Roof Replacements and Upgrades

What are Roof Replacements and Upgrades?

Figure 1 – Cool roof with a highly reflective acrylic top coat that helps reduce carbon emissions and lowers internal building temperatures. (Source: Design Build Network)

Roof replacements and upgrades include the replacement, repair or improvement of an entire roof or a portion of the roof. Most roofs last 20-25 years, providing multiple opportunities over the life of the building to reevaluate roofing options as well to as assess a roof’s impact on the building’s energy and environmental performance. Opportunities include evaluating thermal performance, systems integration, rooftop HVAC upgrades, water management (storm runoff capture), indoor environmental quality, and the impact of the roofing material on the environment.^[1] For example, improving roof insulation can reduce heating and cooling needs, allowing for the downsizing of HVAC equipment, and further energy savings (see Insulation and Properly Sized HVAC Equipment). Selecting roofing materials with a high Solar Reflectance Index (SRI) reduces cooling loads, mitigates the urban heat island effect, and extends the life of the roof and rooftop mechanical equipment (see Cool Roofs). Incorporating skylights or solar tubes into a roof replacement or upgrade improves daylighting (see Daylighting). Green or vegetated roofs and rooftop cisterns provide stormwater management benefits (see Site and Stormwater Management). Replacing or upgrading a roof also provides the opportunity to consider on-site renewable energy systems and thermal energy storage. (See On-Site Renewable Energy Systems and Thermal Energy Storage). Non-toxic roofing materials with recycled content (e.g., cool metal roof) are available that are durable, low maintenance, and recyclable at the end of their useful life.^[2] Other advances in roofing technology include integrated data systems, such as drones that take infrared scans and provide alerts of water or moisture build-up on the roof or that provide pictures necessary for job estimates and simplify and improve roof installation and maintenance.^[3]

There are two main types of roofs: low-sloped and steep-sloped (the majority of commercial buildings have low-sloped roofs). The following lists roofing coverings for low-slope and steep-slope roofs.^[4]

Figure 2 – Roof types

How to Implement Roof Replacements and Upgrades

Automatically selecting a replacement or upgrade similar to the existing roof fails to recognize changes that affect roof and building performance such as the addition over time of new mechanical equipment, changing weather patterns, or unanticipated rooftop uses. When implementing a roof replacement or upgrades, consider roofing strategies that offer multiple benefits.

Many building codes and green building programs have a cool roof and urban heat island mitigation requirements that refer to ENERGY STAR and the Cool Roof Rating Council (CRRC) voluntary roof labeling programs (see Cool Roofs). Converting an existing roof into a cool roof involves either retrofitting the roof with heat-reflective coatings or materials, re-covering the roof with a new waterproofing surface or entirely replacing the roof with a new cool roof.^[7]

Examples

State of the Art in Enclosure Technologies and Integrated Systems for 50% Energy Savings in Existing Commercial Buildings.

The One-Factor-At-a-Time (OTA) Evaluation of Building Enclosure Measures Study demonstrated a 19.8% reduction in heating energy and a 17.1% reduction in total energy by installing R30 roof insulation cool roofing material with a high Solar Reflectance Index (SRI).^[8]

US Post Office and Courthouse, Camden, NJ

This retrofit roofing project, sponsored by the General Service Administration (GSA) Green Proving Ground (GPG) program, installed Vacuum Insulated Panels (VIPs) at the U.S. Post Office and Courthouse in Camden, New Jersey. VIPs consist of a solid interior layer of a high R-value material wrapped in an exterior layer of airtight foil with a vacuum drawn inside the airtight foil.^[9] The study used energy modeling and thermographic images and found that VIPs can offer a favorable payback in one-story buildings in regions with extreme climates and high utility costs.^[10] They can achieve an R-value of 50 without adding bulk, making them cost-effective on roofs.^[11]

Solar Panel System added to Distribution Facility in Edison, NJ.

