TECHNICAL SUPPORT DOCUMENT 

FOR

AMENDMENTS TO

COMAR 26.11.35 

ADHESIVES AND SEALANTS

FEBRUARY 12, 2009 

MARYLAND DEPARTMENT OF THE ENVIRONMENT

1800 Washington Boulevard 

Baltimore Maryland 21230 
 2 

This Page Left Intentionally Blank 
TABLE OF CONTENTS

Purpose and Background......................................................................................4 

Summary of Amendments.....................................................................................5 

Sources Affected.....................................................................................................5 

Technology Analysis ..............................................................................................5 

Impact on Ambient Air Quality............................................................................5 

Economic Impact ..................................................................................................6 

Appendix A.............................................................................................................7 

The Low-Slope Commercial Roofing Industry in the Northeast United States and the 

Ozone Transport Commission Model Rule for Adhesives and Sealants: 

A Study of Risks and Options for Effective Implementation 

 3 
Background 

Maryland's current requirements are based on the 2006 Ozone Transport Commission 

(OTC) model rule for adhesives and sealants. The OTC rule follows the reasonably 

available control technology (RACT) and best available retrofit control technology 

(BARCT) determination by the California Air Resources Board (CARB) developed in 

1998. Adhesives, sealants, adhesive primers, and sealant primers are used in 

manufacturing, packaging, construction, and installation of disparate materials such as 

metal, wood, rubber, plastic, ceramics, fiberglass and composites. An adhesive is any 

material used to bond two surfaces. A sealant is a material with adhesive properties that is 

used primarily to fill and seal durably, openings between two surfaces. 

The regulations affect a large number of sources and materials and provide significant 

reductions of VOCs. Due to the large scale impact of the regulations, the Department 

adopted the standards after an extensive analysis and outreach effort in 2007. The 

purpose was to give affected sources and manufacturers sufficient time to test new 

materials and make process changes to meet the new standards. The Adhesives and 

Sealants Council raised concerns to States about performance concerns for roofing 

adhesives when applied at lower temperatures. ERA and the EPDM Roofing Association 

requested more time for testing and for training users to work with lower VOC products 

during the colder, non ozone season months. 

The Department requested OTC to review these concerns in order to gather a multi-state 

perspective on this concern. The OTC did not recommend or make changes to the model 

rule after its review. The OTC, after technical review, left it up to the states to decide 

their course of action. During, and shortly following the OTC review process, four states 

and Washington D.C. decided to grant a non-ozone season exemption for the initial years 

of implementation. 

The Department continued to meet with manufacturers, installers and association 

representatives and requested additional information in support of their position. As a 

result of discussions and in order to provide more time for training, the Department 

agreed to provide a limited exemption for the non-ozone period during the initial phase of 

implementing the regulation. 

 

Purpose of Amendments 

These amendments exempt single-ply roof membrane installation and repair adhesives, 

single-ply roof membrane sealants and single-ply roof membrane adhesive primers from 

the standards for VOC content during the non-ozone season for the years 2009, 2010 and 

2011. In 2012 the standards for VOC content for these materials are applicable through 

out the year. These amendments affect manufacturers, suppliers, installers and users of 

single-ply roofing materials. 

 4 
Regulation Amendment Summary 

COMAR 26.11.35.01 Applicability and Exemptions is amended to limit the applicability 

of VOC standards for single-ply roof membrane installation and repair adhesives, singleply roof membrane sealants and single-ply roof membrane adhesive primers according to 

the following schedule: 

(1) For the year 2009, from May 15 through September 15; 

(2) For the years 2010 and 2011, from May 1 through September 

30: and 

 (3) On and after January 1, 2012. 

Affected Sources 

These proposed amendments affect manufacturers, suppliers, installers and users of 

single-ply roofing materials. 

Technology Analysis 

Bonding adhesives are used in single ply roofing application. The EPDM Roofing 

Association conducted a study on the feasibility of using bonding adhesives during the 

low temperature periods in the Northeast. The study states: “These bonding adhesives are 

composed of polymeric resins suspended in a variety of solvents. The majority of the 

solvents in single-ply bonding adhesives used today contain VOCs at rates higher than 

the 250 g/l standard established in the OTC Model Rule. Examples of these solvents 

include toluene, hexane and heptane. Because these solvents volatize at relatively low 

temperatures, they allow the effective application of single-ply roofing membranes within 

a relatively wide temperature range – from below freezing up to 100oF and beyond. 

Because of this wide useful temperature range, bonding adhesives using high VOC 

solvents are the preferred product choice for the commercial roofing contractor.” 

