4:12 pitch deck while implementing PFAS with slide guards at all of the eaves may be considered a (B2) task, while accessing a structurally damaged 12:12 tile roof after a hurricane with obvious framing instability and foundation degradation could be considered A1. Occupations such as firefighting and roofing have employees who often access a roof with an unknown degree of structural integrity, due to conditions such as fire or prolonged water and ice damage. Their employers should logically assume their Risk Assessment Value to be a critical (A1) for their tasks, until they can prove otherwise with a comprehensive structural inspection. While this is not always easily accomplished, even the incident commander on the scene of a fire will perform a complete walk-around site survey with his safety officer as close as feasible before he asks his teams to assault a questionable roof structure. The same can be said for a roofing contractor who is responsible for his crew on a roof with questionable degree of strength or stability. 

OSHA requires the roofing employer to investigate the substructure prior to permitting employees to begin demolition operations. (Photo courtesy of Evans Roofing Company.)

Employer Commitment

Not only should every “extraordinarily dangerous” task be risk evaluated by the roofing contractor and his competent person (CP) but a site-specific, task-specific, worker-specific Job Safety Analysis (JSA) should be completed before any work begins that could expose your roofers to injury. I have participated in a number of roofing accident cases where the contractor’s omission of this basic process of hazard awareness prior to his employees performing an “extraordinarily dangerous” task was reasonably considered an exhibition of willful (or even malicious) neglect. When the evidence and deposition testimonies indicate the employer’s disregard for roof hazard awareness, the judge has made a summary judgment for a settlement in the case before a trial, stipulating the employer’s “callous disregard” for his employees’ safety on the job.

While the penalty criteria for summary judgment may vary from state to state, the principle remains the same. The general duty to provide a safe and healthy workplace and practices remains always within the purview of the direct and controlling employers. Therefore, selective or total roof demolition tasks should be assigned only to your best-trained and evaluated employees, expert climbers, competent in fall protection strategies, skilled in material handling and rigging, equipped with and trained in the use of the best personal protective equipment (PPE) available. Select a competent lead roofer or foreman who has shown a genuine ability to follow plans, make intelligent decisions and implementing changes only when it is appropriate. Make sure you’ve completely trained and clearly designated your demolition foreman as a competent person in your demolition plan. Remember, with the discharge of all of your responsibility onto his shoulders comes all of your authority to take prompt corrective actions whenever necessary. “Safety first” is never followed by the words “when it’s convenient and affordable.”

A site-specific, task-specific, worker-specific job safety analysis should be completed before any work begins that could expose workers to injury. (Photo courtesy of Evans Roofing Company.)

The pre-demolition Job Safety Analysis (JSA) is the prime directive necessary to assemble a written Roof Demolition Safety Plan (RDSP). An integral part of the JSA is the initial engineering survey. Every roof framer and waterproofer knows you cannot stray from the critical path of assembly during roof construction. The second floor top plates should be equilateral, squared, plumbed and braced to prevent movement before any roof framing begins. Rafters and collar ties must be installed plumb on layout and adequately braced to prevent collapse or distortion before sheathing can be applied uniformly. Sheathing must be laid tight and flashing and skip courses must lap and fold properly to prevent shingles, slates and shakes from leaking. Likewise, in reverse, the deconstruction of a roof will require the competent person for demolition to develop the RDSP before demolition work can begin. While the reasons for planning demolition might not have anything to do with the quality of the finished product, it will certainly pertain to the lives and safety of the demolition workers. The JSA is an extremely important, written guideline procedure for creating an RDSP. Like the JSA, the engineering survey is also compiled, signed and dated by the employer’s designated competent person.

The most common reasons some roofs are to be removed include physical damage or decay, which can affect their structural capacity to quantitatively resist the forces created during the process of demolition. Unfortunately, the forces often required to take a building down carefully are often sufficient to cause it to fall down accidentally. There could be several areas to examine depending on they type of damage to the structure. If there was impact damage, how much did it affect the rafters? How extensive is the deck and/or rafter decay? How far did the fire travel behind the walls and ceilings? How much will the next stage of demolition weaken the already damaged materials? If the evaluation is undermanned or rushed before the demolition process begins, the result is an entirely unknown hazardous exposure. Take the time to conduct a proper site inspection. The JSA and engineering survey are offensive safety practices meant to ensure nothing falls between the cracks when it comes to the employees’ safety on the roof during demolition.

Engineering Survey

No one lives forever and neither do our buildings. Every day a building stands, it is in the process of decay and eventual collapse. The envelope of every building is continually being bombarded by the exterior elements. Excessive condensation caused by poor or nonexistent sub-deck ventilation can also attack a roof from within. Under the right conditions of moisture and temperature, decay and white mold growth can seriously weaken a roof’s cellulose frame and deck within a half-dozen seasonal cycles. Every roof demolition project, large or small, should begin with a thorough structural inspection. Rule No. 1 through Rule No. 10: Assume nothing. After all, it’s estimated less than a quarter of existing roof jobs are due to a redesign or renovation rather than surface deterioration or structural degradation. As a portion of the building’s envelope continually exposed to harsh environments, UV radiation, physical strike damage, intense structural wind, rain, snow and ice loading, and widely ranging temperature extremes, we may expect a certain amount of deterioration from any roof system, whether or not it may be observable from above.

