Commercial Roof Types Flashcards
What are the common components of a commercial roof?
- Roof accessories
- Single ply membrane
- Roof deck
- Insulation
- Fasteners
What are the characteristics and benefits of Metal Decks, Wood Decks, and Lightweight Insulating Concrete Decks (LWIC)?
- Metal Decks: Corrugated panels, various thicknesses & spans, cost-effective, good wind/fire/seismic resistance
- Wood Decks: Made of plywood or OSB, common in western U.S., excellent seismic resistance, fair to poor fire/wind/foot traffic resistance
- LWIC: Non-structural, low-density, good fire/wind/foot traffic resistance, often contain EPS insulation
What are the characteristics and benefits of Structural Concrete Decks and Poured Gypsum Decks?
- Structural Concrete: Integral to structure, designed for heavy loads, excellent foot traffic/fire/wind resistance, expensive
- Poured Gypsum: Lightweight, minimal expansion/contraction, reinforced with steel mesh, popular during WWII, inexpensive
What are the characteristics and benefits of Tectum Decks, Insulation Boards, and Cover Boards?
- Tectum: Composite strand board, sound-absorbing, issues with water damage, needs special fasteners
- Insulation Boards: ISO-Polyisocyanurate, increase R-value, improve smoothness of top membrane
- Cover Boards: Perlite, serve as separators for re-cover jobs, Class-A fire rating, puncture resistance
What are the three types of Single-Ply Systems and their benefits?
- EPDM: Long history, installs quickly, economical, good heat resistance
- PVC: Good on punctures, high flexibility, strong seams, highly reflective, chemical-resistant
- TPO: Economical, over 50% market share, flexible, fungal- and mold-resistant, high reflectivity, Energy Star-rated
What are the cons of EPDM, PVC, and TPO?
- EPDM: Poor seam integrity, human error, low strength, dark colors less energy-efficient, low puncture resistance, not chemical- or petroleum-resistant, can’t use induction welding
- PVC: Plasticizers migrate, becomes brittle, mold growth, more expensive
- TPO: New technology, changing formulations, less flexibility, reduced chemical/grease resistance
Why is TPO considered the roofing of choice?
- TPO use has grown by over 10% since 2013
- Low installation cost
- Popularity of reflective membranes
- Energy-efficient roofing systems
- Contains no asphalt
What are the six TPO attachment methods?
- Mechanically-Attached Smooth with Drill-Tec Fasteners
- Fully-Adhered Smooth
- Fully-Adhered Fleece with WB181 Wet Lay-in
- Adhered Fleece with Low-Rise Foam
- Fully-Adhered Fleece with GAF 2-Part Roofing Adhesive
- GAF RhinoBond System
What are TPO accessories, and why are they important?
- Identifies numerous accessories for commercial roofs
- Understanding accessories and their application is integral to roofing
- Factory-made accessories provide consistent detail and save on labor compared to field-fabricated accessories
What is seam strength, and why is it important for roofing?
- Seam: Where two sheets of membrane connect and are fused together
- Seam strength: Amount of force needed to pull the seam apart
- Strong seams are dependent on the quality of the weld
Match the description with the appropriate TPO Accessory: “Structural foundation for EverGuard pourable sealant”
Pourable sealer pocket
Match the description with the appropriate TPO Accessory: “TPO can be heat welded to this for a strong, secure installation”
Scupper
Match the description with the appropriate TPO Accessory: “Flange for direct hot-air welding of TPO or PVC roof membranes”
Coated speedtite drain
Match the description with the appropriate TPO Accessory: “For use in flashing outside corners of base and curb flashings”
Fluted corner
What are the two systems in GAF’s asphalt roofing business?
- GAFGLAS Built-Up Roofing System
- RUBEROID Modified Bitumen Roofing System
What are the components and application methods of the GAFGLAS Built-Up Roofing System?
- Components: Base sheets, ply sheets, cap sheets
- Application Method: Hot asphalt
What are the components and application methods of the RUBEROID Modified Bitumen Roofing System?
- APP (Atactic Polypropylene): Smooth and granule surfaced
- SBS (Styrene Butadiene Styrene): Smooth, granule, and coated surfaced
- Application Methods: Torch (APP), Heat Weld (SBS), Hot asphalt, Cold adhesive, Self-adhered
What are the characteristics of Modified Bitumen Roofing Systems?
- Heavier sheets, reduce layers in roofing system
- Combined with built-up base and ply sheets or modified smooth surface base and ply sheets
- Once popular, now less due to cost, environmental concerns, and regulations
- Push towards single-ply roofing options
What are the characteristics of Built-Up Roofing (BUR)?
- Multiple layers installed with asphalt for waterproofing
- Base sheets are heavier than ply sheets, can be used on deck or insulation
- Ply sheets installed next, then surfacing (cap sheet, gravel in hot asphalt, or coating)
- Protects roof from sun’s rays
Match the following descriptions to either Built-Up Roofing (BUR) or Modified Bitumen:
- Styrene Butadiene Styrene (SBS), smooth granule and coated surface
- Application method cold adhesive
- Application method hot asphalt only
- Comprised of base, ply, and cap sheets
- Application method torch APP and/or Heat Weld SBS
- Atactic Polypropylene (APP), smooth and granule surfaced
- Modified Bitumen: Styrene Butadiene Styrene (SBS), smooth granule and coated surface
- Modified Bitumen: Application method cold adhesive
- Built-Up Roofing: Application method hot asphalt only
- Built-Up Roofing: Comprised of base, ply, and cap sheets
- Modified Bitumen: Application method torch APP and/or Heat Weld SBS
- Modified Bitumen: Atactic Polypropylene (APP), smooth and granule surfaced
What are the characteristics of Asphaltic BUR Systems?
- Built up with plies between hot asphalt, typically mopped
- Seams sealed with asphalt
- Warranty: 10-20 years
- Minimum slope: 1/4 out of 12
- Pros: Extremely waterproof
- Cons: Danger of hot asphalt kettle
What are the characteristics of Asphaltic APP Systems?
- APP membrane typically torched down
- Seams sealed with torch
- Warranty: 10-20 years
- Minimum slope: 1/4 out of 12
- Pros: Very waterproof, no kettle
- Cons: Open flames require skill
What are the characteristics of Asphaltic SBS Systems?
- Can be laid over a wood deck
- Base and cap sheet with hot asphalt, typically mopped
- Seams sealed with asphalt, can be glued
- Warranty: 10-20 years
- Minimum slope: 1/4 out of 12
- Pros: Very waterproof, faster
- Cons: Danger of hot asphalt kettle
What are the characteristics of Self-Adhered SBS Systems?
- Liberty is a self-adhered alternative to a torch-applied modified system
- Base and cap sheet self-adhered
- Seams are self-adhered
- Warranty: 10-15 years
- Pros: Super easy, low skill
- Cons: Short longevity
