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Commercial Roof Systems We shape our buildings; thereafter they shape us. -Winston Churchill

Commercial Roof Systems We shape our buildings; thereafter they shape us. -Winston Churchill

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Page 1: Commercial Roof Systems We shape our buildings; thereafter they shape us. -Winston Churchill

Commercial Roof Systems

We shape our buildings; thereafter they shape us.

-Winston Churchill

Page 2: Commercial Roof Systems We shape our buildings; thereafter they shape us. -Winston Churchill

Commercial Roof Systems

• Commercial Roof Shapes • Pitched Roof Systems• Roofing Materials for Pitched Roofs• Low-Slope Roof Systems• Roofing Material for Low-Slope Roofs

Page 3: Commercial Roof Systems We shape our buildings; thereafter they shape us. -Winston Churchill

Commercial Roof Shapes

Shed Gable Hip Gable with Dormer

Low-slope Gable & Valley Hip & ValleyGambrel

Roofs for small commercial buildings can be similar to residential pitched roof shapes.

Low-slope roofs (not completely flat) are common in large commercial construction.

Page 4: Commercial Roof Systems We shape our buildings; thereafter they shape us. -Winston Churchill

Typical Pitched Roof

Roof Covering

Underlayment

Roof Deck

Roof Framing

Page 5: Commercial Roof Systems We shape our buildings; thereafter they shape us. -Winston Churchill

Roof Coverings for Pitched Roofs

Standing Metal Seam Clay/Cement Tiles Asphalt Shingles

Wood/Cedar Slate

Can be similar to residential construction

Courtesy US Fish & Wildlife

Page 6: Commercial Roof Systems We shape our buildings; thereafter they shape us. -Winston Churchill

Pitched Roof Framing(Low Rise Buildings)

– Wood trusses or rafters– Light gauge steel trusses– Structural steel trusses– Open web steel joists (lower slopes)

Courtesy Isle of Palms Rec Dept.

Light gauge steel trusses on CMU load bearing wall

Open web steel joists on tilt-up concrete walls

Courtesy Greg Thiel

Page 7: Commercial Roof Systems We shape our buildings; thereafter they shape us. -Winston Churchill

Low-Slope Roofs

• Sometimes incorrectly called “flat” roofs

• Provide small slope to provide roof drainage and to prevent ponding

©iStockphoto.com

Page 8: Commercial Roof Systems We shape our buildings; thereafter they shape us. -Winston Churchill

Typical Low-Slope Roof

Surfacing

Insulation

Roof Framing

Weatherproofing

Roof Decking

Reinforcing

Page 9: Commercial Roof Systems We shape our buildings; thereafter they shape us. -Winston Churchill

Low-Slope Roof Materials

• Built-up Roof (BUR) membranes– “Tar and Gravel”– Alternating layers of asphalt and reinforcing

fabric– Aggregate surfacing

Photograph provided with permission from the National Roofing Contractors Association (NRCA)

Page 10: Commercial Roof Systems We shape our buildings; thereafter they shape us. -Winston Churchill

Low-Slope Roof Materials

Single Ply membranes – Often referred to by chemical acronyms

EPDM = ethylene propylene diene monomer

– Fully adhered (glued), mechanically attached (screwed), or held down by ballast (e.g., gravel)

Fully adhered EPDM roof system

Ballasted EPDM roof system

Photograph provided with permission from the National Roofing Contractors Association (NRCA)

EPDM

Photograph provided with permission from the National Roofing Contractors Association (NRCA)

wikimedia

Page 11: Commercial Roof Systems We shape our buildings; thereafter they shape us. -Winston Churchill

Low-Slope Roof Materials

Spray Polyurethane Foam (SPF) system

• Two component system– Rigid closed cell spray foam insulation– Protective coating

Photograph provided with permission from the National Roofing Contractors Association (NRCA)

Page 12: Commercial Roof Systems We shape our buildings; thereafter they shape us. -Winston Churchill

Low-Slope Roof Framing– Wood Joists – Light Gauge Steel Joists

– Open Web Steel Joists

– Structural Steel

– Structural Concrete Slab

Open web steel joist roof framing with metal decking

Couresty constructionphotographs.com

Page 13: Commercial Roof Systems We shape our buildings; thereafter they shape us. -Winston Churchill

Commercial Roof Systems

• Commercial Roof Shapes • Pitched Roof Systems• Roofing Materials for Pitched Roofs• Low-Slope Roof Systems• Roofing Material for Low-Slope Roofs

Page 14: Commercial Roof Systems We shape our buildings; thereafter they shape us. -Winston Churchill

Image Resources

• National Roofing Contractors Association (NRCA) (www.nrca.net)

• www.constructionphotographs.com• www.wikimedia.com• U. S. Fish and Wildlife Service