AIA CES:Cool Roofing andCoating Systems

• Credit earned on completion of this program will be reported to CES Records for AIA members.

• Certificates of Completion for non-AIA members available on request.

Disclosure - 1

• This program is registered with the AIA/CES for continuing professional education.

• As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product.

• Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.

Disclosure - 2

Roof Coatings: Learning Objectives

After this training power point, you will be able to:

– Define a cool roof & understand the benefits of a cool roof.– Understand mitigating effects of Cool Roofing on Urban Heat Islands– Describe the options for “cool” roofing materials– Understand Energy Codes and Cool Roof Ratings systems– Investigate basic types of roof coatings and their compositions and

benefits – Evaluate the condition of a roof to determine if the roof is suitable for

coating.– Use rating guides to understand the best cool roofing option

Learning Objectives

Define a Cool Roof-Benefits of a Cool Roof

Cool Roof 101

What is a “cool” roof?

• A roof surface that stays relatively “cool” as compared to the ambient, or surrounding, temperature

Or…

• The roof surface temperature is usually only slightly higher than the air temperature

“Cool” Roof ?

• Architects are specifying cool roof products for all types of roofs, hip, square, flat, etc.

• Cool roofs come in a variety of materials and colors and can be applied to virtually any building or roof slope in any location.

• The extent of the benefits will be related to the building’s location, type and use, as well as to the specific selected roofing product.

• The broad range of locations in which cool roofs are proving to be a viable energy efficiency measure is growing.

• Cool roofs are roofing products that integrate materials with greater spectral reflectance than their traditional, non-cool counterparts, and thereby minimize the transfer of heat to the building below.

Cool Roof 101 - Introduction

• Codes, standards and programs typically reference the Solar Reflectance Index (SRI).

• SRI allows actual measured solar reflectance and thermal emitance values to be combined into a single value by determining how hot a surface would get relative to standard black and standard white surfaces.

• The standard black roofing material has a high emitance value (90 percent) but a low reflectance value (5 percent). This creates a hot roof surface because even though the emitance is high, there isn’t enough reflectance to help cool the roof. As such, the standard black roof is given an SRI value of 0.

• The standard white roofing material is highly reflective (80 percent) and has the same emitance as the standard black surface (90 percent). Its surface is much cooler and the standard white roof is assigned an SRI value of 100. Like solar reflectance and thermal emitance, a higher SRI value is synonymous with a cooler roof.

Solar Reflectance Index (SRI)

This diagram shows solar radiation on a roof surface. Image courtesy of Cool Roof Rating Council

Thermal Effects on a Roof

Building Operations alone are responsible for 43.5% of all energy consumed in the United States, while Building

Construction and Materials are responsible for an additional 5.5%.

.

77% of all Electricity generated in the US goes to operating Buildings

Buildings – Largest Emitter of Greenhouse Gases

Reduced Energy Costs

Studies show that building owners can save 20-70% in cooling costs, according to a Department of Energy study. And it is quickly becoming a requirement, with recent legislation like Title 24 in California and the Chicago Conservation Energy Code.

• Because cool roofs reduce air-conditioning use during the day’s hottest periods, the associated energy savings occur when the demand for electricity is at its peak.

• In addition, for building owners that pay for their energy based on the time of use, they save energy when it is at its most expensive – and save more money!

Peak Energy Savings & Grid Stability

• COOL ROOFS EQUATE TO BIG BENEFITS TO THE OWNER AND THE ENVIRONMENT

• Among the benefits to the building occupants and owner are:– Improved interior comfort– Reduced energy costs– Longer Mechanical Equipment unit life– Increased roof longevity– Decreased Life Cycle Cost

Cool Roofs – Big Benefits

Sacramento, CA; July 12, 2000 -- 89ºF, about noon, with local delta breeze

How “Cool” is a Cool Roof?

EPDM single-ply173 °F

BUR topped with capsheet 158 °F

BUR topped with aggregate 159 °F

Courtesy Dan Varvais, Applied Polymer Systems

Sacramento, CA; July 12, 2000 -- 89ºF, about noon, with local delta breeze

How “Cool” is a Cool Roof?

Cool coating over BUR 108 °F

Cool single-ply121 °F

Courtesy Dan Varvais, Applied Polymer Systems

• Cities can be 2° to 8°F warmer than surrounding areas due to dark materials, including roofs, which absorb the sun’s energy as heat during the day and release it at night.