The study is included in Appendix A. New low VOC roofing adhesives are in 

development which should allow the effective application of single-ply roofing 

membranes under cold weather conditions. 

Impact on Ambient Air Quality 

The proposed amendments are designed to provide additional time for training and 

adaption to the use of new roofing adhesive materials. Roofing operations are performed 

at a lower rate during the non-ozone season. The release of VOCs during the non-ozone 

season has less of an impact upon the environment. The maximum benefit will continue 

to be provided in ozone season. 

 5 
Economic Impact 

These proposed regulatory changes are designed to provide relief for training and 

adaptation purposes and at the same time businesses can continue to use conventional 

materials during the non-ozone season. The amendment will lessen the economic impact 

on the affected sources in the initial stages of implementation. 

 6 
Appendix A 

The Low-Slope Commercial Roofing Industry in the Northeast United States and 

the Ozone Transport Commission Model Rule for Adhesives and Sealants: 

A Study of Risks and Options for Effective Implementation 

Prepared for the 

EPDM Roofing Association 

For submission to the 

Maryland Department of the Environment 

January 12, 2008 

Dr. James L. Hoff, DBA 

TEGNOS Research, Inc 

 3575 Seminole Dr. 609 Post Way 

Carmel, IN 46032 Tubac, AZ 85646 

Tel 317-679-1542 

www.tegnos.org 

 7 
The Low-Slope Commercial Roofing Industry in the Northeast United States and 

the Ozone Transport Commission Model Rule for Adhesives and Sealants: 

A Study of Risks and Options for Effective Implementation 

TABLE OF CONTENTS 

Page 

1. INTRODUCTION 3 

2. STUDY OBJECTIVES 5 

3. ANALYSIS 6 

 A. VOC Reduction in Roofing Systems: Technology Review 

 B. Climatic Factors: California v. Northeast U.S. 

 C. Product Usage Factors: California v. Northeast U.S. 

 D. VOC Emissions and Commercial Roofing Adhesives 

4. OVERALL RISK ASSESSMENT 14 

 A. Wind & Storm Risks

 B. Training & Performance Risks

 C. Seasonal Work Disruption and Uncertainty 

5. CONCLUSIONS 16 

6. RECOMMENDATIONS 18 

Copyright 2007 TEGNOS Research, Inc. 

 8 
1. INTRODUCTION 

As part of a regional effort to achieve Federally-mandated eight-hour ozone standards in 

the Northeast and Mid-Atlantic regions of the United States, the Ozone Transport 

Commission (OTC) developed a Model Rule for Adhesives and Sealants (OTC Model 

Rule). The provisions of this model rule limit emissions of volatile organic compounds 

(VOCs) from adhesives, sealants and primers. The OTC Model Rule achieves VOC 

reductions through two basic mechanisms: 1) sale and manufacture restrictions that limit 

the VOC content of specified adhesives, sealants and primers sold in the state, and 2) use 

restrictions that apply primarily to commercial/industrial applications. The OTC Model 

Rule was published by the OTC in 2007, with the stated goal of adoption and 

enforcement by individual states and local pollution control districts on or before January 

1, 2009. 

The OTC Model Rule is essentially identical to a similar model rule published by the 

California Air Resources Board (CARB) in 1998. In the years 1998-2001, the provisions 

of the CARB rule were adopted in regulatory form by various air pollution control 

districts in the state of California. Although the CARB model rule is described in the 

preamble of the OTC Model Rule to be a “reasonably available control technology,” the 

CARB rule was developed in region of the United States with climatic and economic 

factors that may differ significantly from the Northeast United States. In addition, these 

climatic and economic factors may have a significant influence on the effectiveness and 

overall impact of the OTC Model Rule on the environment and economy of the 

Northeast. 

The commercial low-slope roofing industry may provide an important example of how a 

model rule based on the climatic and market demands of California may adversely impact 

such a rule’s effectiveness in other areas of the country. Although it accounts for a 

relatively small portion of the larger economy within the Northeast United States, the 

commercial roofing industry provides a vital service to assure public safety and support 

commerce. By assuring the weather-tight integrity of buildings, properly installed and 

maintained commercial roofs protect the public from damage from storms and minimize 

long-term health problems associated with mold and other problems associated with 

leaky roofs. And by developing application technologies that can be utilized throughout 

the entire year in the Northeast United States, commercial roofers enable the larger 

commercial construction industry to operate on a year-round basis. 

