How do GCs coordinate roofing with rooftop MEP, solar and equipment curbs?

Direct Answer

GCs should coordinate roofing with rooftop MEP, solar and equipment curbs before the roof is installed, rather than treating rooftop equipment as a series of penetrations to be dealt with later. The GC should coordinate structural loading, equipment locations, curb dimensions, penetrations, drainage, flashing, electrical and mechanical routing, access clearances, wind-uplift requirements, sequencing and roof-warranty requirements across the roofing, structural, MEP, solar and equipment trades.

The key principle is to establish the final rooftop layout and interface details before permanent roofing work reaches those areas. Florida Building Commission roofing detail guidance specifically identifies photovoltaic systems, equipment, roof curbs, mechanical/plumbing/electrical equipment, roof penetrations, drainage and their integration as matters that should be addressed in the roof design. :contentReference[oaicite:0]{index=0}

NRCA guidance similarly emphasizes coordination between roofing and rooftop equipment because equipment can affect drainage, structural loading, membrane and flashing performance, access and future maintenance. :contentReference[oaicite:1]{index=1}

Who This Applies To

• General contractors and construction managers
• Commercial roofing subcontractors
• Mechanical, electrical and plumbing contractors
• Solar/PV contractors
• Structural engineers
• Architects and design teams
• Commercial building owners and developers
• Florida commercial construction teams

Not for: This FAQ addresses construction coordination between roofing and rooftop systems. It does not replace structural engineering, electrical design, mechanical design, manufacturer’s installation requirements, project specifications or AHJ review.

1. Coordinate the Rooftop Layout Before Roofing Starts

The GC should create one coordinated rooftop plan showing the permanent location of all major rooftop systems before the roofing contractor begins installing the affected areas.

The plan should identify:

• HVAC units
• Equipment curbs
• Exhaust fans
• Mechanical piping
• Electrical conduits
• Plumbing penetrations
• Roof drains and scuppers
• Solar arrays
• PV racking or attachment points
• Equipment platforms
• Roof hatches
• Walkways
• Access routes
• Parapets and roof edges
• Expansion joints

The goal is to prevent a situation where the roofing contractor installs a finished roof and another trade later discovers that its equipment needs a curb, penetration or support in a location that was not coordinated.

2. Lock Equipment Curb Locations Before Membrane Installation

Equipment curbs should be coordinated before the surrounding roof assembly is completed.

The GC should verify:

• Curb dimensions
• Curb elevation
• Curb orientation
• Structural support
• Equipment dimensions
• Equipment service clearances
• Flashing requirements
• Membrane termination details
• Counterflashing requirements
• Equipment weight
• Wind-load requirements
• Drainage around the curb

NRCA guidance notes that mechanical equipment should not restrict water flow and that adequate space should be provided around equipment, penetrations and walls so roofing materials can be properly installed. It also identifies structural loading, vibration isolation, watertight equipment housings and drainage around larger mechanical units as important coordination issues. :contentReference[oaicite:2]{index=2}

3. Do Not Let MEP Trades Add Unplanned Penetrations

Every new penetration through a completed roof creates another roof-interface condition that needs to be properly detailed and flashed.

The GC should therefore establish a penetration-control process.

Before a trade creates a new roof penetration, require:

1. Location to be shown on the coordinated rooftop plan.
2. Structural implications to be reviewed where necessary.
3. Roofing details to be identified.
4. Manufacturer requirements to be checked.
5. Responsible trade to be identified.
6. Roofing contractor to coordinate the flashing.
7. Required inspection to be scheduled.
8. Final documentation to be recorded.

This is especially important after the permanent membrane has been installed. The project should avoid the practice of allowing each MEP trade to create penetrations independently and expecting the roofer to solve the resulting waterproofing conditions afterward.

4. Coordinate Roofing and HVAC Sequencing

HVAC replacement or installation can create one of the biggest coordination challenges on a commercial roof.

The GC should determine whether the project requires:

• New curbs
• Curb adapters
• Temporary equipment support
• Equipment removal before roofing
• Equipment reinstallation after roofing
• New duct penetrations
• New piping penetrations
• Electrical conduit penetrations
• Temporary weather protection

Where equipment must remain operational during roofing, the GC should establish a detailed sequence rather than allowing equipment to sit on partially completed roofing work without a defined protection and flashing plan.

Related ShieldLine guidance: How should HVAC replacement be coordinated with roof replacement?