With funding from the PSE&G Solar Loan Program, Avidan Management installed a 4.26-megawatt photovoltaic system in Edison, New Jersey, which produces 5 million kilowatt hours of power a year, about half of the power needs of the facility’s seventeen commercial tenants.^[12]

The Geraldine R. Dodge Foundation Green Roof, Morristown, NJ.

The Foundation’s 2,000 square foot vegetated roof, planted with native plant species, provides a home for many bird and butterfly species and absorbs 90% of rainfall.^[13]

Benefits

Roof improvement projects offer several potential benefits, including.

• Energy cost savings by reducing cooling loads.^[14]
• Lowered peak electricity demand which decreases the likelihood of power outages.^[15]
• Reduced roof temperatures which may reduce roof maintenance and replacement expenses by extending roof life.^[16]
• Increased indoor thermal comfort in summer, helping to prevent heat-related illness and deaths.^[17]
• Mitigated heat island effect in cities and suburbs.^[18]
• Reduced air pollution and smog formation.
• Water reduction savings for urban irrigation.^[19]
• Minimized heat loss in winter in cold climates when combined with appropriate insulation levels.^[20]

Costs

The cost of a roof replacement or upgrade varies depending on the type of roof improvement and scope of the project. Preventative maintenance and regular roof inspections help to save costs through early detection and avoided or reduced repair costs. Replacing the roof before it fails saves money by preventing extensive damage to the building interior. Prescheduling also allows time for evaluating roofing options, preparing specifications, and selecting a qualified and cost-competitive installer.

A roof’s life-cycle costs include upfront installation (materials and labor) and ongoing savings and maintenance costs (repair, recoating, and cleaning). The installed costs vary depending on the type and size of the roof, complexity of the roof system, and building location. For example, in cases where new roof surfaces need to be installed, adding a cool roof coating to a new roof cost about the same as adding a conventional dark roof with the cost premium ranging from $0.00 to $1.90/SF over conventional roofing products.^[21] Energy costs savings provide for a relatively short-term (1 year or less) payback.^[22]

For a list of price premiums for cool roof upgrades, see the Global Cool Cities Alliance’s Cool Roof and Pavements Toolkit. The City of New York Department of Design and Construction Cool & Green Roofing Manual also provides a cost analysis of green and cool roof upgrades. For up-to-date information on available incentives, please visit the New Jersey Clean Energy Program.

Resiliency

Well designed, correctly installed, and routinely maintained roofs contribute to resiliency by providing a durable roofing material and through energy efficiency.  For example, cool roofs enhance roofing durability by reducing thermal flux and increasing the roof’s resiliency to changing climate conditions, heat and UV aging.  Cool roofs also contribute to decreased air-conditioning loads, thereby extending the life of AC units. Regarding energy efficiency, adequately insulated roofs, can reduce heating and cooling loads, reducing stress on the grid, and help to regulate thermal comfort in the event of a power outage. In addition to stormwater management benefits, such as reduced flooding, vegetated roofs can offer the opportunity for local communities to grow food, reducing the dependency on supply chains and transportation networks often disrupted or compromised due to storms and other events.

^[1] Vivian Loftness et al. (2012) State of the Art in Enclosure Technologies and Integrated Systems for 50% Energy Savings in Existing Commercial Buildings. Consortium for Building Energy Innovation. http://cbei.psu.edu/wp-content/uploads/2016/07/State-of-the-Art-in-Enclosure-Technologies.pdf (accessed June 4, 2018).

^[2] Ibid.

^[3] BCC Research. Commercial Roofing in North America: Key Market Trends http://blog.bccresearch.com/commercial-roofing-webinar-recap (accessed May 31, 2018).

^[4] Whole Building Design Guide – Roofing Systems. https://www.wbdg.org/guides-specifications/building-envelope-design-guide/roofing-systems (accessed May 31, 2018).

^[5] Slope = rise/run. Low slope means that for every 12 horizontal inches, the roof’s rise is three vertical inches or less.

