If you own commercial property in San Antonio, Boerne, or anywhere in the metro, your roof is almost certainly low-slope or "flat." It's also probably under-maintained. Commercial flat roofs are a different category from residential — they need a different approach, different materials, and different maintenance schedules.
Here's the honest version of what every commercial property owner should know.
The three main flat roof systems
TPO (Thermoplastic Olefin)
The current dominant system for new commercial construction. White or light-colored membrane, single-ply, mechanically fastened or fully adhered. Properties:
- Service life: 20–25 years installed correctly
- Energy efficient (white reflects significant solar load)
- Welded seams that perform well long-term
- Vulnerable to penetration damage and improper foot traffic
Modified Bitumen
The traditional asphalt-based system. Multiple plies, often with a granular cap sheet. Properties:
- Service life: 15–20 years
- Heavy and durable
- Affordable and well-understood by most crews
- Heat-absorbent (dark surface, higher AC load on building below)
EPDM (Ethylene Propylene Diene Monomer)
The classic "rubber roof." Less common in new construction, common on older buildings. Properties:
- Service life: 15–25 years
- Excellent UV and weather resistance
- Black surface (heat absorbent)
- Seams are the typical failure point
Why "flat" roofs aren't actually flat
A properly designed low-slope roof has 1/4" per foot of fall toward drains. When that fall isn't there — or has degraded over time as insulation compresses — water ponds. Ponding water leads to membrane degradation, biological growth, and eventually leaks.
If you have ponding on your roof more than 48 hours after rain, that's a problem to address.
Maintenance that actually matters
- Twice-yearly inspections. Spring and fall. Catch small issues before they become claims.
- Drain cleaning. Roof drains and scuppers clogged with debris back water onto the roof.
- Penetration inspection. HVAC curbs, plumbing vents, and skylights are the most common leak points.
- Seam inspection. The single most important check. Failed seams = leaks.
- Walkway pads where foot traffic happens. HVAC techs walking the membrane are a leading cause of damage.
The 5-year tipping point
Most commercial flat roofs have a "tipping point" around years 12–18. Up to that point, repairs make sense. After it, you're throwing money at a roof that's reached end-of-life. The economic case for replacement vs ongoing repair flips fast once the membrane is brittle.
What we do for commercial clients
We work with property managers and commercial owners across San Antonio and the surrounding metro on:
- Annual and semi-annual maintenance contracts
- Leak repairs and emergency response
- Re-roofing (full tear-off or recover where appropriate)
- Insurance claim management for storm damage on commercial buildings
- New TPO and modified bitumen installs with manufacturer warranties
If you manage a commercial property and want a real assessment of where your roof stands, reach out. We'll come walk it, document the condition, and give you a written maintenance or replacement plan.
