Pre-Access Hazard Assessment
Before anyone goes up, assess conditions from the ground. This 10-minute check prevents the majority of rooftop accidents.
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Check weather conditions — no work on wet, icy, or frost-covered roofs
Wet or icy roofing surfaces reduce traction by 50–80%. Frost is especially dangerous because it's often invisible in early morning. Check the roof surface temperature — if it's at or below 32°F and there's any moisture, the surface may be icy even if it doesn't look it. Wind above 25 mph creates fall risk on any roof, even when dry.
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Identify all roof edges, skylights, and openings that present fall hazards
Walk the perimeter from the ground and note every unprotected edge, skylight, roof hatch, vent opening, and areas where the roof changes level. Each one needs fall protection — guardrails, covers, or personal fall arrest systems. Skylights are particularly dangerous because they look solid but most residential skylights cannot support a person's weight.
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Assess the structural condition of the roof before loading it with workers and materials
Look for visible sag, bounce when walked on, soft spots, or signs of fire or water damage that may have weakened the structure. An older roof being prepared for tear-off may have rotted decking that gives way under foot traffic. If there's any doubt, have a structural assessment done before loading the roof with workers, material pallets, and equipment.
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Locate all overhead electrical lines within 10 feet of the roof edge or work area
Contact with overhead power lines is fatal. Identify every wire within 10 feet of the roof perimeter, including service drops to the building. Ladders, metal gutters, and long pieces of flashing or drip edge can contact lines when lifted or swung. If lines are within the work zone, call the utility company to install protective covers or de-energize the line before work begins.
Ladder Safety
Ladder falls account for a significant percentage of roofing injuries. Inspect every ladder before each use and set it up correctly.
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Inspect the ladder for damage — bent rails, cracked rungs, missing feet
Check every rung for cracks, bends, and looseness. Verify that the feet (shoes) are present and in good condition — missing or worn feet cause the ladder base to slide. Check locking mechanisms on extension ladders to ensure they engage fully. Never use a damaged ladder — tag it out and remove it from the job site.
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Set up the ladder at the correct angle — 1 foot out for every 4 feet of height
The 4:1 rule prevents both the base from sliding out (too steep) and the ladder from tipping backward (too shallow). For a roof edge at 12 feet, the base should be 3 feet from the wall. The top of the ladder must extend at least 3 feet above the roof edge to provide a handhold when stepping on and off.
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Secure the ladder at the top and bottom
Tie the top of the ladder to a secure anchor point (roof joist, fascia board with a standoff bracket, or a ladder stabilizer). Place the base on firm, level ground — never on soft soil, gravel, or uneven surfaces without a leveler. If the ground is soft, use a wide base pad. Never place a ladder on another object (bucket, box, truck bed) to gain height.
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Maintain three points of contact when climbing — two hands and one foot, or two feet and one hand
Carry tools in a belt or bucket, not in your hands. Never lean sideways past the ladder rails — if your belt buckle extends past the rail, you're over-reaching. Climb down and reposition the ladder instead.
Fall Protection Equipment
OSHA requires fall protection for any work 6 feet or more above a lower level. On residential roofing, personal fall arrest systems are the most common solution.
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Inspect harnesses for wear, cuts, fraying, and damaged stitching before each use
Check all webbing for cuts, abrasion, UV degradation (stiffness, discoloration), and chemical damage. Verify that all buckles and D-rings are free of cracks and corrosion. Check stitching at all connection points for broken threads. A harness that has arrested a fall must be retired — the forces involved stretch and weaken the materials even without visible damage.
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Verify anchor points are rated for 5,000 lbs per worker or designed by a qualified person
Roof anchors must be attached to structural members (rafters, trusses) — never to decking, fascia, or sheathing alone. Temporary roof anchors cost $20–$50 and fasten through the deck into the rafter with lag screws. Permanent anchors should be sealed and flashed into the roofing system.