^[6] Slope = rise/run. Steep slope means that for every 12 horizontal inches, the roof’s rise is three vertical inches or greater.

^[7] US DOE. Cool Roofs. https://www.energy.gov/energysaver/energy-efficient-home-design/cool-roofs (accessed June 27, 2018).

^[8] Vivian Loftness et al. (2012) State of the Art in Enclosure Technologies and Integrated Systems for 50% Energy Savings in Existing Commercial Buildings. Consortium for Building Energy Innovation. Page 21. http://cbei.psu.edu/wp-content/uploads/2016/07/State-of-the-Art-in-Enclosure-Technologies.pdf (accessed June 4, 2018).

^[9] Dan Howell et al. “Vacuum Insulated Panels (VIPs) in a roofing application of US Post Office and Courthouse Camden, NJ.” March 2014. ORNL https://www.gsa.gov/cdnstatic/GPG_Vacuum_Insulated_Panels_03-2014.pdf (accessed May 29, 2018).

^[10] Ibid.

^[11] GSA. Green Proving Ground Program. “Vacuum Insulated Panels in Roofing Applications.” March 2016.  https://www.gsa.gov/governmentwide-initiatives/sustainability/emerging-technologies/published-findings/building-envelope/vacuum-insulated-panels (accessed May 29, 2018).

^[12] The Avidan Group -Solar. https://www.theavidangroup.com/solar2.html (accessed June 27, 2018).

^[13] WRT Planning and Design. A Sustainable Workplace: Geraldine R. Dodge Foundation Headquarters http://www.wrtdesign.com/work/geraldine-r-dodge-foundation-headquarters (accessed June 27, 2018).

^[14] US EPA. Using Cool Roofs to Reduce Heat Islands. https://www.epa.gov/heat-islands/using-cool-roofs-reduce-heat-islands (accessed March 16, 2018).

^[15] CRRC. “Resources for Code Officials and Policy Makers” http://coolroofs.org/documents/Policy.pdf (accessed March 16, 2018).

^[16] Bryan Urban and Kurt Roth, Ph.D. 2010. “Guidelines for Selection Cool Roofs.” V. 1.2. Prepared by the Fraunhofer Center for Sustainable Energy Systems for the U.S. Department of Energy Building Technologies Program and Oak Ridge National Laboratory. https://www.energy.gov/sites/prod/files/2013/10/f3/coolroofguide.pdf (accessed June 25, 2018).

^[17] US EPA. Using Cool Roofs to Reduce Heat Islands. https://www.epa.gov/heat-islands/using-cool-roofs-reduce-heat-islands (accessed March 16, 2018).

^[18] The “heat island effect” refers to developed areas that experience an increase in temperature that has the effect of increasing energy demands, air conditioning costs, greenhouse gas (GHG) emissions, and pollution while increasing the risk of heat-related illnesses.

^[19] Vahmani, Pouya. (2017) “Water Conservation Benefits of Urban Heat Mitigation.” Nature Communication 8, Article: 1072,  http://newscenter.lbl.gov/2017/10/20/cool-roofs-water-saving-benefits/ (accessed March 16. 2018).

^[20] Ramamurthy, P. et al. “The joint influence of albedo and insulation on roof performance: An observational study,” 2015, Energy and Buildings, Volume 93, pages 249-258. https://www.osti.gov/pages/biblio/1254734-joint-influence-albedo-insulation-roof-performance-observational-study (accessed March 18, 2018).

^[21] Global Cool Cities Alliance. 2012. “A Practical Guide to Cool Roofs and Cool Pavements: Primer.” Page 35. https://www.coolrooftoolkit.org/wp-content/pdfs/CoolRoofToolkit_Primer.pdf (accessed June 22, 2018).

^[22] Global Cool Cities Alliance. 2012. “A Practical Guide to Cool Roofs and Cool Pavements: Primer.” Page 35. https://www.coolrooftoolkit.org/wp-content/pdfs/CoolRoofToolkit_Primer.pdf (accessed June 22, 2018).