Unfortunately, many of the adhesives developed by the roofing industry to meet the 

requirements of the California-based model rule were also developed to be effective 

primarily within the climatic and market conditions that occur in California; and some of 

these conditions differ significantly from conditions and practices in the Northeast. As an 

example, the adhesives used to secure modern roofing membranes to the roof surface 

(“bonding adhesives”) are generally effective and can only be applied when ambient air 

temperatures are at or above 40o

F and rising. While average minimum daily temperatures 

in California usually exceed the 40o

F minimum, this temperature is generally not 

 9 
available in the Northeast for many fall, winter and spring months. As a result, the 

conditions that currently allow the commercial roofing industry to provide safe and 

durable roofing systems for the Northeast in all seasons of the year may not be available 

with the promulgation of the OTC Model Rule in its current form. And although the 

commercial roofing industry contributes a relatively small portion of overall VOC 

emissions in the Northeast, the industry may bear a disproportionately negative impact 

under the OTC model rule. And in turn, this impact may significantly impede the roofing 

industry’s effectiveness in keeping buildings dry and allowing commercial construction 

activity to proceed on a year-round basis. 

Because of concerns regarding the overall impact of the OTC Model Rule, several 

organizations representing the commercial roofing industry have commissioned this 

study of the OTC Model Rule and its impact on commercial roofing in the Northeast. 

 10 
2. STUDY OBJECTIVES 

A. Identify the available technologies for reducing VOCs in commercial roofing systems 

and evaluate their suitability and effectiveness for use in the Northeast United States. 

B. Identify and quantify the differences between conditions in the state of California and 

Northeast states that may affect the overall utility and effectiveness of the OTC 

Model Rule as it applies to the commercial roofing industry. 

C. Identify and quantify and potentially significant adverse effects of the OTC Model 

Rule and commercial roofing in regard to commerce and public safety in Northeast 

states. 

D. Identify possible options that may maximize the effectiveness of the OTC Model 

Rule to reduce roofing-related VOC emissions in Northeast states while also 

maintaining the effectiveness of the roofing industry to perform its role of protecting 

the public and promoting commerce. 

 11 
3. ANALYSIS 

A. VOC Reduction in Roofing Systems: Technology Review 

VOCs in modern low-slope commercial roofing systems come primarily from three 

sources: 1) splicing adhesives used to bond the edges of roofing membranes to each 

other, 2) bonding adhesives used to bond the surface of roofing membranes to roof 

substrates and walls, and 3) sealants used to seal edges and terminations of roofing 

membranes to walls and roof projections. Of the three VOC product categories, two 

categories already employ low-VOC (less than 250 g/l) formulations throughout the 

United States and North America. In the case of splice adhesives, almost all single-ply 

roofing seams are currently mated using either 100% solids tapes (in the case of EPDM 

or rubber roofing materials), heat-welding (in the case of PVC / TPO or thermoplastic 

roofing materials), or hot asphalt (in the case of traditional asphalt and modified bitumen 

roofing materials). In the case of sealants, low-VOC, 100% solids products are both 

widely available and widely used throughout North America. Given the widespread use 

of low-VOC splicing and sealing technologies, the remaining category of bonding 

adhesive appears to be accountable for the overwhelming majority of VOCs produced in 

commercial roofing. This is due to both the current typical high-VOC content of the 

adhesives as well as the overall quantity of roof surface area requiring bonding as 

compared to the relatively small areas requiring panel seaming and edge sealing. 

The amount of VOCs generated by bonding adhesives may vary with the type of roofing 

system and the type of adhesive employed. In the case of asphalt roofing membranes, hot 

asphalt is the predominant adhesive, either applied with a mop to the membrane surface 

or derived from the membrane using a roofing torch. In the case of single-ply 

membranes, the predominant adhesives are contact adhesives that are sprayed or rollerapplied to both the membrane surface and the roofing substrate. These bonding adhesives 

are composed of polymeric resins suspended in a variety of solvents. The majority of the 

solvents in single-ply bonding adhesives used today contain VOCs at rates higher than 

the 250 g/l standard established in the OTC Model Rule. Examples of these solvents 

include toluene, hexane and heptane. Because these solvents volatize at relatively low 

temperatures, they allow the effective application of single-ply roofing membranes within 

a relatively wide temperature range – from below freezing up to 100o

F and beyond. 

Because of this wide useful temperature range, bonding adhesives using high VOC 

solvents are the preferred product choice for the commercial roofing contractor. 