• This phenomenon removes the opportunity for air to cool down at night resulting in higher temperatures being maintained longer.

• By immediately reflecting solar radiation back into the atmosphere and reemitting some portion of it as infrared light, cool roofs help create cooler air temperatures for the surrounding urban area during hot summer months.

• Through reduction of the urban heat island effect with the reduction of ambient air temperatures, cool roofs also improve air quality.

Urban Heat Island Mitigation

Row Houses – Absorb 95% of the Sun’s Heat + function as ovens

Cool Block Program in Philadelphia

Liquid Applied Coatings

Effective Solution

• It would be prudent to first check with the local or state building codes to determine if there are specific cool roofing requirements that must be satisfied. – Such is the case with the ASHRAE Standard 90.1, California’s Building

Energy Efficiency Standards, Title 24, NYCECC, as well as a number of other city building codes, including the Cities of Chicago, Houston, and Dallas.

– In addition, voluntary green building programs, such as The U.S. Green Building Council’s LEED® program

and the GreenGlobes™ environmental rating system, provide credit for cool roofs and several electric utility companies provide rebates.

Confirming with Local or State Codes and Requirements

• A cool roof should be chosen based on the slope of the roof, energy savings goals, the project location and climate, local code requirement, as well as aesthetic preferences.

• Designers who are seeking sustainable design credits may also want to consider the cradle-to-cradle aspects of their materials choices, including recycled content, end of life recyclability and use of toxic materials.

How to Chose a Cool Roof

ROOFING PRODUCT COOL VARIETY

Ballasted BUR, Single Ply White gravel

BUR w/ smooth asphalt coating White or reflective coating

BUR w/ aluminum coating White or reflective coating

Single ply EPDM, TPO, CSPE, PVC, PIB White coating or white membrane

Modified bitumen (SBS, APP) White, reflective coating, white granules

Metal roofing (painted and unpainted) White or cool color paint

Concrete tile White or cool tile or cool color paint

Fiber cement tile White or cool tile or cool color paint

Metal tile White or cool tile or cool color paint

Clay tile White or cool tile or cool color paint

Summary of Cool Roofing Options

• Rated product databases can assist the designer in selecting an appropriate cool roof product.

• These databases list pertinent product information that can be easily compared.

• These allow the designer to search roofing products by the initial and aged solar reflectance

and thermal emittance values as well as the slope application and type of roofing material.

Product Rating Resources

• While existing rating systems are complementary to one another, they do have slight differences in their requirements. ENERGY STAR, for example, aims to capture the most efficient products and set minimum requirements for both initial and aged solar reflectance.

• In order for a product to be listed by ENERGY STAR, it must meet their

minimum requirements as tested by CRRC (initial solar reflectance of 0.65 and three-year aged value of 0.50 for low-slope products and an initial reflectance of 0.25 and aged value of 0.15 for steep-sloped products).

Energy Star

CRRC’s work is limited to the top roofing layer , and the CRRC Product Label includes both reflectance and emitance data, for both initial and aged values. The CRRC uses three specific locations representing three key climate zones (hot/dry, hot/humid, and cold/temperate) to determine aged product performance over a 3 year period.

CRRC does:• Rate, or measure, the radiative properties of roof products• Publish performance data on the directoryCRRC does not:• Set a performance standard or define “cool”.

• Energy Star and state standards “Certify” or “approve” roofing products

What Is The Cool Roof Rating Council (CRRC)?

Understanding Cool Roof“Coatings”

• Dr. Steven Chu – mandated all Department of Energy Roofs – be coated with a “cool” white roof. He stated, the simple process of coating all roofs white globally with a “cool” roof, would have the same effect as removing all traffic off the streets for 12 years globally.

Government Mandates

• Roofs wear out because of:– Sunlight

• Heat• UV

– Freeze/Thaw– Roof Deck Movement– Oxygen– Precipitation

• It is more cost effective to maintain rather than to repair or replace (read: BIG $$)!

Coatings – Prolong Roof Life

• Applied over existing roofs without costly tear-offs or landfill waste.• Crews achieve much higher productivity versus installing BUR.• Your money goes into safe, "sustainable technology" materials, not excess labor.• Extends roof life, lowers cooling energy demand and lowers

life-cycle costs.• Each coating becomes more and more cost effective.

