Roofing Decisions Are Complex

by Michael Rew, Vice President of Technical Services, CentiMark

At CentiMark, we re-roof commercial and industrial flat roofs throughout North America. We install roof systems including: Thermoplastics (TPO, PVC), EPDM (rubber), modified bitumen, coatings, metal, spray polyurethane foam and BUR (built-up roofing).

Roofing decisions include considerations of building use, climate and budget.

Roofs must withstand more attacks from nature than any other building component. These factors include: large temperature range of performance, thermal shock (large temperature swings), solar radiation (UV and heat), rain, snow, airborne pollutants, fungal attacks and wind forces.

1. Why are today’s roof systems so complicated?

Ongoing technical advances lead to using new materials and more complex roof system designs.

• New types of roof decks
• Insulation - how and where to use
• Vapor barriers - when and where
• Membranes - a variety of offerings
• Flashings

All of these are used in countless combinations that have vastly complicated the field installation process and require greater sophistication and understanding of their effects on the final roof solution.

2. What factors should I consider when making a decision about my roof?

• Local building code compliance
• Initial cost and life cycle (long term) cost
• Energy conservation opportunities
• Value and importance of building contents
• Required service life and expected performance
• Type of roof deck and its unique limitations
• Climate and environmental factors at the job location
• Maintenance required for optimal performance

3. What forces and factors act on your roof?

• Wind
• Rain, snow and ice
• Hail
• UV (ultraviolet) exposure
• External fire propagation

4. What additional factors must a roof resist?

• Foot traffic
• Chemical effluents
• Animal or vegetable oil, fats and grease
• Thrown objects - icicles, trash, bottles, cigarettes
• Dirt and contamination