Roof membrane bonding adhesives may also be formulated using low-VOC solvents, 

including acetone and water. Because these solvents do not volatize at low temperatures, 

their operating range is typically limited to temperatures consistently at or above 40oF. In 

addition, because they tend to volatize more slowly than high-VOC solvents, they are 

much more affected by ambient conditions, such as relative humidity and solar shading 

factors. As an example, a roofing membrane exposed partially to the sun and partially in 

the shade may “over dry” on the sunlit surface while the shaded surface remains too wet 

for installation. If the adhesive is allowed to dry too long, the adhesive bond may be 

weakened and the overall wind uplift resistance of the roofing system may be 

 12 
compromised. And if the adhesive is too wet when the membrane is installed, the roof 

will likely “blister,’ also compromising overall adhesion. As a consequence, the effective 

use of these adhesives – even under optimal temperature conditions – requires significant 

awareness, training and experience on the part of the roofing crew. 

Currently, high-VOC bonding adhesives dominate the commercial membrane roofing 

market. Shipping reports from EPDM Roofing Association (ERA) members indicate that 

over 95% of all single-ply bonding adhesives sold in the United States continue to 

employ high-VOC formulations. The only region of the country where low-VOC 

bonding adhesives currently dominate is the state of California, where low-VOC bonding 

adhesives have been mandated since the late 1990s. This would appear to indicate that 

customer preference will be difficult to change without a mandated regulation. However, 

this also suggests that little learning, preparation or adaptation to the special application 

requirements of low-VOC adhesives has occurred outside of mandated regions. 

The commercial roofing industry is currently working on several technologies that may 

reduce the VOC content of bonding adhesives, but these technologies have not yet been 

tested and demonstrated on a large scale, especially in the Northeast United States. 

Examples of these technologies include polyurethane foams, 100% solids, highmolecular-weight solvents, and thixotropic compounds. These technologies appear to 

offer value in addressing the needs of the roofing industry, especially in adapting to the 

extreme temperature range required for rooftop application. However, each of these 

technologies also comes with risks that have not yet been fully evaluated. Examples of 

these risks include 1) applicator familiarity and training, 2) long-term durability and 

service life, and 3) health concerns with some of the chemicals involved. 

In addition, all of these alternative technologies carry cost penalties between two and four 

times the cost of current high-VOC bonding adhesives. Although cost may not be an 

overriding consideration in view of the larger mission to reduce the environmental impact 

of VOCs, this cost differential must be considered in terms of its past effect in restricting 

research and new product development. Because roofing contractors and their building 

owner customers have been very reluctant to pay the current cost premiums required by 

alternative technologies, roofing manufacturers have been unable to conduct extensive 

testing and marketing of these products. Given sufficient development time, however, 

roofing manufacturers appear to be confident that a successful transition can be made 

from today’s high-VOC bonding adhesives to new low-VOC alternatives that can 

successfully address cold temperature applications. 

B. Climatic Factors: California v. Northeast U.S. 

A comparison of climate between California and Maryland indicates both similarities and 

contrasts. Figure 1 compares average monthly minimum and maximum temperature 

between cities in southern California (Los Angeles), northern California (Oakland), 

coastal Maryland (Baltimore), and inland Maryland (Hagerstown). 

 13 
Figure 1: Monthly Average High and Low Temperatures

(Source: The Weather Channel) 

44 47

57

68

77

86

91 88

81

70

59

49

29 31

39

48

58

68

73 71

64

52

42

33

10

20

30

40

50

60

70

80

90

100

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

68 70 70 73 75

80

84 85 84

79

73

67

48 50 52 54

58 61

65 66 65

60

53

48

10

20

30

40

50

60

70

80

90

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

57

61 63 66 69 72 73 73 75 72

64

58

Las Angeles, California

Ozone Season 

(Northeast US)

oF

45 48 49 51 53 56 57 58 58 55

49

45

10

20

30

40

50

60

70

80

90

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Oakland, California

Ozone Season 

(Northeast US)

oF

Ozone Season 

(Northeast US)

oF

Baltimore, Maryland

Hagerstown, MD

38

42

52

63

74

82 86 84

77

66

54

43

21 23

31

41

51

60 64 62

55

43

35

27

10

20

30

40

50

60

70

80

90

100

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Ozone Season 

(Northeast US)

oF

Operating Range of VOC-Compliant Single-Ply Roofing Bonding Adhesive under 

OTC Model Rule (<250 gm / l)

Average High Average Low

 14 
During the summer months of June through August, average high and low temperatures 

for Los Angeles and Baltimore are nearly identical, while Oakland and Hagerstown are 

slightly cooler. During the late spring and early fall, the temperature differential between 

the two California cities and the two Maryland cities begins to widen, as both the average 

high and low temperatures in the Maryland cities decline below the averages for the 

California cities. However, even during the early fall (September) and late spring (May), 

both high and low average temperatures for the Maryland cities fall within the operating 

range for currently available VOC-compliant membrane bonding adhesive technologies 

mentioned previously. It should be noted that the period from May through September, 

when average temperatures for the Maryland cities fall within the range of current VOCcompliant bonding adhesive technology, coincides with the “Ozone Season” for the 

Northeast United States as defined by the Ozone Transport Commission. 

