Removal of Asbestos Roofing
Removal of asbestos roofing is a high-hazard exterior remediation operation involving the safe extraction and disposal of corrugated transite cement panels, imitation slate shingles, and bituminous roof felts installed prior to the mid-1980s. Because decades of weathering and lichen growth erode the outer cement binder, roof abatement requires specialized fall protection, continuous surfactant misting, and non-destructive manual unfastening to prevent catastrophic fiber release.
The Architectural Forms and Aging Characteristics of Asbestos Roofs
Between 1910 and 1980, asbestos roofing assemblies were heavily utilized on commercial warehouses, industrial mills, agricultural barns, and residential dwellings. Prized for their non-combustible ratings and resistance to rot, two primary product lines dominated: corrugated transite panels and pressed asbestos-cement shingles.
Corrugated transite consists of Portland cement reinforced with fifteen to twenty-five percent chrysotile or crocidolite asbestos fibers pressed into rigid, wavy sheets. While exceptionally durable, decades of ultraviolet solar radiation, freeze-thaw cycles, and acid rain gradually leach the alkaline cement binder, exposing loose microscopic fibers on the exterior surface.
| Roofing Material Type | Material Composition | Expected Lifespan | Friability & Disturbance Hazard |
|---|---|---|---|
| Corrugated Transite Sheets | Portland cement & 15% to 25% chrysotile/crocidolite | 50 to 80+ Years | Non-friable Category II (Friable if sawed, cracked, or crushed) |
| Asbestos-Cement Shingles | Pressed cement slate substitute (15% to 30% asbestos) | 40 to 60 Years | Non-friable Category II (High hazard during power saw cutting) |
| Asphalt-Saturated Roofing Felts | Organic felt paper infused with asphalt | 20 to 30 Years | Non-friable Category I (Flexible when intact) |
| Coal Tar Pitch Built-Up Roofs | Multiple plies of felt and tar gravel | 20 to 30 Years | Non-friable Category I (Pulverized during mechanical tear-offs) |
Safety Protocols: Fall Protection and Non-Destructive Extraction
Removing asbestos roofing presents dual hazards: catastrophic fall risks and hazardous fiber inhalation. Aged transite panels become brittle with time; walking directly on corrugated sheets often leads to sudden panel fractures and fatal falls through the roof deck into the building interior.
Crews must utilize crawling boards, roof ladders, and full-body fall arrest harnesses anchored to structural purlins. Power saws, abrasive cutting wheels, and mechanical drop hammers are strictly illegal under EPA NESHAP regulations. Every panel must be unfastened manually using hand wrenches or low-speed drill drivers to back out drive screws without shattering the brittle cement matrix.
| Operational Step | Required Tooling & Equipment | Critical Safety Function | Regulatory Safety Violation to Avoid |
|---|---|---|---|
| Access & Fall Protection | Crawling boards, full-body harness, lifeline | Spreads weight across purlins; prevents falls through deck | Walking directly on corrugated sheets |
| Surface Wet Suppression | Low-pressure airless garden sprayer | Saturates weathered cement to bind loose fibers | High-pressure power washing (strictly illegal) |
| Manual Fastener Removal | Hand wrenches, low-speed screw extractors | Backs out lag bolts without shattering panels | Using circular saws or reciprocating saws to cut sheets |
| Ground Lowering System | Crane sling, enclosed debris chute, pallet lift | Lowers panels gently to ground without breakage | Dropping or throwing shingles from roof deck |
| Hazardous Waste Packaging | Double-layered 6-mil poly sheets, duct tape | Hermetically wraps bundles with OSHA warning labels | Dumping loose panels into open construction dumpster |
Panels must never be dropped or tossed from the roofline into ground dumpsters. Impact with the ground shatters the brittle cement, blasting clouds of carcinogenic dust across the property. Instead, technicians lower panels in padded slings or hoist baskets directly onto pallets wrapped in heavy 6-mil plastic.
Upon completing roof panel removal, the bare timber purlins and roof deck must be HEPA vacuumed and sprayed with a clear acrylic lockdown encapsulant before new standing-seam metal or asphalt shingle roofing is installed.
How to Safely Remove Asbestos Roofing Assemblies
Standard operating procedure for the professional containment and removal of asbestos roof panels.
Establish Fall Arrest and Crawling Boards
Erect scaffolding, attach full-body harnesses to certified ridge anchors, and lay crawling boards across roof purlins to avoid stepping on brittle panels.
Mist Shingles with Surfactant Solution
Spray panels continuously with water mixed with wetting surfactant at low pressure (< 50 psi) to suppress loose surface fibers.
Manually Back Out Fastener Screws
Use hand socket wrenches or low-speed drill drivers to carefully remove lag bolts and nails without snapping panel edges.
Lower Panels Intact via Crane or Hoist
Stack intact panels onto wooden pallets, lower them to the ground using crane slings or lift hoists, and double-wrap them in 6-mil plastic.
Apply Lockdown Encapsulant to Roof Purlins
HEPA vacuum the exposed timber purlins, apply a clear acrylic lockdown spray to bind residual dust, and manifest waste for certified landfill burial.
Frequently Asked Questions (7 Questions Answered)
Q1: Can I remove an asbestos roof myself?
DIY removal of asbestos roofing is dangerous due to fall hazards and illegal in many areas due to strict environmental fiber emission laws.
Q2: Can you walk on an asbestos roof?
Never walk directly on an asbestos roof; vintage transite panels are brittle and can snap under human weight, resulting in fatal falls.
Q3: Can you cut asbestos roof sheets with a circular saw?
Never use power saws on asbestos cement; high-speed blades shatter the panels and blast clouds of toxic dust into the neighborhood.
Q4: How much does it cost to remove an asbestos roof?
Professional removal typically costs between $8 and $16 per square foot, including scaffolding, labor, crane hoists, and disposal fees.
Q5: Can I put a new metal roof over an asbestos roof?
Yes, installing furring strips and an over-roof metal sheet system over intact asbestos shingles is an approved, safe encapsulation method.
Q6: Where do contractors dispose of asbestos roofing panels?
Bundles wrapped in 6-mil plastic are transported under hazardous waste manifests to state-licensed landfills permitted to receive asbestos.
Q7: What protective equipment is required for roof removal?
Workers must wear NIOSH-approved P100 respirators, disposable Type 5/6 coveralls, rubber work boots, and full-body fall arrest harnesses.
Final Thoughts & Key Takeaways
The removal of asbestos roofing demands disciplined adherence to fall protection and non-destructive extraction methods. Never walk directly on brittle transite sheets or use power saws to cut panels. By utilizing crawling boards, low-pressure surfactant misting, manual fastener extraction, and manifested hazardous landfill disposal, licensed abatement contractors ensure safe, compliant roof replacement.