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Commercial roof replacement for multi-site businesses

A commercial roof replacement removes the existing roof system down to the deck and installs a new one under a building permit. Facility First manages the assessment, approvals, provider dispatch and close-out records for each location.

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What commercial roof replacement involves

Commercial roof replacement is the full removal of an existing roof system down to the roof deck and the installation of a new one. The reroofing provisions of the International Building Code (Section 1512 in the 2024 edition) treat replacement and recover separately. A recover installs a new covering over the existing one and is allowed only in limited conditions.

A low-slope replacement usually includes:

A survey of the deck, drains, rooftop equipment and existing layers, with asbestos sampling of suspect materials
Permit drawings that state the insulation type, thickness and R-value
Tear-off in sections, with the building kept watertight at the end of each work period
Deck repair, new insulation (often tapered for drainage), cover board, membrane, flashings and edge metal
Disconnection and reset of rooftop equipment, coordinated with the HVAC provider
Inspections, close-out photos and warranty registration

A moisture survey belongs in the scope. Infrared thermography, nuclear meters or capacitance meters locate retained moisture, and core cuts confirm the findings. Wet materials can cause premature deterioration even when the roof looks sound, and decks often deteriorate where moisture is retained.

Codes and requirements for commercial roof replacement

Each jurisdiction adopts its own code editions and amendments, and the local building official decides what applies to a given building.

When a recover is not allowed. The model code language, as adopted in California’s 2025 building code, does not permit a recover when the existing roof is water-soaked or deteriorated to the point that it is not an adequate base, when the existing covering is slate, clay, cement or asbestos-cement tile, or when the roof already has two or more applications of any type of roof covering. In those cases the roof must be replaced.

Drainage. The 2024 IBC reroofing exceptions allow positive drainage in place of the one-quarter inch per foot minimum slope and waive secondary (emergency overflow) drainage, but ponding instability must then be evaluated under Sections 1608.3 and 1611.3. Tapered insulation is one accepted way to reach the minimum slope. California’s adopted text also states that existing secondary drains or scuppers cannot be removed unless they are replaced with compliant ones.

Materials that cannot be reused. Existing building code provisions (California Existing Building Code Section 705.4, for example) bar reinstalling vent flashing, metal edgings, drain outlets, collars or metal counterflashings that are rusted, damaged or deteriorated, and bar reinstalling aggregate surfacing from built-up roofs.

Energy code insulation. A replacement can trigger new-construction insulation levels. Philadelphia’s guidance on the 2018 IECC (Section C503.3.1) requires replacement insulation on roofs insulated entirely above the deck to meet new-construction requirements, and accepts parapet heights, equipment curbs, window sills and door thresholds as reasons added thickness may be technically infeasible. Columbus, Ohio, requires insulation to reach at least R-30 on commercial reroofing of modified bitumen, built-up or membrane roofs where the existing insulation or deck is exposed, with an inspection before the insulation is covered.

Asbestos. Under EPA’s interpretive rule for roof removal (40 CFR Part 61, Subpart M, Appendix A), suspect roofing should be tested. Nonfriable asphalt roofing removed by slicing or manual tools is not covered by the asbestos NESHAP; removal of Category I nonfriable material with rotating blade cutters is covered once the project reaches 5,580 square feet. Covered projects require written notice at least 10 working days in advance and waste shipment records kept for at least 2 years. Other state and local rules may also apply.

Fall protection. OSHA 29 CFR 1926.501(b)(10) sets the fall protection rule for roofing work on low-slope roofs. OSHA’s interpretation allows warning lines 6 feet (and in some cases 10 feet) back from the edge, combined with safety monitors, in place of guardrails or personal fall arrest systems.

Preventive maintenance schedule for commercial roofs

Planned maintenance means fewer emergency leak calls, a longer service life before the next replacement and a record that supports warranty claims and the next replacement decision.

Task	Recommended frequency	Basis
Inspect the roof system, including membrane, seams, flashings and edge metal	At least twice a year, spring and fall	National Roofing Contractors Association (NRCA)
Inspect after severe weather such as hurricanes, tornadoes or hailstorms	After each event	NRCA
Clear drains, scuppers and gutters of debris	At each scheduled inspection	Facility First program default, adjusted per site
Check curbs, penetrations and flashings after rooftop equipment service	After each rooftop service visit	Facility First program default, adjusted per site
Complete inspections and maintenance required to keep the roof warranty in force	As the warranty terms state	Manufacturer instructions
Run a moisture survey with core cuts to confirm findings	When inspections or leak history point to wet insulation	Facility First program default, adjusted per site
Update the roof plan, photos and repair log	At every visit	Facility First program default, adjusted per site

The authority having jurisdiction, the roof manufacturer and the property’s insurer can require more frequent service, and each location’s schedule is set in its program and recorded on every visit.

