Date Posted: 05/29/2024

Roofing work can be dangerous even under the best conditions. High elevations, unprotected roof edges, and steep slopes pose fall risks. Those risks may be increased by other factors, such as wind and wet surface, equipment misuse or failure, particularly involving ladders, and unsafe behavior on the part of workers. Washington Department of Labor and Industries, Division of Occupational Safety and Health (DOSH) defines the standards for different types of roof slopes and safety requirements for each type. Falls are the leading cause of private-sector work deaths in the construction industry, accounting for nearly 40 percent of worker fatalities, according to the Division of Occupational Safety and Health (DOSH).

Roofing Work vs. Non-Roofing Work

WAC 296-880-095 defines roofing work as “The hoisting, storage, application, and removal of roofing materials and equipment, including related insulation, sheet metal, and vapor barrier work, but not including the construction of the roof deck.” Roofing work may occur on either a low-pitch or steep-pitch surface.

Low Pitch Roofs

A low-sloped roof is defined as a slope equal to or less than a ratio of 4 to 12. The slope is calculated by rise over run. Thus, a low-sloped roof is a roof where for every 12 units (inches, feet, or meters) measured horizontally (Run), the roof does not increase or decrease by more than four units vertically (Rise).

According to WAC 296-880-20005, for fall protection on low-pitched roofs, workers exposed to fall hazards of four feet or more while engaged in work other than roofing work, construction, or leading edge must use a personal fall restraint system, personal fall arrest system, positioning device system, warning line system, or standard guardrail system. A low-slope roof is defined as one with a slope less than or equal to 4/12. If the slope of the roof you are working on has a slope greater than 4/12, a different fall protection system must be utilized.

Note: Unless specifically addressed in the WAC standards, employers must ensure that a fall arrest system, fall restraint system, or positioning device system is provided, installed, and implemented in accordance with WAC 296-880-400 (Fall protection system specifications) when employees are exposed to fall hazards of six feet or more to the ground or lower level while engaged in roofing work or constructing a leading edge on a low pitched roof.
Exception: Employees not directly involved with constructing the leading edge or are not performing roofing work must comply with the requirements of WAC 296-880-200.

Steep Pitch Roofs

WAC 296-880-095 defines a steep pitch roof as “a roof having a slope greater than four in 12 (4:12).” Fall protection on steep-pitched roofs. Regardless of the work activity, the employer must ensure that employees exposed to fall hazards of four feet or more while working on a roof with a pitch greater than four in 12 use a fall restraint system, a personal fall arrest system, or a positioning device system.

Note: According to WAC 296-880-20005(6)(a), a safety monitor system is prohibited on steep-pitch roofs.

Warning Lines

A warning line system is a flagged line set up around the perimeter of a roof designed to alert workers that they are approaching an unprotected edge. WAC 296-880-095 defines an unprotected edge as “Any open side or edge of a floor, roof, balcony/deck, platform, ramp, runway, or walking/working surface where there is no standard guardrail system, or parapet wall of solid strength and construction that is at least 39 inches in vertical height.” There is no “safe” distance from an unprotected side or edge that would render fall protection unnecessary. This means that even if workers are working in the center of a roof 100 feet in width, they must still be protected from falling in some manner. Warning lines can only be used on low-sloped roofs.

Warning lines must be established before work begins.
Warning lines must be set up around all sides of the work area.
Warning lines/flags must be flagged with a highly visible material, and spacing must not exceed 6-foot intervals.
Points of access, materials handling, storage, and hoisting areas must be connected to the work area by an access path formed by two warning lines.
Warning lines must be set up at least 6 feet from the roof’s edge.
If using mechanical equipment, the warning lines must be set up at least 10 feet from the roofing edge.
When working outside of the warning lines, one of the following additional fall protection systems must be utilized:
- Fall Restraint
- Personal Fall Arrest
- Guardrail
- Safety Monitor
All workers must be trained.

What is a Parapet, and When is One Sufficient for Fall Protection?

A parapet wall is a low or dwarf wall built along the edge of the roof, terrace, walkway, balcony, etc. Parapet walls can be constructed using reinforced cement concrete, steel, aluminum, glass, etc. To function as adequate fall protection, parapet walls must be of sufficient strength and at least 39” high, or roof fall protection must be provided.

A scaffolding is shown with guardrails used as fall protection.

Hole Covers

A cover includes any rigid object overlaying openings in floors, roofs, and other walking and working surfaces. Covers must support at least twice the maximum anticipated load of workers, equipment, and materials. Covers should have a full-edge bearing on all four sides. Make sure covers are secure and color-coded, or mark them with the words “HOLE” or “COVER.”