When choosing between torch-on and TPO roofing for Vancouver’s wet climate, both systems are considered excellent and proven solutions. Neither is strictly "better" than the other; rather, they offer different advantages depending on your building’s specific needs.

### Comparing the Two Systems

• Torch-On (Modified Bitumen):

Specifically noted for providing superior waterproofing during heavy rain and snow seasons. It offers high puncture resistance and has been a proven performer in high-rainfall, cool climates like the Lower Mainland for years.

• TPO (Thermoplastic Polyolefin):

Known for its high reflectivity, which helps lower cooling costs in the summer. It performs well in wet conditions provided the seams are heat-welded correctly.

### Performance Metrics

1. Lifespan:

TPO generally has a longer typical lifespan of 20–30 years, whereas torch-on typically lasts 15–20 years.

1. Maintenance:

Torch-on may require recoating every five to seven years to counter UV degradation. TPO relies on periodic seam inspections to ensure no gaps develop.

1. Safety and Compliance:

TPO installation is often simpler for site safety compliance because it uses heat-welding rather than the open-flame "hot work" required for torch-on, which necessitates specific WorkSafeBC permits.

Ultimately, the choice depends on your property’s exposure and energy goals. For any flat roof in Vancouver, the most critical factor for durability is ensuring the structure has positive drainage (to prevent ponding water) and a consistent professional maintenance schedule.