F.A.Q.s

Frequently Asked Questions

— submit a query in the comment form below or, well, I’ll just make up my own —

Q:   How many acres of green roofs are there in Bellingham?

A:   As of late 2012, the 11 green roofs that I currently know about here represent roughly 36,000 square feet, or about 3/4 of an acre. The current ownership mix is four public facilities, two commercial buildings, and five residences with green roofs.

Q:   Is less than an acre of green roof coverage pathetic for a town this size?

A:   Yes, but no — not really. Seattle, which likes to boast of being a “green” city, has a dismal track record on green roofs and some equally bleak numbers, with only 12-15 acres, for its coverage. The problem there, as the City of Seattle website laments, was that the roof designers did silly things: too thin with soil, too thoughtless with plant selection, and too eager to leave seagulls to do maintenance during the roof’s critical establishment phase. I think Bellingham should be proud of its start, especially considering it got this rolling with nearly zero incentives or active policy encouragement from the City of Bellingham.

Q:   OK, so Seattle is silly and Bellingham is pathetic. Which cities are super cool?

A:   Chicago has 7 million square feet of green roofs. Washington DC is nearing 2 million square feet. Portland has more than 1 million square feet of green roof coverage and is providing incentives to encourage at least 1 million more. Minneapolis, Philadelphia, San Francisco,  New York, and Vancouver BC seem poised to throw some equally impressive numbers in the coming years. For reference, 1,000,000 square feet is equal to roughly 23 acres. Some European cities seem to have given up on competitive tallies of this sort and instead talk percentages. Stuttgart, Germany, for example, claims to have %25 of its rooftops covered in green roofs. Cities achieve these huge numbers by providing incentives. If the project is eligible and the citizen is interested, then the local government will make their green roof installation an easy, potentially lucrative, choice.

Q:   I think I want incentives. What are they?

A:   Incentives seem to come in the form of tax reductions, cash dollars, or permit perks. The City of Bellingham, thanks to the recent adoption of AMM 303, will waive half of the stormwater impact fees and evaluate possible reductions in stormwater vaults or detention ponds which, for larger projects, are typically expensive and required. Chicago seems to have stopped giving cash grants, but Portland is still offering $5 per square foot of green roof installed. Portland and other cities also have permitting perks and financially tempting trades that can be dangled in front of developers. These carrots typically involve a bit of math: “If you (the builder) will put a green roof on your building which will cover %80 of the impermeable surface, then we (the City) will allow you to build % X taller, wider, or you can pay for that much less in proportional mitigation fees.”

Some cities, however, have become bored with incentives and have simply made green roofs mandatory.

Q:   Mandatory? That seems … excessive?

A:   Stuttgart, Toronto, and Copenhagen have all passed by-laws in the past year that make green roofs the first — rather than the last — option for builders of new roofs or re-roofing projects. Typically there is a size, or floor-area ratio, that triggers this requirement. None of these municipalities designed these policies on a whimsy. No hippie revolutions were involved. The City planners and policymakers simply crunched the numbers and said, “Yes, this makes sense for our city.” No jail time is on the books for those who thwart the laws, and exemptions for eccentric design or feeble roofs do exist. Still, if your building is physically able to handle a green roof, and yet you somehow find the idea repulsive, then punishing fines are headed your way. ¤

Q:   Are you sure no hippies were involved?

A:   For the most part, from glazing the rather plodding and serious action papers that Cities have published, it appears that only straight-laced bureaucrats, civil engineers, planners, and politicians are behind the large-scale push for green roofs. They decided to provide these incentives or to enact these laws for the sort of reasons that normally will bore decent hippies; lawsuits, balanced budgets, and public health.

Q:    I understand that the plants need to be the top layer for green roofs — I get that.  But lawsuits? Public health? And how, exactly, could a city expect to balance its budget by giving away money for green roofs?

A:   Portland got sued by the EPA for repeatedly failing to manage its stormwater overflows which, unfortunately, are still largely tied to the sewer system. Washington DC has similar legal issues because its rivers are becoming sewer canals whenever it rains. Lawsuits of this sort cost money directly, win or lose, and indirectly. (Federal money grants are often tied to compliance with Federal non-lawbreaking.) Another thing that will burst a city’s money pipe is installing a new municipal wastewater facility… and upgrading thousands of miles of pipes … and maintaining them … and doing it all over again whenever the city goes through its next growth spasm.

Green roofs seem to answer two problems related to this oscillating conundrum. On one hand they filter water, although not so significantly. On the two hand they slow water down, significantly. A sliding scale of effectiveness at capturing and retaining water seems to show that a green roof can soak up more than half the water which would otherwise be hustling on its way to blow the lids off sewer mains. (Portland’s survey of various monitored roofs averaged %56 reduced flows.) Thus a city saves money by not getting sued and by not having to build titanic infrastructure and facilities.

Public health, of course, is a concern when sewers overflow. Our species hates feces.

The real path from green roofs to public health, however, is a little less linear in its correlation than the scenarios mentioned above. Cleaner air, due to the natural pollution-scrubbing powers of green roof plants, is part of the equation. Asthma sufferers live in cities, after all, alongside some toddling babies, elderly folk, and literally millions of cars and trucks. The reduction of CO2 — even if no carbon tax credits are ever agreed upon in “climate negotiations” — would be a nice benefit, surely. But the public health benefit most often cited for green roofs seems to be their proven ability to reduce the urban heat island effect.

