Prepared by Commercial Roofing Advisors · Updated
The right flat roof system starts with the building: its existing assembly, drainage, rooftop activity, and the condition underneath the surface. Use this guide to compare eight roofing paths, then confirm which ones your roof can actually support.
Commercial Roofing Advisors installs, repairs, restores, and replaces commercial roofs. We connect inspection findings to a practical roofing scope, budget, and schedule for your property.
The comparison at a glance
Compare flat roof systems by fit and scope
Read across each row before choosing a material. A coating retains a qualifying existing roof; a replacement installs a new assembly. Metal roofing also needs a panel system and slope suited to the building. Those are different construction decisions, even when every option is intended to keep the same property dry.
Swipe or scroll across the chart to see all four columns.
| System | Where to consider it | What needs attention | What changes the scope and budget |
|---|---|---|---|
| TPO | Reflective single-ply roofing for warehouses, offices, and retail buildings. | Heat-welded seams; protection at service paths, curbs, and penetrations. | Membrane thickness, insulation, attachment, edge details, and tear-off requirements. |
| PVC | Single-ply roofs where grease or chemical exposure deserves particular attention. | Heat-welded seams; verify the specific membrane against the actual rooftop discharge. | Formulation, chemical exposure, flashing details, insulation, and attachment. |
| EPDM | Flexible rubber membrane for a range of low-slope commercial buildings. | Taped or adhesive seam details; check existing seams, flashings, and surface condition. | Sheet layout, seam work, attachment, insulation, and rooftop access. |
| Modified bitumen | Asphaltic roofs where a layered assembly fits the building and service demands. | Reinforced sheets with different installation methods; review laps and surfacing. | Number of plies, application method, protection, and removal of the existing assembly. |
| Built-up roofing (BUR) | Buildings suited to multiple asphalt-and-reinforcement plies. | Review surfacing, flashings, drainage, and the weight of the full assembly. | Ply count, surfacing, structural capacity, access, and disposal. |
| Spray polyurethane foam (SPF) | Roofs where a sprayed insulating assembly fits the substrate and project conditions. | Protective covering and ongoing maintenance are essential; inspect coating condition. | Preparation, foam thickness, protective coating, application conditions, and maintenance. |
| Metal roofing | Existing metal buildings or a designed metal roof assembly at an approved slope. | Panel seams, fasteners, penetrations, corrosion, and thermal movement. | Panel profile, minimum slope, support, insulation, and transition details. |
| Restoration coatings | An existing roof that is sound enough to retain after necessary repairs. | Verify substrate compatibility, moisture, preparation, adhesion, and specified thickness. | Wet-area removal, repairs, cleaning, coating specification, and warranty requirements. |
This is a planning comparison. The full roof assembly, manufacturer requirements, building conditions, and applicable approvals determine the specification. Compare roof service-life planning ranges separately from warranty terms.
Start with your roof
Not sure which system you have? #
Tell us the property address, the current concern, and your timing. We can inspect the roof and explain the repair, restoration, or replacement work that fits its condition.
From CRA projects
What the roof condition changes
These are actual roofs from CRA projects. They show why a system name alone cannot settle the scope. Each example identifies the stage of work and the limits of what was completed or recommended.
Columbus: targeted TPO repairs
The assessment led to temporary patching at 22 locations. It addressed identified defects while retaining the existing roof. It was a repair scope, with further roof decisions still dependent on condition and performance.
See the TPO repair project
Louisville: two systems, different defects
The TPO section and standing-seam metal roof required different findings and replacement recommendations. This is an assessment and resulting proposal; it does not represent a completed reroof.
See the mixed-roof assessment
Charleston: repair before recoating
Approximately 700 square feet of work addressed deterioration, fasteners, panel defects, and penetration details before compatible recoating. The completed scope covered the designated area.
See the metal roof repair projectChoose the complete assembly
Single-ply: compare the details
TPO and PVC use heat-welded seams; EPDM uses different seam and flashing methods. The useful comparison includes the deck, insulation, attachment, edge metal, penetrations, and warranty specification around that membrane.
Where kitchen exhaust or another rooftop discharge is present, identify the substance and check compatibility with the specific product. Membrane names alone do not establish resistance to every chemical. Compare TPO and PVC in more detail.
Layered, sprayed, and metal roofs
Modified bitumen and BUR provide layered asphaltic options, with different application and surfacing requirements. SPF combines sprayed insulation with a protective covering that needs planned inspection and maintenance.
Metal calls for a suitable panel profile, minimum slope, support, and properly detailed transitions. An existing metal roof may need localized repair, restoration, or replacement. Confirm those conditions before comparing it with a membrane-roof proposal.
Decide what can stay before pricing what comes next
A recover adds a new roofing assembly over an eligible existing roof. A restoration coating treats a compatible existing surface after preparation and repairs. A tear-off exposes the layers below for removal and reconstruction. Comparing those prices without comparing the retained materials can hide a major difference in scope.
Moisture, deck condition, drainage, previous layers, attachment, and manufacturer requirements all influence what can remain. Where wet areas are present, the scope must identify how they will be removed and repaired. A new surface does not resolve an unsuitable underlying assembly.
A coating proposal should explain preparation, defect repairs, adhesion checks, application thickness, detail reinforcement, and the warranty offered. A replacement proposal should explain insulation, attachment, flashings, drainage, and the treatment of concealed conditions. Review coatings versus replacement and the factors behind commercial roof pricing.
What to establish in a roof inspection
Bring the building address, leak history, available warranty documents, and any existing roof reports. You do not need to identify the membrane before contacting us. The inspection should establish the conditions needed to make the next roofing decision.
- Identify the assembly. Record the roof covering, attachment, accessible layers, previous repairs, and available installation information.
- Document the details. Inspect seams, flashings, penetrations, perimeter transitions, and areas affected by service traffic or rooftop equipment.
- Investigate moisture and drainage. Review water entry, ponding patterns, drains, and insulation concerns. Identify when moisture testing or core samples are needed.
- Define workable options. Explain which materials can remain and what repair, restoration, recover, or replacement would include.
- Connect the scope to operations. Establish access, phasing, interior sensitivity, timing, warranty requirements, and the assumptions behind the budget.
From inspection to roofing work
Get a clear next step for your building
CRA inspects, installs, repairs, restores, and replaces commercial roofs. Start with the property address and the issue you need resolved. We will help define the roofing scope and next steps.
Active leak or urgent roof concern? Call CRA at 817-631-7212. Tell us where water is entering and whether building operations are affected.
Questions owners ask before choosing
Which flat roof system is best for my building? #
Start with roof condition, slope, deck and insulation, drainage, exposure, rooftop use, and your project goals. Compare assemblies that meet those constraints. An inspection helps determine whether the decision is a repair, restoration, recover, or full replacement before a material is selected.
Can I compare roofing options by price per square foot? #
Use price per square foot only after checking the included scope. Tear-off, wet insulation, deck work, access, flashing, drainage corrections, and warranty terms can change the work substantially. Ask for those assumptions in writing so each price describes a comparable project.
Does a new coating replace the existing roof? #
A restoration coating relies on the roof beneath it. Its suitability depends on that assembly's condition, compatibility, preparation, and repairs. It does not replace wet insulation or a damaged deck. Confirm the eligible substrate and the complete scope before approving the work.
Keep comparing the right questions
Technical reading
Use the current product requirements and a property-specific scope when specifying an assembly. Further reading: GAF single-ply systems, GAF asphaltic systems, GAF roof recover guidance, and SPFA roofing installation and maintenance.