Repairs Required Before Coating

Define the Repair Scope Before Mobilization

Use the roof-condition assessment, moisture survey, test openings, adhesion testing, manufacturer review, and project drawings to prepare a repair plan. Mark repair areas on the roof and on a dimensioned roof plan.

• Identify wet-area removal and replacement boundaries.
• Separate measured repair quantities from allowances and unit-price work.
• Assign responsibility for structural deck, sheet metal, mechanical equipment, drains, masonry, and electrical work.
• Identify manufacturer-required detail materials, primers, reinforcement, cure times, and recoat windows.
• Establish repair inspection hold points before primer or field coating hides the work.
• Provide a procedure for concealed conditions discovered during opening or cleaning.

Repair Requirements by Existing Roof Type

Single-Ply Membranes

• Repair open, fish-mouthed, wrinkled, or failed seams using membrane-compatible materials and procedures.
• Cut out or properly repair punctures, splits, burns, unsupported membrane, and deteriorated flashings.
• Remove incompatible mastics, tapes, coatings, and temporary patches that cannot provide a stable substrate.
• Address membrane shrinkage, bridging, tenting, stress at penetrations, and pulled terminations.
• Do not rely on roof coating to weld a failed thermoplastic seam or rebuild a failed EPDM splice.

Built-Up and Polymer-Modified Bitumen Roofing

• Repair splits, open laps, blisters selected for correction, bare felts, displaced surfacing, and deteriorated flashings.
• Remove loose aggregate and unstable or oxidized material as required by the approved system.
• Cut and repair defects using compatible bituminous or manufacturer-approved liquid-applied details.
• Evaluate asphalt bleed-through and use the specified bleed-blocking primer or system where required.
• Do not coat loose granules, poorly bonded flood coat, or soft and unstable asphalt.

Metal Roof Systems

• Replace missing, loose, backed-out, stripped, or severely corroded fasteners with approved fasteners and washers.
• Repair loose laps, failed sealant, open end laps, ridge details, closures, gutters, curbs, and penetrations.
• Replace metal that is perforated, structurally weakened, or too thin to support a durable repair.
• Remove loose corrosion and prepare remaining metal to the specified condition before applying rust-inhibitive primer.
• Allow for thermal movement. Do not rigidly bridge a designed moving seam with an unsuitable repair.

Spray Polyurethane Foam Roofing

• Remove wet, friable, UV-degraded, poorly adhered, blistered, crushed, or contaminated foam.
• Cut repairs back to sound, dry foam and rebuild with compatible roofing foam or the approved repair system.
• Shape repairs to drain and avoid sharp edges, voids, birdbaths, and abrupt transitions.
• Protect newly exposed or installed foam from ultraviolet exposure and moisture within the manufacturer's required time.
• Do not fill deep foam loss with field coating or surface mastic alone.

Concrete and Cementitious Substrates

• Remove unsound concrete, laitance, weak repairs, curing compounds, coatings, and contaminants that interfere with adhesion.
• Repair spalls, voids, honeycombing, cracks, and deteriorated penetrations using compatible materials.
• Distinguish moving joints from nonmoving cracks. Moving joints require an engineered flexible detail—not rigid filling.
• Correct active water entry, rising moisture, and substrate moisture conditions before membrane application.

Drains, Scuppers, and Gutters

Drainage details must remain open, serviceable, and securely integrated with the roof system.

• Remove debris and verify that drains, scuppers, overflows, gutters, and leaders flow freely.
• Repair broken strainers, loose clamping rings, corroded bowls, failed sumps, open joints, and deteriorated conductor heads.
• Rebuild the membrane-to-drain transition using the approved reinforced or clamped detail.
• Correct raised drains and low-area defects through approved drainage work—not excessive mastic.
• Keep primary and overflow openings at their required dimensions and elevations.

Penetrations, Curbs, and Rooftop Equipment

Round pipes, irregular penetrations, conduit clusters, equipment legs, curbs, ducts, pitch pockets, skylights, hatches, supports, and abandoned openings require individual details. One generic bead of sealant is rarely an adequate repair strategy.