Liquid Applied Coatings Reduce Life-Cycle Costs

Ingredients of (Roof) Coatings

PigmentBinderAdditivesLiquid Solvent

Basic Components of Coatings

• Pigmentation (think: very tiny “rocks”)– provides whiteness, color, hiding, bulk

• Binder (think: glue)– binds pigment; provides adhesion

• Other Ingredients / Additives– improve coating and improve specific properties.

• Solids Content– proportion of pigment-and-binder to liquids that

evaporate when the coating dries.

Dimensions Defining Quality in a Coating

• Pigments: microscopic “rocks” • Provide Whiteness, Opacity, Color, Hiding, Bulk• Prime pigments:

– provide color, UV blocking– add in hiding, makes coating opaque

• Extenders: – provide bulk and economy

Pigments

Elastomeric Roof and Wall Coatings: The Theory

• Think “springs (polymer)” and “rocks (pigment)”– The higher the polymer level, the higher the elongation

(and lower tensile strength)– The higher the polymer level, the better the adhesion.

Think: “springs (polymer)” and “rocks (pigment)”

• Known for higher elongation/ lower tensile strength– Waterborne– Usually one component– Excellent UV durability– Excellent price/performance

balance

• Wide range of roof and wall coating applications

Acrylic Coatings

Polyurethane Coatings• Known for High Tensile Strength

and Exceptional Wear resistance• Outstanding Waterproofing ability

enables it to withstand long exposures to water

• Higher initial cost balanced by long term capability of the product

• Extremely effective in High Rise construction where roof square footage is small in comparison to overall building square footage.

• Roofing technologies include the traditional built-up roof (BUR), plus newer systems, such as various types of single ply and modified bitumen sheets and spray-applied polyurethane foam with a protective coating.

• Coatings are firmly established as an integral and required part of the urethane foam roofing system.

• The type of polyurethane used to make the foam is not durable if left uncoated and will begin to powder and degrade within weeks of application.

• Moreover, polyurethane foam is rather brittle and its skin can be cracked from impact with falling debris, heavy foot traffic, or severe hailstorms. Coatings protect the foam from these potential mishaps.

Coating Possibilities

Ease of Application

• Some liquid-applied coatings have also proven their utility over other substrates, and can be used to protect, restore, and prolong the life of aged existing built-up or other conventional roofing systems.

• Unlike re-roofing alternatives, they are extremely lightweight, adding virtually nothing to the load on the roof deck or supporting members.

• In fact, roofs may be re-coated several times without contributing significantly to the load.

• Once a roof is coated properly, it becomes a renewable system.

Extremely Light Weight

• By definition, they are liquid applied, fully adhered, elastomeric functional membranes formed in-situ on the existing roof.

• In the sense of being adherent to the substrate to which they are applied-in this case, the existing

roof-they are paint-like. • However, their elastomeric feature, which distinguishes them from paints, means they are also flexible.

Highly Flexible

Cool Roofs / Roof CoatingsIs a Roof Suitable for A Cool Coating

• For roofing jobs on existing buildings, the question faced by the roofing professional still remains the same: – Should an expensive new roof be installed or is there a roof replacement alternative which will prolong the life of the existing roof? – The answer may be a liquid applied membrane over the existing aged roof.

New Roof or Coating ?

Metal Failing Roof

Metal Roof Restored

Cap Sheet Failing Roof

Cap Sheet Restored Roof

PVC Failing Roof

PVC Restored Roof

TPO Roof with Logo Color Match

• As of March 2014, there are 125 field applied coating manufacturers

• There are 600 listed coatings• Which one is “right?”

CRRC Field Applied Coatings / Manufacturers

• The CRRC ( Cool Roof Rating Council) Ratings (Reflectance and Emitance only) Has been rated by the CRRC

• Energy Star Approved• Meets ASTM pedigree (D-6083 for acrylics)• Has many or extensive Product Line of Specialized Coatings for Different Roof Substrates• Manufacturer Reputation-Recognized Industry Awards• Track Record of Successful Projects!

How to Select a Quality Coating

CRRC Searchable Product Directory

CRRC Label Content

• Aged Data is “pending” until aged results are available• First aged results to be published around March 2007

• Liquid Applied Coatings Can:

– Reduce “Urban Heat Islands”– Reduce Ambient Air Temperature– Reduce Energy Costs– Improve Air Quality– Extend Roof Life– Reduce Roof Life Cycle Costs– Help Achieve USGBC LEED Credits

Summary