5. Verify Curb Elevation and Roof Drainage

Rooftop equipment should not unintentionally create low points or obstruct water flow.

The GC should review:

• Roof slope
• Drain locations
• Scuppers
• Overflow drainage
• Equipment curb locations
• Equipment support locations
• Crickets and saddles
• Finished insulation elevations

Florida’s current roofing-detail development materials specifically identify roof slopes to drains, roof drains, sumps, crickets, roof-mounted equipment and integration of rooftop systems as coordinated roofing-detail considerations. :contentReference[oaicite:3]{index=3}

NRCA also recommends providing drainage crickets around large mechanical units where needed and avoiding equipment arrangements that restrict water flow. :contentReference[oaicite:4]{index=4}

6. Treat Solar as a Roof-System Coordination Issue

Solar should not be added to the roof plan after the roofing design is complete.

For a new commercial building, the GC should coordinate the PV system with the roofing and structural teams before construction.

Review:

• PV array locations
• Roof loading
• Attachment method
• Ballasted versus mechanically attached configuration
• Wind-uplift requirements
• Roof membrane compatibility
• Roof service life
• Walkways and maintenance access
• Drainage
• Electrical conduit routes
• Fire-access requirements
• Future roof replacement access
• Manufacturer warranty requirements

NRCA’s 2025 PV-ready roof guidance specifically recommends coordinating the roof system with the expected service life of the PV installation, applicable codes and standards, qualified roofing contractors and licensed electricians, while also considering warranty requirements. :contentReference[oaicite:5]{index=5}

7. Decide Who Installs and Flashes Solar Attachments

The GC should not leave responsibility for roof-to-solar interfaces ambiguous.

The project documents should establish:

• Who supplies the attachment system
• Who installs it
• Who coordinates structural attachment
• Who installs roof flashing
• Who repairs membrane damage
• Who performs waterproofing inspections
• Who coordinates manufacturer approval
• Who is responsible for the resulting warranty

NRCA’s solar guidance emphasizes collaboration between the solar and roofing industries because both systems must perform reliably over their intended service lives. :contentReference[oaicite:6]{index=6}

8. Protect the Roof Warranty When Other Trades Work on It

The GC should identify which trades are authorized to modify or penetrate the roof and what procedures they must follow.

For example, an electrical contractor should not independently drill through a roof membrane simply because a conduit needs to reach a rooftop panel.

Instead:

1. MEP identifies the required penetration.
2. GC coordinates its location.
3. Roofing contractor confirms the appropriate roof detail.
4. Manufacturer requirements are checked.
5. The penetration is installed using the approved method.
6. Roofing contractor completes the flashing/waterproofing interface.
7. The work is inspected.
8. Documentation is retained.

This process reduces the risk that another trade unintentionally compromises the roof assembly or creates a warranty issue.

See also: Does a commercial roof warranty cover damage caused by other trades on the roof?

9. Coordinate Structural Loading Before Equipment Arrives

Roof-mounted equipment is not only a roofing issue. The structural team needs to account for concentrated loads, equipment weight, support locations and applicable wind forces.

The GC should coordinate:

• Equipment weight
• Operating weight
• Support locations
• Equipment vibration
• Maintenance loads
• Solar array loads
• Wind loads
• Attachment forces
• Roof-deck capacity
• Equipment replacement loads

NRCA guidance specifically notes that structural design should account for concentrated mechanical-equipment loads and that vibration should be isolated from the roof membrane and flashing. :contentReference[oaicite:7]{index=7}

10. Coordinate Wind-Uplift Requirements

Florida projects require particular attention to wind performance. A rooftop equipment or solar installation can interact with the roof assembly, edge conditions and attachment systems.

The GC should verify the applicable design requirements for:

• Roof assembly
• Equipment curbs
• Equipment supports
• Solar attachment systems
• Perimeter conditions
• Equipment screens
• Roof-mounted accessories

Florida’s code-development and product-approval resources show that roofing components and assemblies can have specific wind-performance limitations and approval conditions. :contentReference[oaicite:8]{index=8}

Do not assume that an approved roofing assembly automatically approves every rooftop attachment or equipment configuration placed on it.

11. Plan the Sequence Around the Roof Warranty

A coordinated project will determine which work occurs before, during and after the roofing installation.