• Secure loose components and replace missing counterflashing, storm collars, closures, or fasteners.
• Raise low curbs or penetrations when required for the approved flashing height.
• Remove abandoned equipment and close openings with a structurally and watertight approved assembly.
• Repair leaking HVAC equipment, condensate lines, process piping, and grease or chemical discharge sources.
• Use reinforced liquid flashing, compatible boots, penetration pockets, or sheet details exactly as specified.
• Do not coat moving mechanical parts, service panels, labels, weep openings, electrical components, or removable covers.

Perimeters, Walls, and Terminations

Roof edges experience high wind forces and frequent movement. Repair loose or corroded edge metal, open coping joints, failed counterflashings, deteriorated termination bars, cracked masonry, and separated wall transitions before coating.

Confirm the intended termination height and method. Liquid-applied material should end at an approved termination—not feather out randomly onto masonry, siding, glazing, or equipment. Masonry cracks, wall leaks, coping defects, and facade water entry may require work outside the roof coater's scope.

Sealants, Mastics, Tapes, and Old Patches

Existing repairs must be evaluated individually. Weathered silicone, asphalt mastic, plastic cement, urethane sealant, butyl tape, acrylic patching, and unknown materials can create adhesion or compatibility problems.

Follow Published Details by Number

A complete manufacturer manual may provide different details for ribbed, corrugated, standing-seam, and structural-panel seams as well as separate details for roof edges, walls, equipment curbs, skylights, joints, pipes, penetration pockets, and drains.

For example, the GAF Liquid-Applied Roofing Manual, Version 2.2, identifies detail families including LAR-106 seam flashings, LAR-202 edge fascia, LAR-302 wall flashing, LAR-303 equipment curbs, LAR-307 skylight curbs, LAR-309 HVAC curbs, LAR-401 concrete control joints, LAR-503 pipe flashings, LAR-506 penetration pockets, and LAR-510 reinforced drains.

These are useful examples of detail specificity; they apply only when the selected GAF system and current project requirements authorize them.

Repair Materials Must Cure Before Coating

Observe minimum and maximum overcoat times for sealants, primers, mastics, foam, repair membranes, concrete materials, and liquid flashing. A repair that feels dry on top may still contain solvent, water, or reactive components beneath the surface.

Record product, lot number, mixing ratio, application time, weather, substrate temperature, dew point, cure time, and inspection result. When the recoat window is exceeded, perform the required cleaning, abrasion, solvent wipe, primer, or other manufacturer procedure before continuing.

Repair Acceptance Hold Point

Before field primer or coating is applied, inspect and document:

1. Wet and damaged materials have been removed to confirmed sound boundaries.
2. Replacement components match the approved assembly and attachment.
3. Seams, fasteners, cracks, joints, penetrations, curbs, drains, edges, and transitions use approved details.
4. Repairs are fully bonded, cured, dry, smooth enough to coat, and free of voids, fish mouths, pinholes, and sharp edges.
5. Drainage paths and overflow openings remain unobstructed.
6. Repair materials are compatible with the primer and field coating.
7. Required manufacturer or design-professional inspection has occurred.
8. Photographs, quantities, test results, and concealed-condition changes are recorded.

Technical References

• NRCA Guidelines for Roof Coating Applicators, 2026—Best-practice recommendations for substrate evaluation, repairs, preparation, coating selection, and application.
• NRCA Guidelines for Roof Coatings, updated 2026—Evaluation, preparation, application, and on-site quality-control guidance.
• GAF Liquid-Applied Roofing Manual, Version 2.2—Manufacturer example covering moisture surveys, damaged-substrate treatment, substrate preparation, seam treatment, and numbered detail drawings.
• Spray Polyurethane Foam Alliance Technical Documents—Industry resources for spray polyurethane foam roofing, maintenance, repair, and protective coatings.

Application rule: Use the current project specification, approved manufacturer details, product data sheets, safety data sheets, repair procedures, code requirements, and written warranty terms. The named manufacturer details are educational examples, not endorsements or universal details.