Metal Roofing and Solar

1. A durable integrated system
for PV installations on existing and new roofs

2. Presentation Content
Basics of metal roofing
Basics of photovoltaics (PV)
Synergy of solar and metal roofing
The most cost-compelling choice
Retrofitting opportunities

3. Look at the roof and PV system
together as a single asset.
Then assess the total cost of ownership
over the total life of the asset

4. Basics of Metal Roofing

5. Metal Roof Benefits
Sustainable
Reflective, emissive
More energy efficient
LEED® friendly
Made from recycled materials
100% recyclable
Aesthetically beautiful

6. Metal is Durable

7. 1200-1450

9. Metal Offers
Design Flexibility

13. Metal Provides
Long Service Life

14. Coatings for Steel
Galvanized Zinc
Aluminized™ Aluminum
Galvalume® Aluminum + Zinc

15. Metal is Sustainable

16. Sustainability
Strength, durability, longevity
• Resists harsh weather, wind, and fire with minimal or no
maintenance
• Impervious to UV degradation
• Galvalume® steel standing-seam roof has 40- to 60-year
service life, depending upon environmental severity
25% recycled content, 100% recyclable
• At a 93.3% recycle rate, steel is the most highly recycled
construction material available.*
Energy efficiency
• Meets ENERGY STAR requirements with high reflectance
Lower life-cycle cost than other roof types
*Source: Steel Recycling Institute, 2008

17. 35-year-old Galvalume® steel roof
New Orleans, LA

18. 28-year-old roof
Ergoldsbach, Germany
This roof, which is about to be retrofitted
with a PV array, is estimated to have a remaining
service life of 30 years or more.

19. Metal Roof Benefits
Features
• Sustainable
• Reflective, emissive
• More energy efficient
• LEED® friendly
• Made from recycled
materials
• 100% recyclable
• Aesthetically beautiful
Environmental Benefits
• Reduce landfill waste
• Reduce carbon footprint
• Accommodate solar
technologies
• Retain properties
• Reduce roof maintenance
• Provide long service life

20. Basics of Photovoltaics

21. Solar Power Systems
System types
• thin film
- amorphous silicon (a-Si)
- cadmium telluride (CdTe)
- copper indium selenide (CIS)
- copper indium/
gallium diselenide (CIGS)
- light-absorbing dyes
- dye-sensitized solar cells (DSSC)

22. Solar Power Systems
System types
mono- and poly-crystalline
Metal roofs accommodate necessary attachment
hardware.
Eligible for Federal solar-energy tax credits
Other benefits beyond solar energy

23. Issues: PV Attachment to Conventional Roof
Requires waterproofing
at solar array attachments
Requires dismantling
• Remove old
• Install new
• Reinstall PV

24. No holes!
PV Attachment to Metal Roof

25. Metal Roof with PV
No holes = no leaks
• Thin-film and crystalline systems
No costly reinstallation
Longer service life
• 24%–43% savings over installing PV over conventional roofs
Considerations for PV over conventional roofs must
include long-term roof-replacement cost

26. Thin Film Laminated PV
Thin-film amorphous silicon thickness =
less than 1 micron
Stainless steels substrate = 5 mil
Protective coating = ETFE film
Average weight = .7 lbs/sq ft

27. Thin-film PV is flexible, durable, and fits into
standing seam roofs

28. Thin-film applications are aesthetically pleasing,
casting no shadows or causing any glare.

29. Crystalline Si PV Panels

31. Popular for vast expanses of commercial, industrial,
office, and retail rooftops (±700,000,000 sf annually)

32. Top Solar States
Cumulative as of EOY 2008
0 100 200 300 400 500 600
North Carolina
Oregon
Connecticut
Hawaii
New York
Arizona
Nevada
Colorado
New Jersey
California
Source: IREC

33. Prices are coming DOWN!
Average wholesale and factory gate pricing (2009)
$0.00
$0.50
$1.00
$1.50
$2.00
$2.50
$3.00
$3.50
$4.00
Jan Feb Mar Apr May Jun Jul Aug Sep
Wholesale
Factory Gate

34. What is the service life of PV?
The warranted life = 25 years…
but the service life ≈ 30 years.

35. Penetration of Conventional Roof System

36. Options for mounting
to conventional roof types:
Option
• Penetrations
• Ballast
• Adhesion
• Aerodynamic
• Unique Collectors
Problem
• Cost
• Risk of leakage
• Warranty violations
• Limited to new
construction
• Added to dead load
• Limited to new or reroof
• Limited to thin-film
alternatives
• Cost
• Cost

38. More than 10,000 points of attachment

41. Conventional Roof Type
Racking components .65
Anchorage/waterproofing .20
System assembly (labor) .20
Mounting system cost 1.05
Total system cost 5.50
Total system cost 6.40
Mounting Cost Summary(dollars per Watt)
Standing Seam Metal Roof
Seam clamps and interface .10
System assembly (labor) .10
Mounting system cost .20
Total system cost 4.65
Total system cost 5.55
13% of SYSTEM COST
15.5% of SYSTEM COST

