Commercial Roofing FAQ

TPO (Thermoplastic Polyolefin) and EPDM (Ethylene Propylene Diene Monomer) are the two dominant single-ply membrane systems for flat and low-slope commercial roofing. Here's how they compare:

TPO: - White or light gray membrane — high UV reflectance, reduces cooling loads - Heat-welded seams — the strongest seam bond available in single-ply roofing - Excellent UV resistance - Better puncture resistance than EPDM in most configurations - Lifespan: 15–25 years with proper installation - Cost: $5–$10/sq ft installed

EPDM: - Black rubber — absorbs heat (increases cooling load; some manufacturers offer white-coated products) - Adhesive or tape seams — historically the weak point; modern adhesives have improved significantly - Superior cold-weather flexibility — doesn't become brittle in subzero temperatures - Easier field repairs — contact cement and patches are straightforward - Lifespan: 15–25 years with proper installation - Cost: $4–$8/sq ft installed

The honest verdict: TPO is the market-preferred choice for most new commercial installations due to its reflective surface and heat-welded seams. EPDM remains preferred in cold climates and for some building types. In retrofit situations, matching the existing system is usually preferable to changing materials.

Commercial roofing repair costs vary significantly based on the system type, damage extent, and scope. Here's a realistic range:

Spot repair — single membrane puncture or seam failure (<25 sq ft): $400–$1,500 Medium section repair (25–200 sq ft): $1,500–$5,000 Large section replacement (>200 sq ft): $4,000–$15,000 Penetration flashing replacement (HVAC curb, drain, pipe): $400–$1,200 per unit Seam re-welding (TPO) or re-adhesion (EPDM) — per linear foot: $15–$45 Drain repair or replacement: $300–$900 each Infrared moisture scan — per 10,000 sq ft of roof: $500–$1,500

What drives cost up: - Multiple wet insulation areas requiring replacement (wet insulation must be removed before coating or repair) - Restricted access — high parapet walls, active HVAC equipment, occupied tenant spaces below - Emergency or after-hours response - System mismatch — replacing EPDM with TPO sections because original material is unavailable

Get a written scope of work, not just a price. Commercial repair scopes should specify material type, seam treatment, flashing approach, and warranty.

Restoration is appropriate when the roof structure is sound but the surface is aging. Replacement is necessary when the underlying structure is compromised. Here's the decision framework:

Restoration is the right call when: - Wet insulation (from infrared or moisture scan) is less than 25% of total roof area - The membrane is intact — no large tears, significant punctures, or major open seams - The drain and drainage system are functional - The roof has been maintained with no major ongoing leak issues

Replacement is necessary when: - Wet insulation exceeds 25–30% of total area - The membrane is beyond repair — cracking throughout, seams consistently failing - Structural deck damage is present - The roof is on its second or third restoration cycle

The cost comparison (typical 20,000 sq ft commercial roof): - Restoration: $3–$7/sq ft = $60,000–$140,000 - Full replacement: $12–$25/sq ft = $240,000–$500,000

That's a potential savings of $180,000–$360,000 if the roof qualifies for restoration. The eligibility inspection (free) is the only way to know which applies to your building.

One rule: Restoration adds 10–20 years. It doesn't add forever. A building owner who restores today should budget for full replacement in 12–18 years.

Commercial claims follow the same general process but with higher stakes and more documentation requirements:

Coverage differences: Commercial policies often have higher deductibles (sometimes 2–5% of building value for wind/hail), more specific exclusion language, and may require maintenance records to substantiate coverage.

Documentation requirements: Commercial adjusters expect a more detailed scope — infrared moisture scan reports, membrane specification sheets, penetration count by type, drainage assessment, and square footage broken down by section. Property management documentation standards are higher.

Business interruption: Commercial policies may include business interruption coverage for roof-related losses — tenant relocation costs, lost rent during repairs, equipment damage from water infiltration. This is worth reviewing when filing.

Scope disputes: Commercial claims for large roofing systems often involve significant scope disputes. The difference between "repair this section" and "replace this section" on a 30,000 sq ft industrial roof is hundreds of thousands of dollars. Professional documentation from a commercial roofing contractor is essential.

Maintenance requirements: Some commercial policies require documented regular maintenance as a condition of coverage. If your building doesn't have inspection records, now is the time to establish them.

Public adjusters: For commercial claims over $100,000, a licensed public adjuster is often worth hiring. They typically charge 10–15% of the recovery but bring expertise that often results in larger settlements.

The industry standard for commercial flat roof maintenance:

Twice per year (spring and fall): Full inspection of membrane, seams, penetrations, flashings, drains, and parapet walls. Many commercial maintenance agreements use this schedule.

After any significant weather event: Hail, sustained high winds, heavy snow load — any of these warrants a post-event inspection, even if nothing looks wrong from interior.

Before lease renewals or property transactions: A formal roof condition report protects both parties and establishes the baseline for warranty and insurance purposes.

What a proper inspection documents: - Membrane condition and percentage of surface affected by blistering, cracking, or ponding - Seam integrity — all seams checked for separation, bubbling, or adhesion failure - Penetration flashing condition — each HVAC curb, drain, pipe, and skylight inspected - Drain condition and flow rate — clogged drains are the most common cause of flat roof ponding - Parapet wall cap and interior face condition - Photos with location references for all deficiencies

Buildings that maintain documented inspection records have better insurance claim outcomes, faster permit processes, and better tenant relations when they can demonstrate proactive maintenance.

Ponding water — water that remains on the roof surface more than 48 hours after rain — is one of the most common and damaging conditions on flat commercial roofing.