Green roofs reduce the temperature of buildings and cities. They save money when they reduce the temperature inside buildings, but they can save lives when they reduce the temperature outside. In Chicago, where 118 people died in one heatwave, green roofs are considered a real part of the solution to a real public health problem.

Q:  Bellingham is not Chicago. Bellingham isn’t even Portland and, realistically, it is barely Tukwilla on a good day. There’s no way this City of Subdued Excitement™ is going to get into the kind of trouble that the real cities tangle with. I rebuke thee!

A:   Fine. I suppose that $53.1 million for Bellingham’s new wastewater treatment facility is dainty sauce to you? You like having your taxes and water rates raised, right? And the fact that our drinking water supply, Lake Whatcom, is on the EPA’s “impaired waterbody” list — that is fine with you? Even I, a full-bloom green roof evangelist, would not proclaim the silly things can save the world and cleanse us of all sin. Still, it sure does appear that cities a lot bigger, smarter and wealthier than adorable ‘lil Bellingham, Washington, have decided to make significant commitments to green roofs as part of the solution to their ugliest problems.

Q:   Why do you hate Canada?

A:   I don’t, actually, hate Canada. I just thought the border patrol agents in Vancouver were a twee bit overzealous in detaining me for three hours for a crime no greater than wishing to attend a green roof conference in their country. Both days that I commuted up there were interrupted by their comically absurd and painfully dumb interrogations which, on the whole, managed to poison my rapport with an otherwise brilliant city.

They treated me like I was attempting to smuggle kitten heads to their pre-schoolers. I resent them for it.

Q:   Maybe they just don’t like hippies?

A:  Green roofs do provide significant insulation properties to a building. These properties, however, are not universally quantifiable. A 6″ deep green roof saturated with recent rainwater, for example, might insulate less than a 3″ deep dry roof. Green roof proponents slobber at the prospect of figuring out a magical formula to answer this question, and the studies are as thorough as they are convoluted.

What seems to make more sense, after finally accepting that every roof is different and will perform in this category strictly on nature’s terms, is to just analyze the side-by-side energy savings provided by green roofs. For heating and cooling costs a green roof installation seems to promise a %5-%15 reduction in a building’s energy demands.

If you really want to make your brain hyperventilate, however, then go ahead and read the literature associated with a green roof’s “R” rating. Pursuing this phantom number is like hunting unicorns with warm licorice, only 17.5 times less fun.

Q:   I’m sure all of that was fascinating … *yawn*… but, no thanks. I’m not about to spend my money to help the city clean its toilet water. Nor will I spend my money to help the dumb fish. I’m certainly not spending my hard-earned money on a green roof.

A:    While a lot of recent green roof installations have their genesis in seemingly altruistic motives, many others — especially the big ‘uns seen on corporate or industrial facilities — are increasingly the result of hard-nosed business decisions: Budgets, Money, The Bottom Line.

It should hardly surprise us that CEOs or property managers would suddenly  “go green” unless they really believed such a lark would feather their wallets or otherwise show return on investment. The mathematics used for this money modeling might look something like this: “I can pay for the installation of two conventional roofs which will each last 20 years” … “or I can pay for one green roof, which, although more expensive in initial costs, will last for 40 years or longer.” Green roofs in some markets might still be an exotic oddity. But where they are becoming common the price of their installation is going down to a point that a simple break even on material costs is possible: $10 per square foot for green roof materials vs. $5 per square foot for a conventional membrane is entirely feasible in Portland, for example.

The added savings accrued through stormwater tax reductions or other incentives (if available), the lifetime energy savings, and potentially being able to install smaller (cheaper) heating and cooling mechanics on a building can make a green roof investment even more obvious to corporate pencil-pushers. There are other cost benefits of green roofs that are tangible but not clearly quantifiable. A green roof can earn LEED credits for a building, for example, and those buildings certified by the LEED program are known to have an increased re-sale value.

In lieu of having actual 40-year-old roofs and their corresponding energy rates to assess, the range of savings can only be called theoretical at this point. Nonetheless, some wickedly smart people have studied the living tar out of this topic and they seem to believe that saving as much as %40 over the cost of conventional roofing is possible in some scenarios. While I did not scour every reference for “Life-cycle Cost” or “Net Present Value” — renal failure seemed imminent halfway through that quest — it did appear that some real-world buildings failed this sort of budget analysis due to the added cost of structural reinforcement needed to support the green roof’s weight. On the other hand, there are many, many, buildings that currently have green roofs today which made the freaky leap for little more reason than fear of financial foolishness.

Q:   Do you ever sleep?

A:   Sleep is for rookies.

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¤ (If I understand Toronto’s law correctly, any pecuniary funds that the City accrues from these theoretical fines must be channeled toward installing more green roof projects. Oh, Canada, how I ♥ Canada!)

1 Response to “F.A.Q.s”


  • I built a small studio (approximately 150 sq. ft.) about 5 years ago behind our house in the Sunnyland neighborhood. 2 years ago, we moved to the south side and brought the studio with us. The home mover who transported it nearly destroyed his lift while underestimating its weight. I used the old school method of 3/4″ stone as a drainage layer and about 4″-6″ of soil to hold a mixture of sedums, grasses, wild flowers, thyme, etc. It’s been a great adventure and every year the plant life just keeps getting more robust.
    Wish I’d heard about Bellingham Green Roofs earlier!
    Mark

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