43. Source: www.energycodes.gov
Map of DOE Proposed Climate Zones
Adopted by ASHRAE and IECC

45. AGED BRONZE
COLORED ROOF:
T Sun = 174º F
T Shade = 118º F
ΔT Sun to Shade = 56º F
(ambient = 81º F)

46. A convective air plenum ensures even
cooler temperatures.

47. Conventional Roof Types: Service Life
Service life of PV = 30 years ±
Service life of BUR = 19.8 years
Service life of APP = 16.1 years
Service life of SBS = 17.7 years
(The service life of other commercial roof types = 12–20 years.)
Source: Carl Cash Survey, Simpson, Gumpertz & Heger, 2005

48. Conventional Roof Types: Service Life
Service life of PV = 30 years ±
Service life of BUR = 19.8 years
Service life of APP = 16.1 years
Service life of SBS = 17.7 years
(The service life of other commercial roof types = 12–20 years.)
Source: Carl Cash Survey, Simpson, Gumpertz & Heger, 2005

49. So when roof life expires…
dismantle the PV array…
tear the roof off…

50. throw it away…
reroof, and then…
reassemble the PV array.

51. SSMR: Service Life
Service life of PV = 30 years
Service life of SSMR = 50 years
No roof replacement—the roof outlives the PV system!

52. SSMR: Service Life
Service life of PV = 30 years
Service life of SSMR = 50 years
No roof replacement—the roof outlives the PV system!

53. Coated Steel SSMR
Initial cost of roof $ 7
Initial cost of PV $56
Initial cost Subtotal $63
Total 30-year cost $63
(20-year roof life surplus)
Economic Impact of Roof Replacement
(assuming new construction)
15-Year TPO Single-Ply
Initial cost of roof $ 4
Initial cost of PV $64
Initial cost Subtotal $68
Yr 15 PV removal $ 4
Yr 15 Roof Recover $ 3
Yr 15 PV re-assy $ 9
Total 30-year cost $84
(0 roof life)

54. Coated Steel SSMR
Initial cost of roof $ 7
Initial cost of PV $56
Initial cost Subtotal $63
Total 30-year cost $63
(20-year roof life surplus)
Economic Impact of Roof Replacement
(assuming new construction)
15-Year TPO Single-Ply
Initial cost of roof $ 4
Initial cost of PV $64
Initial cost Subtotal $68
Yr 15 PV removal $ 4
Yr 15 Roof Recover $ 3
Yr 15 PV re-assy $ 9
Total 30-year cost $84
(0 roof life)

56. Method: Direct Mount—seam clamp and interface
Mounting system cost: $0.087/watt

57. Look at the roof and PV system
together as a single asset.
Then assess the total cost of ownership
over the total life of the asset

58. Retrofit Solutions
for Existing Buildings

59. Solutions for any reason or purpose

60. Solutions for any reason or purpose

62. Before
After

63. Reroofing Solutions
Metal over existing flat roofs
• Replace petroleum-based roofing products
• Add slope to a flat or nearly flat roof
• Enhance aesthetics, curb appeal

64. Retrofit
Economical for new construction
Flat Roof Applications
After
Before During
Before

65. Reroofing Solutions
Metal over existing flat roofs
• Replace petroleum-based roofing products
• Add slope to a flat or nearly flat roof
• Enhance aesthetics, curb appeal
Metal over existing sloped roofs
• Replace petroleum-based roofing products
• Upgrade wind-uplift and energy requirements
• Restore aged metal roofs

66. Sloped Roof Solutions

67. Reroofing Solutions
Metal over existing flat roofs
• Replace petroleum-based roofing products
• Add slope to a flat or nearly flat roof
• Enhance aesthetics, curb appeal
Metal over existing sloped roofs
• Replace petroleum-based roofing products
• Upgrade wind-uplift and energy requirements
• Restore aged metal roofs
Metal can alter roof geometry to improve drainage
issues and reorient slope for optimal solar gain

68. Problematic Roofs
During Near Complete
During After

69. Energy-Saving Opportunities
Significant savings, minimal investment
Energy savings from
• adding insulation

70. Insulated Applications
Existing roof
and purlins
New metal roof
New subpurlins
New insulation

71. Energy-Saving Opportunities
Significant savings, minimal investment
Energy savings from
• adding insulation
• radiant barrier
installation
• convective ventilation

72. Natural Convective Ventilation (ASV)
New metal roof
Existing roof
Hot air out
Ambient air in
Air heats up
and moves upward
by convection

73. Energy-Saving Opportunities
Significant savings, minimal investment
Energy savings from
• adding insulation
• radiant barrier
installation
• convective ventilation
• renewable solar
- thermal heat recovery
- solar water heating

74. Solar Thermal Heat Recovery
Ambient air inHeated air distributed
to HVAC system with
solar powered fan
Air heats up
and moves upward
by convection
New metal roof
Existing roof
Winter –closed ridge

75. Solar Thermal Water Heating
New metal roof
Optional insulation
Vented eave
Circulated fluid
in flexible tubing heats up
Reflective radiant barrier
and insulation

76. Retrofit Makes $ense
Energy Saving Solutions

77. Summary
The ideal platform for PV installation
A sustainable product
A strong synergy between PV and metal roofing
Significant cost savings possible over life of metal roof
Retrofit opportunities allow for PV benefits on existing
buildings