The average temperature differentials between the two states increases further, however, 

during the late fall, winter, and early spring, with average temperatures for the Maryland 

cities declining and dropping below 40o

F. During the months from November through 

March, average temperatures for the Maryland cities are either well below or barely at the 

minimum operating temperatures required for current VOC-compliant roofing membrane 

adhesive technology. It should be noted, however that the period from October through 

April, when average temperatures in Washington drop below the range of current VOCcompliant bonding adhesive technology, falls outside the “Ozone Season” for the 

Northeast United States as defined by the Ozone Transport Commission. 

 15 
The challenges of the winter months in the Northeast are even more pronounced in terms 

of low temperatures, as shown in Figure 2 for the cities of Baltimore and Hagerstown: 

Figure 2: Monthly Record High and Low Temperatures 

(Source: The Weather Channel) 

Even during the most extreme events recorded, the high and low temperatures in the 

California cities still fall within the operating range for currently available VOCcompliant membrane bonding adhesive technologies throughout the entire year. In 

Maryland, however, the designated “ozone” months of May and September, which 

appear to be hospitable to low-VOC bonding adhesive in terms of average temperatures, 

may frequently experience low temperatures well below the 40o

F minimum for 

successful application of low-VOC bonding adhesives. 

78 81 86

95 96 99 104 103 99 93

84 78

-17

-9

2

18

30 37 42 40

29

18

8

-6

-20

0

20

40

60

80

100

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Hagerstown, MD

Ozone Season 

(Northeast US)

oF

Operating Range of VOC-Compliant Single-Ply Roofing Bonding Adhesive under 

OTC Model Rule (<250 gm / l)

Record High Record Low

79 84

97 98 100 105 107 105 102 97

87 85

-4 -7

11 15

32

46

54 52

40

30

12

-2

-20

0

20

40

60

80

100

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Baltimore, MD

Ozone Season 

(Northeast US)

oF

 16 
C. Product Usage Factors: California v. Northeast U.S. 

1) Historical Development of the U.S. Roofing Market. Prior to the development of 

modern single-ply roofing membranes in the 1970s and 1980s, almost all commercial 

roofs in the United States were constructed of asphalt materials, typically in redundant 

layers of roofing “felt” embedded in progressive applications of hot asphalt. However, 

the dominance of traditional asphalt roofing began to decline during the 1970s due to an 

unusual confluence of events. The Arab Oil Embargo forced refineries to derive more and 

more gallons of gasoline from every barrel of oil. As a consequence, the asphalt 

remaining at the “bottom of the barrel” contained fewer plastic elements and became 

more brittle. Increasing concerns about the health hazards of asbestos exerted a similar 

effect on roofing felts, as asbestos was replaced with weaker organic materials. The oil 

embargo also increased concerns about energy conservation, driving up the thickness of 

roof insulation. As roof insulation thickness increased, the overlying asphalt roof 

membrane became isolated thermally from the remainder of the building. As a result of 

this “thermal isolation,” the roofing membrane became subject to increasing temperature 

swings from solar heating during the day and freezing temperatures at night. Frequently, 

the embrittled asphalt and the weakened roofing felts frequently were unable to 

accommodate the thermal movement produced by these temperature swings. 

Starting in the 1970s single-ply roofing membranes made from rubber and plastic 

materials began to supplant traditional flat asphalt roofing. In place of redundant layers 

of felts, these materials provided a single, monolithic waterproofing layer. And instead of 

hot asphalt, single-ply membranes were frequently attached to the roofing substrate with 

contact adhesives. During the 1980s, sales of single-ply membranes began to accelerate, 

driven by the growth of one type of membrane in particular: EPDM, or rubber roofing. 

By the end of the1980s, annual sales of EPDM roofing membranes had grown to over 

one billion square feet, or approximately 1/3 of the entire low-slope commercial roofing 

market in the United States. 

2) Regional Market Differences. The strong growth of EPDM roofing was not uniform 

throughout the United States, however. In regions with infrequent freezing temperatures 

such as the West and Southwest, asphalt materials continued to dominate. However, in 

regions with frequent freezing temperatures such as the Midwest and Northeast, EPDM’s 

share of the commercial roofing market exceeds its 33% national average. The trend 

started in the 1980s continues to be demonstrated today in industry shipment statistics. 