Common causes: - Clogged or undersized drains — the most common cause; often a maintenance issue - Compressed or failed insulation creating low spots - Structural deflection between roof framing members - Poor original slope (minimum 1/4" per foot is required by most codes for single-ply membranes) - Settlement of the building structure creating new low areas

Why it's serious: - Standing water exerts 5+ lbs of pressure per sq ft — it concentrates load on the lowest points - Water finds any weakness in membrane, seams, or flashing and enters the building - Wet insulation loses R-value permanently and must be replaced, not dried - Algae and moss grow in ponded areas, degrading membrane adhesion - Many warranties are voided by documented ponding water in the same area

Solutions: - Clean drains first — this alone solves many ponding problems - Add scuppers or drains to chronic ponding areas - Apply tapered insulation to create positive drainage toward drains - For surface-level fixes only: fill the low point with elastomeric coating to level it (temporary)

Any persistent ponding area warrants contractor evaluation — it will eventually cause a leak, and the later you address it, the more insulation replacement will be required.

Commercial roofing system lifespans vary significantly by system type, installation quality, climate, and maintenance:

| System | Rated Lifespan | Real-World With Maintenance | |---|---|---| | TPO (standard) | 15–20 years | 12–18 years | | TPO (60 mil, quality install) | 20–25 years | 18–25 years | | EPDM (standard) | 15–20 years | 12–20 years | | EPDM (60 mil) | 20–30 years | 18–25 years | | PVC | 20–30 years | 18–25 years | | Modified Bitumen | 15–20 years | 12–20 years | | Built-Up Roofing (BUR) | 15–30 years | 15–25 years | | SPF Foam (with recoating) | Indefinite | Continuous with 10-year recoating |

Key factors that extend lifespan: - Proper installation by certified applicators - Membrane thickness — 60 mil significantly outperforms 45 mil - Drainage that prevents ponding - Semi-annual inspections with prompt small repairs - Climate — UV exposure and temperature cycling affect all systems

Buildings with documented maintenance programs consistently get more life from commercial roofing than buildings managed reactively.

Commercial roof restoration uses elastomeric coating systems applied over the existing membrane. The three main types:

Silicone: - Best ponding water resistance — silicone remains flexible and waterproof even in areas that pond - High UV resistance — doesn't chalk or degrade from UV exposure - Cannot be overcoated with most products — future recoating requires silicone again - Cost: $4–$8/sq ft installed - Best for: ponding-prone roofs, high UV climates, flat-to-no-slope applications

Acrylic: - Best reflectivity — highest SRI ratings for heat reduction - Lowest ponding water resistance — not suitable for areas that hold water - Easiest to overcoat with future applications - Cost: $3–$6/sq ft installed - Best for: roofs with positive drainage, hot climates where cooling reduction is the priority

Elastomeric (polyurethane, butyl, SBS-modified): - Good all-around performance - Better elongation than acrylic — handles movement and thermal cycling well - Intermediate ponding resistance - Cost: $4–$7/sq ft installed - Best for: mixed-use applications, regions with significant temperature cycling

The right choice depends on your roof's drainage pattern, your primary concern (cooling vs waterproofing), and the existing membrane material. A certified applicator from our contractor network can assess and recommend based on your specific building.

Rooftop HVAC is one of the most common sources of commercial roof damage — not from the equipment itself, but from how it's installed and maintained.

Most common HVAC-related roofing problems:

Curb flashing failure: The sheet metal flashing around HVAC unit curbs degrades over time. Water infiltrates between the curb and membrane, causing leaks that appear inside the building far from the actual entry point.

Condensate drain failures: HVAC condensate discharge can saturate membrane areas if not properly directed to a drain. Chronic wet spots from condensate accelerate membrane degradation.

Heavy foot traffic: HVAC techs accessing rooftop units create foot traffic that punctures lightweight membranes (especially 45 mil TPO) at concentrated points. Walk pads at equipment access routes solve this.

Ductwork penetration failure: Flexible connections between ductwork and the roofing membrane fail from UV and thermal cycling.

Vibration: Large commercial units generate vibration that loosens curb fasteners and stresses surrounding membrane.

Best practices: - Install walk pads from roof access points to all HVAC units - Inspect curb flashings every 2 years, reseal as needed - Keep condensate drains clean and directed properly - Coordinate HVAC maintenance visits with a roof inspection — have a roofer present or inspect after HVAC work

Roof warranties are often voided by improper HVAC work on the roof surface. Document all equipment access and coordinate maintenance.

A properly specified commercial roofing project carries two distinct warranties:

Manufacturer system warranty: - Covers material defects and, in some programs, installation performance - Duration: 10, 15, 20, or 25 years depending on system spec and contractor certification - Requires: installation by a manufacturer-certified contractor, specific material components (no mixing manufacturers), and minimum membrane thickness - Transferable to new building owner in most cases - Manufacturer warranties for TPO/EPDM typically require the contractor to be factory-certified

Contractor workmanship warranty: - Covers installation quality — leaks from installation errors (missed welds, improper seaming, flashing mistakes) - Duration: typically 2–5 years on commercial work; 10 years for some certified programs - Not transferable in most cases - Only as good as the contractor's financial stability — verify they're established

What to ask before signing: - What is the manufacturer warranty term, and what level of contractor certification does it require? - What is your workmanship warranty, and is it backed by a third-party guarantee if your company closes? - What maintenance does the warranty require to remain valid? - What voids this warranty?

Commercial roofing warranties are worth scrutinizing. A 20-year manufacturer warranty that requires annual inspection and documentation to remain valid is not the same as an unconditional 20-year warranty.