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During a commercial re-roof, rooftop equipment, solar installations, curbs, vents, pipes, conduits, and other roof penetrations must be carefully coordinated so the new roof system remains watertight, serviceable, code-compliant, and compatible with the equipment that remains in place.
The first step is to inventory everything on the roof before work begins. The roofing contractor, building owner, facility team, equipment contractors, solar contractor, and other affected trades should determine which equipment must be temporarily removed, raised, protected, disconnected, or worked around. Penetrations should be inspected because NRCA identifies roof penetrations as common locations for moisture infiltration and deterioration during roof replacement. :chatgpt-content-reference{index=”0″}
Solar requires additional planning. The roof’s expected service life should be considered against the solar installation’s expected service life, and qualified roofing and electrical professionals should coordinate the work. NRCA’s guidance on PV-ready roofs specifically emphasizes matching roof-system service life with the PV installation and coordinating qualified roofing contractors and licensed electricians. :chatgpt-content-reference{index=”1″}
Who This Applies To
- Commercial property owners
- Facility and property managers
- General contractors
- Developers and owner’s representatives
- Solar project owners and contractors
- Building engineers and facility teams
- Commercial roofing contractors
- Owners planning a commercial roof replacement or re-roof
Not for: This is general commercial roofing guidance. Equipment disconnection, electrical work, structural modifications, solar removal, engineering, permits, and manufacturer requirements should be handled by appropriately qualified professionals.
1. Create a Rooftop Equipment and Penetration Inventory
Before roofing work starts, create a complete inventory of everything that interacts with the roof.
This may include:
- HVAC units
- RTUs and packaged units
- Exhaust fans
- Vents and stacks
- Pipe penetrations
- Electrical conduits
- Communication lines
- Roof curbs
- Skylights
- Plumbing penetrations
- Solar panels and racking
- Satellite or communication equipment
- Walkway systems
- Fall-protection equipment
- Roof hatches and access systems
Document the location and condition of each item before demolition begins.
2. Decide Which Equipment Must Be Removed or Temporarily Supported
Not every rooftop unit needs to be removed during every re-roof. The decision depends on the roof system, equipment configuration, curb height, available working space, manufacturer requirements, and the scope of the project.
Possible approaches include:
- Temporarily removing equipment
- Temporarily disconnecting equipment
- Raising equipment where appropriate
- Working around equipment
- Using temporary protection while roofing occurs
- Replacing equipment as part of a coordinated project
Do not allow a roofing crew to disconnect electrical, HVAC, solar, or other specialized systems without coordination with the responsible trade.
3. Inspect Existing Curbs and Penetrations Before the New Roof Is Installed
Existing curbs and penetrations should be inspected while the old roof system is being removed or exposed.
Look for:
- Rot or deterioration
- Corrosion
- Loose framing
- Damaged curbs
- Improper flashing
- Water damage
- Inadequate curb height
- Movement between components
- Previous repairs
NRCA’s replacement guidance specifically recommends inspecting areas around rooftop penetrations after removal of an existing roof system because penetrations can conceal moisture infiltration and deterioration. It also recommends repairing or replacing penetration materials that do not have a service life compatible with the new roof system. :chatgpt-content-reference{index=”2″}
4. Coordinate HVAC Work With the Roofing Schedule
HVAC replacement and roof replacement frequently overlap. If new rooftop equipment is being installed during the same project, the sequencing should be established before roofing begins.
The team should determine:
- Whether existing units will remain
- Whether units will be replaced
- Whether curbs need modification
- Who is responsible for temporary removal
- Who protects the roof during equipment work
- When equipment can be returned to service
- Who is responsible for final flashing and watertightness
Ideally, the roofing contractor and HVAC contractor should coordinate the work rather than having equipment trades independently disturb newly installed roofing.
5. Treat Roof Penetrations as Critical Waterproofing Locations
Every penetration creates a potential pathway for water intrusion if it is not properly integrated with the new roof system.
Pay particular attention to:
- Pipe penetrations
- Electrical conduits
- Equipment curbs
- Exhaust fans
- Vents
- Roof hatches
- Skylights
- Mechanical supports
- Solar attachments
The new membrane and flashing details should be compatible with the existing and new components. GAF’s commercial guidance also emphasizes careful treatment of low-slope roof penetrations because gaps around penetrations can create performance problems within the roof assembly. :chatgpt-content-reference{index=”3″}
6. Coordinate Solar Before Roofing Starts
If solar panels are already installed, determine whether the solar array must be removed and reinstalled or whether the roof can be replaced around the existing system.
Consider:
- Solar panel removal
- Racking removal
- Electrical disconnects
- Conduit routing
- Attachment points
- Roof penetrations
- Warranty requirements
- Structural loading
- Reinstallation sequencing
- Future roof access
NRCA’s PV-ready roof guidance recommends considering the service life of the roof against the service life of the PV system and involving qualified roofing contractors and licensed electricians in the installation. :chatgpt-content-reference{index=”4″}
7. Decide Whether Solar Should Be Reinstalled on the New Roof
A roof replacement can be an opportunity to reconsider the timing of solar installation.
If the existing roof is being replaced shortly before a solar installation is planned, coordinating the projects may reduce the risk of installing a long-lived solar system over a roof that will soon require replacement.
Conversely, if an existing solar array is relatively new, the owner may need to evaluate the cost and logistics of removal and reinstallation against the remaining roof life.