Many low-slope or flat industrial and commercial roofs exhibit large areas of ponding and significant “snow-holes” here in the Northeast. These are areas where prolonged snow and water/ice loads are physically captured or dammed between roof features, such as penthouses, water tanks, elevator hoist houses, dormers, cooling towers and even structural deflection of materials. These conditions may often lead to “buried” or “blind” water infiltration, rotting wood fibers or oxidizing ferrous members. As ancillary features are added over the years (such as UHF and repeater towers, and roof gardens), their live-load applications to deck and substructure might change significantly. The original structural design may not have been designed to adequately resist the current loads or their transference vectors. Members move in unbraced directions, diaphragms (sheathing) compress, torque and lift in unexpected ways. Shear fasteners are often extracted by migratory, tensional forces. A well-engineered roof structure is designed with over 200 percent safety factor to account for the GUFF (great unknown fudge factor).

The jobsite safety analysis and engineering survey are offensive safety practices meant to ensure employees’ safety on the roof during demolition. (Photo courtesy of Evans Roofing Company.)

Sometimes the actual failure zone of a roof’s deck and substructure is only a dozen square feet in area. This is ample to send an unaware employee into a 4-foot free fall with more than enough impact force to dislocate a shoulder, break a clavicle, or worse - all this damage in less time than you can blink. The residual impact forces on rotten materials could send him plummeting down to the floor 8 feet or 10 feet below with potentially lethal terminal effect.

OSHA’s Demolition Standard (Part 1926, Subpart T) was written and adopted decades ago in order to address the employment hazards we may expect to find during disassembly of a structure or building. In the case of most roof/floor demolition practices, many contractors must place personnel on the very structures they are in the process of removing or disassembling. As cut-off, levering and impact forces are applied to their work supports, fasteners release, materials separate, and live and dead load vectors must change routes instantaneously through other members capable of gravitational resistance somewhere below them. If these materials, in turn, fail and release, the domino effect of a pancake collapse may occur. Sometimes an abrupt arrest of a collapsing member is all it takes to either crush a worker within or eject him from the structure.

According to 1926.850(a), contractors are responsible for inspecting and analyzing the structures they are about to demolish: “Prior to permitting employees to start demolition operations, an engineering survey shall be made, by a competent person, of the structure to determine the condition of the framing, floors, and walls, and possibility of unplanned collapse of any portion of the structure. Any adjacent structure where employees may be exposed shall also be similarly checked. The employer shall have in writing that such a survey has been performed.”

I realize that the scope of this particular regulation may seem excessive for many small roofing contractors to comply with, but its purpose and application is certainly well intended. We can all admit that many more roofers fall off of the eaves and rakes than fall through the decking of an old roof. However the Bureau of Labor Statistics notes that the recent number of employees falling through roof openings and failures are dramatically on the rise. Even if only 1 in 10,000 roofers potentially falls through the roof to their deaths, I don’t believe anyone would willingly volunteer to be that next fatality.

Troubleshooting and Repair

Not all roofing contractors also provide roof framing/sheathing repair or replacement services to their clients. They may subcontract this portion of the work to others or require their client (the property owner or prime contractor) to correct the situation before they repair the waterproofing. In the General Safety And Health Provisions section (1926.20(a)(1), OSHA states, “no contractor or subcontractor for any part of the contract work shall require any laborer or mechanic employed in the performance of the contract to work in surroundings or under working conditions which are unsanitary, hazardous or dangerous to his health and safety.”

It may seem, at first, to be illogical that a roofing contractor would voluntarily spend the cost of materials, labor and equipment costs to actually rebuild, shore up, cross brace or “sister” decayed or cracked rafters, or oversheath a section of rotten deck upon which he will be required to work unless required by the terms of the contract. And yet, OSHA requires the roofing employer to investigate the substructure “prior to permitting employees to start demolition operations.”

The standard goes on to state in 1926.850(b):“When employees are required to work within a structure to be demolished which has been damaged by fire, flood, explosion, or other cause, the walls or floor shall be shored or braced.”

According to most of the compliance officers I’ve asked, the regulatory on-site intent of this standard may assume that “within” also implies “upon” as well. The term “other cause” would certainly include water and impact damage to roofs, potentially allowing water infiltration and decay. The structural integrity of walking/working surfaces to support those who must make access is also guaranteed under the Duty to Provide Fall Protection (1926.501(a)(2): “The employer shall determine if the walking/working surfaces on which its employees are to work have the strength and structural integrity to support employees safely. Employees shall be allowed to work on those surfaces only when the surfaces have the requisite strength and structural integrity [to support them].”