Figure 3 compares the market share of EPDM, asphalt, and other single-ply (PVC & 

TPO) roofing membranes for the state of Maryland as compared to California in 2006. 

 17 
Figure 3: Annual Commercial Roofing Membrane Usage (Millions of Square Feet) 

(Source: SPRI 2006)

29,000,000

22,000,000

12,000,000

55,000,000

3,000,000

132,000,000

New Jersey

California

EPDM PVC/TPO Asphaltic

2%

29%

69%

35%

19%

46%

In the state of California in 2006, EPDM roofing accounted for only 2% of total lowslope roofing installations, as compared to 69% for asphalt membranes. However, in 

Maryland the ratio is significantly different, with EPDM membranes accounting for over 

1/3 of all roofing projects. Looking at the current mix of roofing materials used in 

Maryland and California, the data suggests that product preferences are influenced by 

climate. In Maryland, where temperature swings and freeze-thaw cycle are intense, the 

high flexibility of rubber roofing appears to be a significant consumer choice to avoid 

premature roof failure due to cracking or splitting. 

3) Regional Training / Experience Issues. Regardless of the factors behind the 

differences in product choice between California and Maryland, the fact that rubber 

roofing, which is a major product of choice in Maryland, has been rarely used in 

California may bring into question the OTC assumption that the experience of the 

California market provides a “reasonably available control technology” that can be 

immediately implemented in either Maryland or the Northeast. Although Maryland is 

much smaller in terms of area and population, every year over 22 million of EPDM roofs 

are installed as compared to only 3 million square feet in California. Because of the 

paucity of EPDM installations in California, it takes over 7 years of roofing experience 

 18 
with EPDM in California to equal the experience – and risk - with EPDM installations 

occurring in Maryland in a single year. 

Just as little practical experience relevant to the Northeast may have been obtained from 

California’s mandate for low-VOC bonding adhesives, little if any effort has yet been 

made to provide training for Maryland roofing workers in regard to effective application 

of low-VOC products. According to a survey of Maryland’s largest commercial roofing 

contractors, little or no formal training on low-VOC adhesives has yet been undertaken. 

In addition, shipment records of members of the EPDM Roofing Association indicate that 

fewer than 1000 gallons of low-VOC bonding adhesives are shipped annually to 

Maryland– indicating that Maryland contractors and their crews have little or no 

experience with low-VOC adhesives at this time. 

The lack of contractor training and experience with low-VOC bonding adhesives is 

particularly worrisome since the total number of roofing workers involved in roofing 

installation is relatively high. The consensus of roofing contractors contacted and 

interviewed for this study indicates that approximately 20,000 workers may be involved 

in roofing applications in Maryland annually. In addition, the contractors report high 

turnover rates that may increase this number, especially in terms of training needs. 

 19 
4. OVERALL RISK ASSESSMENT 

A. Wind & Storm Risks

The risk factors associated with compromised roof installation – especially in terms of 

adhesive securement – also appear to be higher in the Northeast than in California. As 

illustrated in the 50-year design wind speed map of the United States shown in Figure 4, 

large portions of California (especially the most populated areas) fall within the lowest 

wind design category of 70 miles per hour. In contrast, many areas of the Northeast fall 

within a much higher wind speed of 90 to 100 miles per hour, with even higher wind 

speed considerations along Atlantic coastal areas. 

Figure 4: Building Code Design Wind Speeds in the United States

(Source: Uniform Building Code)

In addition to higher design wind speeds, the consequences of wind-related roofing 

failures may be much more severe in the Northeast, where almost all extreme winds are 

associated with the cyclonic storms and hurricanes that may drop as much as 12 inches of 

water in a single day. As a result, what might be a minor wind incident during a hot 

“Santa-Anna” gust in California may be a major disaster causing extensive building 

damage compromising occupant safety during a significant wind and rain event in 

Maryland. 

 20 
B. Training & Performance Risks

Although roofing accounts for only about 6% of the total cost of a building, the National 

Roofing Legal Resource Center reports that roofing problems account for over 25% of all 

construction-related litigation. This high frequency of litigation has made roofing 

contractors especially conservative when it comes to the selection of roofing materials 

and methods. In fact, the market data showing that roofing contractors in Maryland 

prefer EPDM roofing in over 35% of all applications suggests that the contractors have 

established a definite preference for the product they believe will perform the best (and 

keep them out of the courts) given the specific climatic factors in Maryland and other 

parts of the Northeast. 