The decision should consider the expected service life of both systems rather than looking only at the immediate roofing cost.
8. Protect Existing Equipment During Demolition
During tear-off, existing equipment must be protected from roofing debris, dust, water, vibration, and accidental damage.
Protection may include:
- Temporary covers
- Protected equipment shutdowns
- Temporary weather protection
- Controlled debris removal
- Restricted access around sensitive equipment
- Coordination with building operations
This is particularly important for facilities where rooftop equipment supports critical building operations.
9. Protect Hidden Electrical and Communication Components
Reroofing crews should know where concealed conduits, wiring, and other services are located before demolition.
NRCA has specifically highlighted the risk of concealed electrical wiring and conduit near roof assemblies and notes that accidental damage can occur during reroofing. :chatgpt-content-reference{index=”5″}
Before tear-off, identify known electrical and communication pathways and coordinate with the appropriate trade when their location is uncertain.
10. Rebuild Flashing and Penetration Details With the New Roof
After the new roof membrane is installed, each penetration must receive the appropriate flashing and waterproofing treatment for the selected roof system.
The work should address:
- Base flashing
- Counterflashing
- Penetration boots
- Equipment curbs
- Termination details
- Sealants where specified
- Membrane transitions
- Drain and scupper interfaces
Do not assume that an old flashing detail can simply be reused because the equipment itself remains in place.
11. Coordinate Other Trades Before They Return to the Roof
One of the biggest risks after a new roof is installed is damage caused by other trades.
Before HVAC, electrical, solar, telecommunications, or other contractors return to the roof, establish:
- Approved access routes
- Protection requirements
- Equipment staging areas
- Walkway requirements
- Penetration rules
- Repair responsibility
- Roof-access documentation
This reduces the chance that a newly installed membrane will be punctured or damaged after the roofing contractor has completed its work.
12. Verify Final Watertightness and Closeout
At the end of the project, inspect the completed roof around all equipment and penetrations.
Verify:
- Flashing is complete
- Penetrations are properly sealed
- Equipment curbs are properly integrated
- Solar attachments are properly addressed
- Drainage remains unobstructed
- No visible membrane damage exists
- Other trades have not damaged the roof
NRCA’s reroofing guidance emphasizes inspection and repair of penetration components as part of complete roof-system replacement. :chatgpt-content-reference{index=”6″}
13. Coordinate Manufacturer Warranty Requirements
If the new roof is covered by a manufacturer warranty, determine what inspections, installation requirements, approved details, and documentation are required before closeout.
Equipment and solar work should not inadvertently compromise the roof warranty.
Keep:
- Roofing specifications
- Equipment coordination records
- Solar documentation
- Penetration details
- Photographs
- Inspection reports
- Warranty documents
- Closeout drawings
- Repair records
14. What Happens When Existing Equipment Cannot Be Moved?
Sometimes equipment is too large, too critical, or too difficult to remove economically. In those situations, the roofing design must account for the existing equipment and provide workable installation and flashing details.
That may require specialized sequencing, temporary support, localized demolition, equipment protection, or coordination between the roofing and mechanical teams.
The important point is that the roof should not be left with inaccessible or poorly detailed areas simply because equipment prevented normal installation access.
15. Plan for Future Maintenance Access
The completed roof should remain accessible for future inspection and maintenance of HVAC units, solar equipment, and other rooftop systems.
Consider:
- Permanent walkways
- Safe access routes
- Equipment service clearances
- Roof hatches
- Fall-protection systems
- Solar maintenance access
- Drain access
A new roof should not create an environment where future equipment servicing requires unnecessary traffic across vulnerable membrane areas.
Bottom Line
During a commercial re-roof, rooftop equipment, solar systems, and penetrations should be treated as part of the overall roofing coordination plan—not as separate items to deal with after the membrane is installed.
Inventory the equipment first, determine what must be removed or protected, inspect existing curbs and penetrations, coordinate HVAC and solar work, protect concealed utilities, install compatible flashing details, control access by other trades, and complete a detailed closeout inspection.
NRCA’s reroofing guidance identifies roof penetrations, drainage, perimeter conditions and concealed components as important considerations during replacement. Its PV guidance also emphasizes coordination between roofing and electrical professionals and matching roof-system service life with photovoltaic installations. :chatgpt-content-reference{index=”7″}
Related Questions
- How should HVAC replacement be coordinated with roof replacement?
- Which should come first: the new roof or the new rooftop units?
- Does adding rooftop equipment void an existing warranty?
- Why should a commercial roof be assessed before installing solar?
- Who inspects rooftop equipment reinstallation for watertightness?
Sources
- National Roofing Contractors Association — Replacement Guidelines
- National Roofing Contractors Association — PV-ready Roofs
- National Roofing Contractors Association — Reroofing and concealed electrical components
- GAF — Dealing With Low-Slope Roof Penetrations
Last reviewed: October 2026
Related Resources
What Does a GC Need to Know About Manufacturer Warranty Inspections on a New Commercial Roof?
Need Commercial Roofing Help?
ShieldLine Roofing can help commercial property owners coordinate rooftop equipment, penetrations, solar systems, flashing and other roof interfaces during commercial re-roofing projects.
Disclaimer: This information is provided for general educational purposes and is not engineering, electrical, structural, roofing, legal, insurance, or code-compliance advice. Project-specific requirements should be confirmed with the roofing contractor, design professional, equipment contractors, solar contractor, manufacturer, and applicable authority having jurisdiction.
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