OSHA defines a hole as “a gap or void 2 inches or more in its least dimension in a floor, roof or other walking/working surface.” While OSHA does not specifically stipulate that a hole must be visible to be a hole, it obviously must be capable of being measured. Many roof deck holes can be observed when the attic or below-roof void may be physically accessed for inspection. While not always a comfortable proposition, as a draftsman, contractor and building inspector, I have crawled and slithered many miles in attics and crawlspaces and underneath roof pitches to inspect materials, measure dimensions and investigate water and insect damage. Whenever I have made assumptions concerning unseen conditions without verification, I’ve lived to regret it. Without such available access, a roof surface suspected of damage may be carefully “sounded” by using dropping the flat surface of a sledge head 6 inches onto the roof area ahead to approximate the impact area and force of a foot fall. Once a dead zone is sounded, I may cut and strip away the roofing and underlayment to further inspect the deck and possibly the rafters/trusses. This may appear to some to be a colossal waste of time, but would certainly be a minimum pre-bid procedure if you suspect the roof to be in less-than-acceptable condition. Applying new roof shingles over poor condition substrates not only jeopardizes your roofers in the worst case, it invites expensive callbacks at the least.

The Fall Protection Standard goes on to state in section 1925.501(b)(4)(I) and (ii): “Each employee on walling/working surfaces shall be protected from falling through holes, (including skylights) more than 6 feet above lower levels. … Each employee on a walking/working surface shall be protected from tripping in or stepping into or through holes (including skylights) by covers.”

OSHA stipulates that these covers shall be capable of resisting two times the maximum intended loads potentially applied to them. As we can deduce, if a roofer falls partially or totally through any roof surface, it would have been the employer’s obligation to have prevented the fall from occurring, protected the employee from the effects of the fall, or removed the employee from the exposure area until the fall hazard has been totally abated.

When the competent person decides that covering a hole during demolition is either infeasible or creates a greater hazard, he may either build a compliant guardrail system around the hole or select and design a personal fall arrest system (PFAS) to protect his demolition crew. Guardrails on objects slated for demolition prove ineffective eventually. The only problem with PFAS on a demolition job is that the scope of work often includes physically removing, or reducing the strength of, members previously selected as PFAS anchor points. It may be hours or days before another suitable anchor point will be installed and evaluated by a qualified person as capable of withstanding a 5,000-pound force per attached worker. There may be times when the only feasible method of roof demolition fall prevention is the implementation of a safety monitor system within a clearly established controlled access zone (CAZ). As this is only an administrative level hazard control, it should not be used for the sake of convenience, speed or cost, but only in limited application for short periods where no other system will prove as effective or safe.

In the case of most roof/floor demolition practices, many contractors must place personnel on the very structures they are in the process of removing or disassembling. (Photo courtesy of Evans Roofing Company.)


You may think you have a bomb-proof indemnity clause in your boiler-plate contract capable of releasing you from loss and liability for “unseen conditions,” but being responsible for making reasonable efforts to detect “unseen conditions” under the OSHAct may be seen as your minimum legally binding obligation in a court of law. But the truth remains that contracts cannot negotiate out OSHA-mandated employer obligations. Federal OSHA standards are the minimum labor safety laws of the land. As a safety consultant, my advice to my clients is that the best time to take any evasive action is never during trial proceedings but always before your employees become hazardously exposed. The first method never works, while he second one always prevails. As an integral part of your site-specific safety and health program, a thorough and well documented pre-demolition engineering survey falls into the GFE (good-faith effort) category of employer defense strategies. It’s been my experience that GFEs always stand up well to attack in a jury trial. Like almost all the safe work practices I’ve recommended over the years in Roofing Contractor, instructing your competent person to conduct a written structural engineering review of each roof you are planning to access for material removal is just a good business decision.

Surveys will become easier and quicker to conduct and therefore less costly over time. Under certain conditions, some states include the property owner/builder in the list of potential controlling employers in workplace accident cases. Not only is it a professional courtesy to offer a copy of your signed and dated engineering survey to the property owner, it may also serve as a “binding, written notification of hazardous conditions” to the host employer in the chain of responsibility. In some states, that adds an equal, legal “burden of control” on the property owner/project manager/owner’s representative to take prompt actions to correct the unsafe conditions which you discovered in your ES. The defective items you discover below the decks you’ll eventually occupy will continually amaze you. After completing an ES, your bids may reflect your ability to foresee costly problems before you submit a total lump sum proposal for work. I was told a trade secret many years ago by a successful injury trial attorney: “The guy with the most paperwork doesn’t usually win. He always wins.”

Taking the time and effort to conduct and compile a competent engineering survey of a roof on which you are planning selective demolition might just pay off in ways you’ll never expect.