Because of differences in application skills and methods, any abrupt change made by the 

roofing contractor community could increase the risk of compromised roofing 

installations and roofing-related construction litigation. If roofing contractors in 

Maryland and the Northeast were to decide to return to a greater reliance on traditional 

asphalt systems in order to minimize their risk, they would have to re-train a workforce of 

approximately 20,000 roofing crew members to re-gain the traditional skills associated 

with applying and controlling hot asphalt. If the roofing contractors decide to stay with 

EPDM systems and immediately embrace low-VOC bonding adhesives, the same 20,000 

crew members will again need extensive training to assure the proper application of an 

adhesive system little-used and little-understood in the Northeast. 

 

C. Seasonal Work Disruption and Uncertainty 

With the exception of extreme snow and ice conditions, roofing work in Maryland and 

the Northeast continues throughout the year regardless of the season. If roofing 

contractors are forced to move too quickly to low-VOC bonding adhesives that are 

unsuitable for application at temperatures close to or below 40o

F, it is likely that roofing 

crews will be unable to work at all during the late fall, winter and early spring. In 

addition, even during the late spring and early fall, unsuitable daily temperature 

conditions may occur at a frequency that may make it unprofitable for roofing contractors 

to assemble and maintain crews available for work even on days when temperatures are 

favorable. This situation may not only increase unemployment among roofing crew 

members, but the disruption might spread to the entire commercial construction industry, 

as partially completed building sit empty and exposed to the weather until temperatures 

were suitable to install roofing materials. 

 21 
5. CONCLUSIONS 

The same data in this study that identify the risks associated with an abrupt switch to lowVOC bonding adhesives for roofing in the Northeast may also identify the best approach 

to avoid many of these financial and public safety risks. At the time of the year when 

ozone formation is of particular concern to the citizens of the Northeast, especially during 

the peak ozone months of July, August and September, temperature conditions are 

generally suitable for the use of current low-VOC bonding adhesive technology without 

overly compromising current roofing practice. And during the colder seasons of year 

when ozone formation is not a concern, traditional higher VOC adhesives could still be 

made available. Accordingly, a two-season approach may offer an effective optimization 

of the competing goals of VOC reduction and effective roofing practice. 

It is interesting to note that a similar two-season approach has already been proposed for 

the asphalt paving industry in the state of Connecticut. In a public hearing May 1, 2007, a 

draft amendment for Subsection (k) of Section 22a-174-20 of the Regulations of 

Connecticut Agencies was reviewed at a public hearing. This amendment, proposed for 

implementation January 1, 2009, calls for a restriction on high-VOC asphalt products 

during the period from May 1 through September 30 of each year, with no restriction on 

these products during the remainder of the year. The amendment also contains specific 

requirements regarding the record-keeping necessary to assure the effective 

implementation of such a two-season strategy. Specifically, the draft amendment for 

asphalt paving requires that all manufacturers, sellers, and contractors using asphalt 

paving materials to maintain and make available records of test, formulation, and usage 

data, and any other information necessary to determine compliance with the amendment 

for a period of five years. In addition, the proposed amendment includes a procedure to 

be followed by members of the paving industry in the event an exception to the 

amendment is required due to special circumstances, such as extreme cold conditions. 

Although the two-season proposal for asphalt paving may serve as an example for a 

similar approach for commercial roofing, there are several differences between the two 

industries that may require minor modification of the proposed asphalt paving rule to 

adopt it to the roofing industry. The first difference involves the relative maturity of lowVOC technology for paving materials as compared to roofing materials. In the same 

public hearing mentioned previously, the hearing officer stated that the technology of 

low-VOC asphalt was well-developed and that the industry was experienced with 

application differences: 

“Emulsified asphalts (Ed: Low-VOC technology) have been proven to perform at 

least as well as cutback asphalts (Ed: High-VOC technology) for all purposes 

during the ozone season. We recognize that during the 1980s there were problems 

with emulsified asphalts. Since that time there have been improvements in the 

technology and most applicators have become comfortable with the differences in 

application between cutback and emulsified asphalt. Additionally, asphalts that 

comply with this amendment have been in use and demonstrated to be 

 22 
successful.” (Connecticut DEP Hearing Report, Comment / Response No. 5, May 

1, 2007) 

Comparing the experience of the paving and roofing industries in regard to low-VOC 

technology, the asphalt paving industry may be much better prepared to adapt to the 

seasonal change to low-VOC products. Low-VOC asphalt products have been in use for 

over 20 years throughout the United States, while low-VOC bonding adhesives for 

roofing have only been in service – and on a very limited basis only in California – for 

less than 10 years. Comparing training and experience differences, it is important to 

reiterate(as previously mentioned in this report) that less than 1000 gallons of low-VOC 

bonding adhesive are shipped annually to Maryland and that Maryland roofing 

contractors have conducted little or no training with these adhesives. Accordingly, it 

would appear that roofing contractors are much less prepared than their paving 

counterparts to move quickly to low-VOC alternatives. 

