Greener than Green

07/09/2008 | By Richard L. Fricklas

The focus in the roofing business this past year has been on energy conservation, sustainability, green roofs, and recycling. In terms of “new,” not much has been introduced in the way of roofing products and systems.

Perhaps this is due to the shrinking number of manufacturers in the roofing business through mergers and acquisitions, the achievement of stable and reliable roof systems, the attainment of commodity status for TPOs, or the fact that we have optimized roof performance, and gains will be harder to come by in the future.

Recently published data reveals that there are satisfactory alternatives to reflective roof coatings, such as ballasted roof systems, cool pigmented coatings for metal roofs, and the use of vented tile systems. This is good news for individuals who do not find white roofs particularly attractive, especially when dirt and mold build up, or when coatings start to crack and peel, requiring recoating. Energy-conserving pigments also offer alternatives to white, reducing the potential for glare complaints while offering more attractive earth tones.

The jolting increase in the cost of petroleum appears to be a permanent shift – one that will challenge us for years to come. Petroleum-based built-up roofs (BURs) and modified-bitumen (MB) systems may be especially hard hit. MB has survived in Europe, even though the cost of petroleum has been extremely high for decades since it used far less bitumen than the conventional BUR system.

In a 1992 issue of RSI magazine, a table was provided of the costs of energy that were current at the time.






















U.S. (Then)
U.S. (Now)



(For related information on the average cost of electricity in the United States, visit the Energy Information Administration website.)

Since it appears that the United States is just catching up to the rest of the world on petroleum prices, we should not expect a reversal to the good old days.
It is also evident from last month’s issue of Roofing News that we have maxed out on savings from increasing the minimum R-value of roof insulation. (ASHRAE 90.1 has recently raised the minimum R-value required for most commercial buildings to 20 from 15, with just a marginal improvement in energy savings.) We need to find and implement other ways to conserve energy.

Let’s consider some possibilities:





Increase durability

Delay disposal
(save cost of disposal and new roof)

Increased maintenance expenditures

Upgraded systems are available

Increase thermal mass

Reduce reliance on reflective coatings and aged R-value of foams

Increased weight

Concrete roof decks and ballast provide thermal lag

Increase slope

Better drainage;
conversion to sloped roof from flat may allow use of shingles;
attic improves ventilation

May cost more to make conversion

Sloped roofs require less maintenance

Increase drainage

Tapered insulation available

Best when reroofing

Able to redirect water to drains

Estimating the longevity of current roofing systems is very complex due to the number of variables. In 1996, members of Raleigh, NC-based RCI Inc.-The Institute of Roofing, Waterproofing, & Building Envelope Professionals were polled on their estimates of the effect of certain variables on membrane roof life. The following results were reported in the September 1997 issue of RCI’s Interface magazine.

Using a 3-ply BUR applied directly over Isoboard, respondents estimated an average roof life of 12.1 years.

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