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Confirm lanyards and self-retracting lifelines are in working order
Check that snap hooks close and lock fully. Test self-retracting lifelines by pulling a few feet of cable and verifying it retracts smoothly and locks when pulled sharply. Verify the lanyard length keeps the fall distance within safe limits — a 6-foot lanyard with a 3.5-foot deceleration distance requires at least 18.5 feet of clearance below the anchor point to prevent ground contact.
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Install guardrails or warning lines on flat or low-slope roofs as an alternative to harnesses
On flat or low-slope roofs, guardrails at roof edges (42 inches high with mid-rail and toe board) or warning lines (set back 6 feet from the edge) provide fall protection without the mobility restrictions of a harness and lanyard. Guardrails are required on commercial jobs and recommended on residential flat roofs.
On-Roof Hazard Management
Once on the roof, continuous hazard awareness prevents injuries from falls, tools, and materials.
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Cover all skylights and openings with material rated for the expected load
Skylights are fall-through hazards — most residential skylights shatter under body weight. Cover them with ¾-inch plywood screwed into the curb or framing, or install a skylight cage. Mark the cover clearly: 'HOLE — DO NOT REMOVE.' Never place tools, materials, or feet on a skylight dome.
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Keep the work area clear of loose tools, debris, and coiled cords
Trip hazards on a roof surface are fall hazards. Stage tools in a designated area, keep air hose and extension cords routed along a consistent path, and clear tear-off debris continuously rather than letting it pile up. Use tool lanyards on anything that could slide off the roof and hit someone below.
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Establish a ground-level exclusion zone below all roof edges
No one should walk, stand, or park below an active roof work area. Falling tools, debris, and shingle bundles can cause serious injury. Mark the exclusion zone with cones, tape, or barricades — extend it at least 6 feet out from the roof edge, farther on multi-story buildings.
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Monitor weather changes throughout the work day
A clear morning can turn into afternoon thunderstorms. Assign someone to check weather radar hourly. Descend from the roof before lightning moves within 10 miles (if you hear thunder, you're within 10 miles). Stop work if rain starts — wet roofs become dangerous within minutes as water mixes with granule dust.
Pro Tips
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Do a 2-minute safety briefing at the start of every work day
Before anyone goes up, the crew lead takes 2 minutes to identify that day's specific hazards — weather, structural concerns, overhead lines, and any changes from the day before. This single practice reduces roofing injuries by addressing the hazards workers are most likely to encounter that specific day.
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Keep a first aid kit and a phone at the roof access point
In an emergency, the difference between having supplies at the ladder base vs. in the truck can matter. Keep a stocked first aid kit and a charged phone (with emergency contacts visible) at the primary access point. If someone is injured on the roof, the person giving aid shouldn't have to leave the roof to call for help.
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Homeowners: hire only roofers who demonstrate safety practices
A roofing crew that shows up without harnesses, sets ladders at wrong angles, and has no exclusion zone below the work area is telling you how carefully they do everything. If they cut corners on safety (which affects their own lives), they'll cut corners on your roof. Licensed, insured roofers with visible safety equipment are worth the premium.
Common Mistakes to Avoid
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Assuming the roof is dry because it hasn't rained
Dew, frost, and condensation make roofs slippery without any rainfall. Early morning surfaces can be as slick as a wet roof. Wait until the sun has dried the surface — typically 1–2 hours after sunrise depending on season and exposure.
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Using fall protection gear that has arrested a previous fall
After a fall arrest event, the harness, lanyard, and anchor have absorbed significant force. The materials are stretched, stressed, and may have invisible damage. Retire all components that have arrested a fall, even if they look undamaged. The cost of replacement ($50–$400) is negligible compared to the cost of equipment failure.
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Setting up ladders on the wrong surface
Ladders placed on wet grass, loose gravel, soft soil, or uneven pavement slide at the base — the most common ladder failure mode. Use a ladder leveler on uneven ground, a base pad on soft ground, and never set up on ice or standing water.
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Rushing the last hour of the work day
The majority of roofing falls happen in the last 1–2 hours of the work day when workers are fatigued, rushing to finish, and taking shortcuts with fall protection. Maintain full safety protocols until the last person is off the roof — no exceptions for 'just one more task.'