 23 
6. RECOMMENDATIONS 

A. Use the Proposed Connecticut Asphalt Paving Rule as a Model for Commercial 

Roofing in the Northeast. 

The proposed Connecticut asphalt paving amendment, calling for the use of low-VOC 

products during the ozone season months of May through September, provides a 

reasonable basis for regulation of bonding adhesives within the commercial roofing 

industry. In order to align the requirements for the commercial roofing industry with the 

proposed rule for the paving industry, the OTC Model Rule for Adhesives and Sealants 

should be revised so that the 250 g/l maximum for “Single-Ply Roof Membrane 

Installation/Repair” is required only during the ozone season months of May through 

September. 

B. Provide a Transitional Period for Roofing Contractors to Adapt to Low-VOC 

Adhesives. 

Because low temperature extremes at the beginning and the end of the Northeast ozone 

season may frequently fall below the optimal operating range for low-VOC roof bonding 

adhesives, and because the commercial roofing industry in Maryland has yet to 

implement an extensive education and training program for its 20,000 workers, it would 

be reasonable to further provide a transitional period that would temporarily allow the use 

of high-VOC adhesives during the critical months at the beginning and end of the ozone 

season. This approach would allow commercial roofing contractors to first train their 

crews during the optimal months of the ozone season, and then extend this experience 

into the less optimal months. Specifically, it is recommended that the 250 g / l maximum 

for “Single-Ply Roof Membrane Installation/Repair” be phased according to the 

following schedule: 

Year: 250 g / l Required During:

 2009 July through August 

 2010 June through September 

 2011 May through September 

C. Develop a Reliable and Effective Industry-Sponsored Program to Assure 

Compliance with a Seasonal Approach 

The manufacturer members of the EPDM Roofing Association are responsible for the 

shipment of almost all rubber roofing membranes and over 90% of all rubber roofing 

bonding adhesives in the Northeast United States and Maryland. Given the broad 

involvement of the members of this trade association in the sale and delivery of rubber 

roofing adhesives, it would be reasonable to call upon them to act through their trade 

association to provide a reliable and effective program to assure that high-VOC adhesives 

 24 
are not available or used during the Northeast ozone season. Elements of this program 

should include: 

1. A moratorium on shipments of high-VOC bonding adhesives into Maryland 

during the months of May through September. 

2. A maximum limitation on shipments of high-VOC bonding adhesives into 

Maryland during the months of March and April to reduce the potential for 

stockpiling prior to the start of the ozone season. This limitation could be based 

on historical shipment records along with a reasonable percentage increase for 

market growth. In the event that a very large roofing project requires an unusual 

quantity of adhesive during this period, an exception program could be 

established to assure and verify that the adhesives are intended for specific 

identified projects scheduled to be completed prior to the beginning of the ozone 

season. 

3. A reporting program to verify that all customer stocks of high-VOC adhesives 

have been used prior to the beginning of the ozone season, or that any remaining 

stocks are safely stored until the end of the ozone season or returned to the 

manufacturer for disposal or re-shipment to areas of the country where high-VOC 

adhesives are permitted during the summer. 

4. A reporting program to provide the Maryland DEP with annual shipment 

information and VOC content of all rubber roofing adhesives shipped into 

Maryland. 

5. A requirement that all manufacturers and marketers of rubber roofing systems 

participate in the industry program in order to be eligible to ship high-VOC 

adhesives into Maryland, along with a requirement that the industry program be 

available to all manufacturers and marketers of rubber roofing systems regardless 

of membership in the industry trade association. 

 25 
 26 

TEGNOS Research, Inc. was founded in 2007 by Dr. James L. Hoff to serve the building 

industry by "Advancing Understanding of the Building Envelope"TM To accomplish this 

mission, TEGNOS provides professional services to trade and technical associations 

within the building industry, with an emphasis on research, education and advocacy. 

Additional information about TEGNOS can be found at http://www.tegnos.org. Dr. Hoff 

currently serves as the Research Director of the Center for Environmental Innovation in 

Roofing in Washington, DC, and is a board member of the RCI Foundation and the 

Performance Council for Constructed Roofing Systems.