Work Item	Preferred Coordination Point
Structural curbs	Before affected roof areas are completed
Large equipment	Coordinate delivery and placement before final roof completion
MEP penetrations	Locate before membrane installation
Roof drains	Coordinate with insulation and roof slope
Solar layout	Coordinate during design/preconstruction
PV attachments	Coordinate structural and waterproofing details before installation
Equipment replacement	Coordinate with roofing and warranty requirements
Final equipment installation	Inspect roof interfaces before closeout

12. Use a Rooftop Coordination Drawing

A GC can reduce conflicts by maintaining one coordinated rooftop drawing rather than relying on separate HVAC, electrical, plumbing, solar and roofing drawings.

The drawing should show:

• Roof areas
• Roof slopes
• Drains
• Scuppers
• Curbs
• Equipment
• Solar arrays
• Penetrations
• Walk pads
• Access routes
• Parapets
• Expansion joints
• Maintenance clearances

The GC should use this drawing during coordination meetings and update it when equipment locations or penetrations change.

13. Control Rooftop Access After Roofing Is Complete

Even a properly installed roof can be damaged by subsequent MEP or solar work.

Establish rules for:

• Roof access points
• Material staging
• Equipment movement
• Temporary protection
• Walk pads
• Tools and fasteners
• Welding or hot work
• Penetration work
• Roof inspections after trade work

Every trade should understand that completing its own scope does not eliminate its responsibility to protect the roof while working on it.

14. Inspect the Roof After MEP and Solar Work

The GC should perform a roof-interface inspection after major rooftop trades complete their work and before final closeout.

Look for:

• Membrane punctures
• Damaged flashing
• Loose counterflashing
• Unsealed penetrations
• Missing sealants
• Damaged walk pads
• Improperly supported conduit
• Unapproved attachments
• Blocked drains
• Debris
• Damage from equipment placement

Document the condition with photographs and assign corrective work before the final manufacturer warranty inspection.

15. Build Rooftop Coordination Into the Closeout Package

The GC should retain documentation showing how roofing interfaces with rooftop equipment were constructed.

Useful records include:

• Approved roof plans
• MEP coordination drawings
• Solar/PV drawings
• Structural calculations where applicable
• Equipment curb details
• Penetration details
• Manufacturer approvals
• Roofing inspection reports
• Photographs
• Warranty documentation
• Equipment replacement records
• Final as-built information

This becomes particularly valuable when the owner later replaces HVAC equipment, modifies solar equipment or needs to investigate a leak.

16. GC Rooftop MEP, Solar & Curb Coordination Checklist

• ☐ Rooftop equipment layout coordinated before roofing
• ☐ Structural loading reviewed
• ☐ Equipment curb dimensions confirmed
• ☐ Curb elevations coordinated with roof assembly
• ☐ Roof drainage reviewed around equipment
• ☐ MEP penetrations identified before membrane installation
• ☐ Solar array locations coordinated
• ☐ PV attachment method reviewed
• ☐ Wind-uplift requirements verified
• ☐ Manufacturer compatibility confirmed
• ☐ Warranty responsibilities assigned
• ☐ Other-trade roof access controlled
• ☐ Temporary protection provided during rooftop work
• ☐ Roof inspected after MEP/solar installation
• ☐ All deficiencies corrected
• ☐ Rooftop coordination records included in closeout

Related Questions

• How should HVAC replacement be coordinated with roof replacement?
• Which should come first, the new roof or the new rooftop units?
• Who inspects rooftop equipment reinstallation for watertightness?
• Does adding rooftop equipment void an existing commercial roof warranty?
• Does a commercial roof warranty cover damage caused by other trades on the roof?
• What crane-pick considerations apply to rooftop equipment replacement?
• What is a curb adapter and when is one used?

Sources

• Florida Building Commission — Roofing Details and Rooftop System Integration
• NRCA — Mechanical Curbs & Penetrations
• NRCA/SMACNA/ARI — Guidelines for Roof-Mounted Outdoor and Air Conditioner Installations
• NRCA — PV-Ready Roofs
• NRCA — Roof-Mounted Solar Photovoltaic Arrays
• Florida Building Commission — Florida Building Code Resources

Last Reviewed

September 25, 2026

Related Resources

• HVAC and Roof Replacement Coordination
• New Roof vs. Rooftop Units
• Rooftop Equipment Reinstallation and Watertightness
• Roof Damage Caused by Other Trades
• Roofing Closeout Documents for GCs

Need help coordinating roofing with rooftop MEP, solar or equipment? Request Commercial Roofing & Rooftop Equipment Coordination Support from ShieldLine Roofing.

Commercial Roofing Services in Florida