Signs a roof needs replacement rather than repair

Large areas of wet insulation, where repairs may not be cost-effective
Two or more existing roof coverings, which rules out a recover
Deteriorated or corroded deck found at core cuts or during repairs
Leaks returning in different areas after repeated repairs
Widespread membrane, seam or flashing deterioration rather than isolated damage

A commercial roof inspection program builds the condition history behind a replacement decision. Isolated damage is usually handled as flat roof repair or TPO roof repair. See the facility condition assessment guide.

Records to keep

Building permit, approved drawings, inspection sign-offs and final approval
Insulation type, thickness and R-value, with the insulation inspection record where required
Asbestos sampling results and, for covered work, notification and waste shipment records
Moisture survey report and core cut results
Manufacturer warranty, registration and the roof plan as installed
Daily photos of tear-off, deck condition and each dry-in

How Facility First runs commercial roof replacement across a portfolio

Assessment. Inspection history, leak records and a moisture survey show whether repair, recover or replacement fits the roof.
Scope and approval. The scope, insulation requirements and asbestos status are confirmed. Replacement projects sit above most approval limits, so each is quoted for the client’s approval before work starts.
Dispatch. A vetted local roofing provider with the required licenses and insurance pulls the permit and schedules the work.
Completion. The provider documents tear-off, deck condition and the finished roof with photos, and the inspections are recorded.
Verification and invoice. The work is checked against the approved scope, the warranty is filed, and the project is invoiced in one format.

Every record sits on the location’s file in PostControl. Where open work or exterior access leaves a location unsecured, McCray can post an officer until the work is complete. See Security by McCray.

What affects the cost of a commercial roof replacement

Roof area, roof shape and the number of existing layers
Asbestos status and the removal method it requires
Amount of wet insulation and deck to replace
Energy code insulation and its effect on parapets, curbs and flashings
Drainage changes, such as tapered insulation or new drains
Rooftop equipment to disconnect, lift and reset
Access, crane lifts, staging and after-hours work
Membrane type and the warranty term required

Commercial roof replacement for retail stores, restaurants and offices

Retail stores. Tear-off above a sales floor means protecting merchandise, keeping overhead work away from entrances and scheduling crane lifts outside trading hours. Shopping center landlords often set their own roof access rules.

Restaurants. Kitchen exhaust fans are disconnected and reset with the kitchen ventilation provider, and adhesive work near air intakes is scheduled around service.

Offices. Occupied floors need notice of noise, HVAC shutdowns and interior protection.

Frequently asked questions

What is the difference between roof replacement and roof recover?

A replacement removes all existing roof covering layers down to the deck. A recover installs a new covering over the existing one, which the code allows only when the existing roof is a sound base and other conditions are met.

Can a new commercial roof go over the existing one?

Not when the roof already has two or more coverings, when the existing roof is water-soaked or deteriorated, or when it is slate, clay, cement or asbestos-cement tile. The local building official confirms the rule for each building.

Does a commercial roof replacement need a permit?

Local building departments generally require one, and the local building official confirms the rule for each building. Columbus, Ohio, for example, takes commercial reroofing applications, requires an insulation inspection before the insulation is covered and closes the permit after a final inspection.

Does the energy code apply to a roof replacement?

It can. Philadelphia applies new-construction insulation levels when above-deck insulation is replaced, with exceptions for physical constraints, and Columbus requires at least R-30 where the existing insulation or deck is exposed.

How often should a commercial roof be inspected?

The National Roofing Contractors Association recommends inspections at least twice a year, preferably in spring and fall, and after severe weather. Warranty terms, the insurer or the local authority can require more.

Does old roofing need to be tested for asbestos?

EPA’s interpretive rule states that suspect roofing should be tested. A contractor may skip testing only by following the asbestos NESHAP notification and work practice requirements as if the material contained asbestos.

Sources

Plan roof replacements across every location on one program.